WL#2936

"Server Variables for Plugins" Implement support for plugins to declare server variables. Demonstrate functionality by removing InnoDB specific code from sql/* New feature for HASH - HASH_UNIQUE flag New feature for DYNAMIC_ARRAY - initializer accepts preallocated ptr. Completed support for plugin reference counting. include/hash.h: New flag for HASH HASH_UNIQUE include/my_getopt.h: New data types for options: ENUM and SET. Use typelib to enumerate possible values. New flag variable: my_getopt_skip_unknown include/my_sys.h: change to DYNAMIC_ARRAY init functions to support pre-allocated buffers include/mysql.h: relocate inclusion of typelib due to longlong requirement include/mysql/plugin.h: wl2936 New declarations for plugin server variable support. New functions for use by plugins include/mysys_err.h: new my_getopt return value: EXIT_ARGUMENT_INVALID include/typelib.h: new typelib function: find_typeset(), returns an int which is a SET of the elements in the typelib mysql-test/r/im_utils.result: change to more specific command line settings --skip-innodb => --skip-plugin-innodb etc. mysql-test/r/log_tables.result: set default storage engine to MEMORY so that test will succeed even when some of the other named storage engines are not present mysql-test/r/ndb_dd_basic.result: change in error message mysql-test/r/partition_innodb.result: change in results mysql-test/r/ps_1general.result: bdb doesn't exist, use myisam for a non-transactional engine mysql-test/r/variables.result: information schema doesn't sort row results for server variables. mysql-test/t/log_tables.test: set default storage engine to MEMORY so that test will succeed even when some of the other named storage engines are not present mysql-test/t/ndb_dd_basic.test: ALTER LOGFILE GROUP no longer silently fail here mysql-test/t/partition_innodb.test: ALTER TABLE no longer silently fails for unknown storage engine mysql-test/t/ps_1general.test: remove unneccessary parts use myisam as it is an always present non-transactional engine mysql-test/t/variables.test: information schema doesn't sort row results for server variables. mysql-test/t/warnings_engine_disabled-master.opt: use the new style command line option mysys/array.c: change to DYNAMIC_ARRAY init functions to support pre-allocated buffers mysys/hash.c: New flag for HASH HASH_UNIQUE Implement HASH_UNIQUE functionality by performing a hash_search mysys/my_getopt.c: New data types for options: ENUM and SET. Use typelib to enumerate possible values. New flag variable: my_getopt_skip_unknown mysys/typelib.c: new typelib function: find_typeset(), returns an int which is a SET of the elements in the typelib sql/ha_ndbcluster.cc: use ha_statistic_increment() method instead of statistic_increment() function ha_ndbcluster variable has gone away. sql/ha_partition.cc: fix for reference counting sql/ha_partition.h: fix for reference counting sql/handler.cc: fixes for reference counting sql/handler.h: fixes for reference counting some new methods to aid storage engine writers sql/item_func.cc: find_sys_var() function now requires thd sql/item_sum.cc: fixes for ref counting sql/mysql_priv.h: remove unneccessary globals. new lock: LOCK_system_variables_hash sql/mysqld.cc: Remove InnoBase specific code. Support plugin command line processing. sql/set_var.cc: Remove InnoBase specific declarations Remove redundant declarations changes to permit new variables at run time changes for ref counting sql/set_var.h: changes to permit new variables at run time changes for ref counting sql/sql_base.cc: changes for ref counting sql/sql_cache.cc: mark code as needing work in the future sql/sql_class.cc: new functions to aid plugin authors initialize variables for dynamic plugin variables sql/sql_class.h: remove InnoBase specific declarations New declarations for plugin variables. sql/sql_connect.cc: initialization and cleanup of plugin variables sql/sql_delete.cc: change for ref counting sql/sql_insert.cc: change for ref counting sql/sql_lex.cc: changes for ref counting and plugin variables sql/sql_lex.h: add properties for plugin ref counting, add to distructor to clean up sql/sql_partition.cc: changes for ref counting sql/sql_plugin.cc: WL2936 Plugin Variables New methods and code to support server variables for plugins. New code to complete plugin reference counting Debug code adds further indirection so that malloc debugging can be used to aid finding plugin ref count leaks sql/sql_plugin.h: WL2936 Plugin Variables New methods and code to support server variables for plugins. New code to complete plugin reference counting Debug code adds further indirection so that malloc debugging can be used to aid finding plugin ref count leaks sql/sql_repl.cc: replication system variables moved here from set_var.cc sql/sql_repl.h: new function to initialise replication server variables sql/sql_select.cc: changes for ref counting sql/sql_show.cc: changes for ref counting sql/sql_table.cc: changes for ref counting sql/sql_tablespace.cc: use supplied functions instead of digging into data structures manually sql/sql_yacc.yy: changes for ref counting find_sys_var() now requires thd parameter changes on reporting errors to keep user-visible behaviour the same. sql/structs.h: changes for ref counting sql/table.cc: changes for ref counting sql/table.h: changes for ref counting storage/federated/ha_federated.cc: use ha_statistic_increment() method instead of statistic_increment() function storage/heap/ha_heap.cc: use ha_statistic_increment() method instead of statistic_increment() function storage/innobase/handler/ha_innodb.cc: use ha_statistic_increment() method instead of statistic_increment() function WL2936 Move InnoBase specific code out of mysqld.cc and into here Declare all required server variables for InnoBase storage/innobase/include/trx0trx.h: store a bit more state so that InnoBase does not have to dig into mysqld internal data structures. storage/myisam/ha_myisam.cc: use ha_statistic_increment() method instead of statistic_increment() function storage/myisammrg/ha_myisammrg.cc: use ha_statistic_increment() method instead of statistic_increment() function
author: unknown <antony@ppcg5.local> 2007-03-02 08:43:45 -0800
committer: unknown <antony@ppcg5.local> 2007-03-02 08:43:45 -0800
commit: 1fc7f2117bddfcf91e1220f22714beb86d26c544 (patch)
tree: 23fe49e9ab83f6badb4e173587f9e194490a3859 /sql
parent: 1eb71c68cb1b2f335a8e6b393cdb3e724ea65a0a (diff)
download: mariadb-git-1fc7f2117bddfcf91e1220f22714beb86d26c544.tar.gz
33 files changed, 3641 insertions, 1830 deletions
diff --git a/sql/ha_ndbcluster.cc b/sql/ha_ndbcluster.cc
index 393856e62ba..4f4f32c1fa5 100644
--- a/sql/ha_ndbcluster.cc
+++ b/sql/ha_ndbcluster.cc
@@ -2629,7 +2629,7 @@ int ha_ndbcluster::write_row(byte *record)
       DBUG_RETURN(peek_res);
   }
 
-  statistic_increment(thd->status_var.ha_write_count, &LOCK_status);
+  ha_statistic_increment(&SSV::ha_write_count);
   if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_INSERT)
     table->timestamp_field->set_time();
 
@@ -2849,7 +2849,7 @@ int ha_ndbcluster::update_row(const byte *old_data, byte *new_data)
       DBUG_RETURN(peek_res);
   }
 
-  statistic_increment(thd->status_var.ha_update_count, &LOCK_status);
+  ha_statistic_increment(&SSV::ha_update_count);
   if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_UPDATE)
   {
     table->timestamp_field->set_time();
@@ -3016,7 +3016,7 @@ int ha_ndbcluster::delete_row(const byte *record)
   DBUG_ENTER("delete_row");
   m_write_op= TRUE;
 
-  statistic_increment(thd->status_var.ha_delete_count,&LOCK_status);
+  ha_statistic_increment(&SSV::ha_delete_count);
   m_rows_changed++;
 
   if (m_use_partition_function &&
@@ -3372,7 +3372,7 @@ int ha_ndbcluster::index_read_idx(byte *buf, uint index_no,
                               const byte *key, uint key_len, 
                               enum ha_rkey_function find_flag)
 {
-  statistic_increment(current_thd->status_var.ha_read_key_count, &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_key_count);
   DBUG_ENTER("ha_ndbcluster::index_read_idx");
   DBUG_PRINT("enter", ("index_no: %u, key_len: %u", index_no, key_len));  
   close_scan();
@@ -3384,8 +3384,7 @@ int ha_ndbcluster::index_read_idx(byte *buf, uint index_no,
 int ha_ndbcluster::index_next(byte *buf)
 {
   DBUG_ENTER("ha_ndbcluster::index_next");
-  statistic_increment(current_thd->status_var.ha_read_next_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_next_count);
   DBUG_RETURN(next_result(buf));
 }
 
@@ -3393,8 +3392,7 @@ int ha_ndbcluster::index_next(byte *buf)
 int ha_ndbcluster::index_prev(byte *buf)
 {
   DBUG_ENTER("ha_ndbcluster::index_prev");
-  statistic_increment(current_thd->status_var.ha_read_prev_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_prev_count);
   DBUG_RETURN(next_result(buf));
 }
 
@@ -3402,8 +3400,7 @@ int ha_ndbcluster::index_prev(byte *buf)
 int ha_ndbcluster::index_first(byte *buf)
 {
   DBUG_ENTER("ha_ndbcluster::index_first");
-  statistic_increment(current_thd->status_var.ha_read_first_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_first_count);
   // Start the ordered index scan and fetch the first row
 
   // Only HA_READ_ORDER indexes get called by index_first
@@ -3414,7 +3411,7 @@ int ha_ndbcluster::index_first(byte *buf)
 int ha_ndbcluster::index_last(byte *buf)
 {
   DBUG_ENTER("ha_ndbcluster::index_last");
-  statistic_increment(current_thd->status_var.ha_read_last_count,&LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_last_count);
   DBUG_RETURN(ordered_index_scan(0, 0, TRUE, TRUE, buf, NULL));
 }
 
@@ -3600,8 +3597,7 @@ int ha_ndbcluster::rnd_end()
 int ha_ndbcluster::rnd_next(byte *buf)
 {
   DBUG_ENTER("rnd_next");
-  statistic_increment(current_thd->status_var.ha_read_rnd_next_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_rnd_next_count);
 
   if (!m_active_cursor)
     DBUG_RETURN(full_table_scan(buf));
@@ -3619,8 +3615,7 @@ int ha_ndbcluster::rnd_next(byte *buf)
 int ha_ndbcluster::rnd_pos(byte *buf, byte *pos)
 {
   DBUG_ENTER("rnd_pos");
-  statistic_increment(current_thd->status_var.ha_read_rnd_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_rnd_count);
   // The primary key for the record is stored in pos
   // Perform a pk_read using primary key "index"
   {
@@ -6743,7 +6738,7 @@ static int ndbcluster_init(void *p)
 
   {
     handlerton *h= ndbcluster_hton;
-    h->state=            have_ndbcluster;
+    h->state=            SHOW_OPTION_YES;
     h->db_type=          DB_TYPE_NDBCLUSTER;
     h->close_connection= ndbcluster_close_connection;
     h->commit=           ndbcluster_commit;
@@ -6765,9 +6760,6 @@ static int ndbcluster_init(void *p)
     h->table_exists_in_engine= ndbcluster_table_exists_in_engine;
   }
 
-  if (have_ndbcluster != SHOW_OPTION_YES)
-    DBUG_RETURN(0); // nothing else to do
-
   // Initialize ndb interface
   ndb_init_internal();
 
@@ -6883,7 +6875,6 @@ ndbcluster_init_error:
   if (g_ndb_cluster_connection)
     delete g_ndb_cluster_connection;
   g_ndb_cluster_connection= NULL;
-  have_ndbcluster= SHOW_OPTION_DISABLED;	// If we couldn't use handler
   ndbcluster_hton->state= SHOW_OPTION_DISABLED;               // If we couldn't use handler
 
   DBUG_RETURN(TRUE);
@@ -10220,10 +10211,6 @@ ndbcluster_show_status(handlerton *hton, THD* thd, stat_print_fn *stat_print,
   uint buflen;
   DBUG_ENTER("ndbcluster_show_status");
   
-  if (have_ndbcluster != SHOW_OPTION_YES) 
-  {
-    DBUG_RETURN(FALSE);
-  }
   if (stat_type != HA_ENGINE_STATUS)
   {
     DBUG_RETURN(FALSE);
diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc
index 87d24207dcd..d8fd3b5f934 100644
--- a/sql/ha_partition.cc
+++ b/sql/ha_partition.cc
@@ -1987,6 +1987,8 @@ bool ha_partition::create_handler_file(const char *name)
 
 void ha_partition::clear_handler_file()
 {
+  if (m_engine_array)
+    plugin_unlock_list(NULL, m_engine_array, m_tot_parts);
   my_free((char*) m_file_buffer, MYF(MY_ALLOW_ZERO_PTR));
   my_free((char*) m_engine_array, MYF(MY_ALLOW_ZERO_PTR));
   m_file_buffer= NULL;
@@ -2009,6 +2011,7 @@ bool ha_partition::create_handlers(MEM_ROOT *mem_root)
 {
   uint i;
   uint alloc_len= (m_tot_parts + 1) * sizeof(handler*);
+  handlerton *hton0;
   DBUG_ENTER("create_handlers");
 
   if (!(m_file= (handler **) alloc_root(mem_root, alloc_len)))
@@ -2017,19 +2020,21 @@ bool ha_partition::create_handlers(MEM_ROOT *mem_root)
   bzero((char*) m_file, alloc_len);
   for (i= 0; i < m_tot_parts; i++)
   {
+    handlerton *hton= plugin_data(m_engine_array[i], handlerton*);
     if (!(m_file[i]= get_new_handler(table_share, mem_root,
-                                     m_engine_array[i])))
+                                     hton)))
       DBUG_RETURN(TRUE);
-    DBUG_PRINT("info", ("engine_type: %u", m_engine_array[i]->db_type));
+    DBUG_PRINT("info", ("engine_type: %u", hton->db_type));
   }
   /* For the moment we only support partition over the same table engine */
-  if (m_engine_array[0] == myisam_hton)
+  hton0= plugin_data(m_engine_array[0], handlerton*);
+  if (hton0 == myisam_hton)
   {
     DBUG_PRINT("info", ("MyISAM"));
     m_myisam= TRUE;
   }
   /* INNODB may not be compiled in... */
-  else if (ha_legacy_type(m_engine_array[0]) == DB_TYPE_INNODB)
+  else if (ha_legacy_type(hton0) == DB_TYPE_INNODB)
   {
     DBUG_PRINT("info", ("InnoDB"));
     m_innodb= TRUE;
@@ -2160,8 +2165,7 @@ bool ha_partition::get_from_handler_file(const char *name, MEM_ROOT *mem_root)
   m_tot_parts= uint4korr((file_buffer) + 8);
   DBUG_PRINT("info", ("No of parts = %u", m_tot_parts));
   tot_partition_words= (m_tot_parts + 3) / 4;
-  if (!(engine_array= (handlerton **) my_malloc(m_tot_parts * sizeof(handlerton*),MYF(0))))
-    goto err2;
+  engine_array= (handlerton **) my_alloca(m_tot_parts * sizeof(handlerton*));
   for (i= 0; i < m_tot_parts; i++)
     engine_array[i]= ha_resolve_by_legacy_type(current_thd,
                                                (enum legacy_db_type)
@@ -2174,7 +2178,14 @@ bool ha_partition::get_from_handler_file(const char *name, MEM_ROOT *mem_root)
   VOID(my_close(file, MYF(0)));
   m_file_buffer= file_buffer;          // Will be freed in clear_handler_file()
   m_name_buffer_ptr= name_buffer_ptr;
-  m_engine_array= engine_array;
+  
+  if (!(m_engine_array= (plugin_ref*)
+                my_malloc(m_tot_parts * sizeof(plugin_ref), MYF(MY_WME))))
+    goto err2;
+
+  for (i= 0; i < m_tot_parts; i++)
+    m_engine_array[i]= ha_lock_engine(NULL, engine_array[i]);
+    
   if (!m_file && create_handlers(mem_root))
   {
     clear_handler_file();
diff --git a/sql/ha_partition.h b/sql/ha_partition.h
index 4fdf325fa06..a2904562930 100644
--- a/sql/ha_partition.h
+++ b/sql/ha_partition.h
@@ -27,6 +27,7 @@ enum partition_keywords
   The partition implements the minimum of what you will probably need.
 */
 
+#ifdef NOT_USED
 typedef struct st_partition_share
 {
   char *table_name;
@@ -34,6 +35,7 @@ typedef struct st_partition_share
   pthread_mutex_t mutex;
   THR_LOCK lock;
 } PARTITION_SHARE;
+#endif
 
 
 #define PARTITION_BYTES_IN_POS 2
@@ -54,7 +56,7 @@ private:
   uint m_open_test_lock;                // Open test_if_locked
   char *m_file_buffer;                  // Buffer with names
   char *m_name_buffer_ptr;		// Pointer to first partition name
-  handlerton **m_engine_array;          // Array of types of the handlers
+  plugin_ref *m_engine_array;           // Array of types of the handlers
   handler **m_file;                     // Array of references to handler inst.
   uint m_file_tot_parts;                // Debug
   handler **m_new_file;                 // Array of references to new handlers
@@ -130,7 +132,9 @@ private:
     Variables for lock structures.
   */
   THR_LOCK_DATA lock;                   /* MySQL lock */
+#ifdef NOT_USED
   PARTITION_SHARE *share;               /* Shared lock info */
+#endif
 
 public:
   virtual void set_part_info(partition_info *part_info)
diff --git a/sql/handler.cc b/sql/handler.cc
index 2244aaa5311..bb7c39be262 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -77,6 +77,15 @@ static TYPELIB known_extensions= {0,"known_exts", NULL, NULL};
 uint known_extensions_id= 0;
 
 
+
+static plugin_ref ha_default_plugin(THD *thd)
+{
+  if (thd->variables.table_plugin)
+    return thd->variables.table_plugin;
+  return my_plugin_lock(thd, &global_system_variables.table_plugin);
+}
+
+
 /** @brief
   Return the default storage engine handlerton for thread
 
@@ -89,10 +98,11 @@ uint known_extensions_id= 0;
 */
 handlerton *ha_default_handlerton(THD *thd)
 {
-  return (thd->variables.table_type != NULL) ?
-          thd->variables.table_type :
-          (global_system_variables.table_type != NULL ?
-           global_system_variables.table_type : myisam_hton);
+  plugin_ref plugin= ha_default_plugin(thd);
+  DBUG_ASSERT(plugin);
+  handlerton *hton= plugin_data(plugin, handlerton*);
+  DBUG_ASSERT(hton);
+  return hton;
 }
 
 
@@ -105,26 +115,30 @@ handlerton *ha_default_handlerton(THD *thd)
     name        name of storage engine
   
   RETURN
-    pointer to handlerton
+    pointer to storage engine plugin handle
 */
-handlerton *ha_resolve_by_name(THD *thd, const LEX_STRING *name)
+plugin_ref ha_resolve_by_name(THD *thd, const LEX_STRING *name)
 {
   const LEX_STRING *table_alias;
-  st_plugin_int *plugin;
+  plugin_ref plugin;
 
 redo:
   /* my_strnncoll is a macro and gcc doesn't do early expansion of macro */
   if (thd && !my_charset_latin1.coll->strnncoll(&my_charset_latin1,
                            (const uchar *)name->str, name->length,
                            (const uchar *)STRING_WITH_LEN("DEFAULT"), 0))
-    return ha_default_handlerton(thd);
+    return ha_default_plugin(thd);
 
-  if ((plugin= plugin_lock(name, MYSQL_STORAGE_ENGINE_PLUGIN)))
+  if ((plugin= my_plugin_lock_by_name(thd, name, MYSQL_STORAGE_ENGINE_PLUGIN)))
   {
-    handlerton *hton= (handlerton *)plugin->data;
+    handlerton *hton= plugin_data(plugin, handlerton *);
     if (!(hton->flags & HTON_NOT_USER_SELECTABLE))
-      return hton;
-    plugin_unlock(plugin);
+      return plugin;
+      
+    /*
+      unlocking plugin immediately after locking is relatively low cost.
+    */
+    plugin_unlock(thd, plugin);
   }
 
   /*
@@ -145,19 +159,19 @@ redo:
 }
 
 
-const char *ha_get_storage_engine(enum legacy_db_type db_type)
+plugin_ref ha_lock_engine(THD *thd, handlerton *hton)
 {
-  switch (db_type) {
-  case DB_TYPE_DEFAULT:
-    return "DEFAULT";
-  default:
-    if (db_type > DB_TYPE_UNKNOWN && db_type < DB_TYPE_DEFAULT &&
-        installed_htons[db_type])
-      return hton2plugin[installed_htons[db_type]->slot]->name.str;
-    /* fall through */
-  case DB_TYPE_UNKNOWN:
-    return "UNKNOWN";
+  if (hton)
+  {
+    st_plugin_int **plugin= hton2plugin + hton->slot;
+    
+#ifdef DBUG_OFF;
+    return my_plugin_lock(thd, plugin);
+#else
+    return my_plugin_lock(thd, &plugin);
+#endif
   }
+  return NULL;
 }
 
 
@@ -172,14 +186,16 @@ static handler *create_default(TABLE_SHARE *table, MEM_ROOT *mem_root)
 
 handlerton *ha_resolve_by_legacy_type(THD *thd, enum legacy_db_type db_type)
 {
+  plugin_ref plugin;
   switch (db_type) {
   case DB_TYPE_DEFAULT:
     return ha_default_handlerton(thd);
-  case DB_TYPE_UNKNOWN:
-    return NULL;
   default:
-    if (db_type > DB_TYPE_UNKNOWN && db_type < DB_TYPE_DEFAULT)
-      return installed_htons[db_type];
+    if (db_type > DB_TYPE_UNKNOWN && db_type < DB_TYPE_DEFAULT &&
+        (plugin= ha_lock_engine(thd, installed_htons[db_type])))
+      return plugin_data(plugin, handlerton*);
+    /* fall through */
+  case DB_TYPE_UNKNOWN:
     return NULL;
   }
 }
@@ -199,7 +215,7 @@ handlerton *ha_checktype(THD *thd, enum legacy_db_type database_type,
   {
     if (report_error)
     {
-      const char *engine_name= ha_get_storage_engine(database_type);
+      const char *engine_name= ha_resolve_storage_engine_name(hton);
       my_error(ER_FEATURE_DISABLED,MYF(0),engine_name,engine_name);
     }
     return NULL;
@@ -238,8 +254,7 @@ handler *get_new_handler(TABLE_SHARE *share, MEM_ROOT *alloc,
     Here the call to current_thd() is ok as we call this function a lot of
     times but we enter this branch very seldom.
   */
-  DBUG_RETURN(get_new_handler(share, alloc,
-                              current_thd->variables.table_type));
+  DBUG_RETURN(get_new_handler(share, alloc, ha_default_handlerton(current_thd)));
 }
 
 
@@ -522,10 +537,10 @@ int ha_end()
   DBUG_RETURN(error);
 }
 
-static my_bool dropdb_handlerton(THD *unused1, st_plugin_int *plugin,
+static my_bool dropdb_handlerton(THD *unused1, plugin_ref plugin,
                                  void *path)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->drop_database)
     hton->drop_database(hton, (char *)path);
   return FALSE;
@@ -538,10 +553,10 @@ void ha_drop_database(char* path)
 }
 
 
-static my_bool closecon_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool closecon_handlerton(THD *thd, plugin_ref plugin,
                                    void *unused)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   /*
     there's no need to rollback here as all transactions must
     be rolled back already
@@ -638,7 +653,7 @@ int ha_prepare(THD *thd)
       {
         push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                             ER_ILLEGAL_HA, ER(ER_ILLEGAL_HA),
-                            hton2plugin[(*ht)->slot]->name.str);
+                            ha_resolve_storage_engine_name(*ht));
       }
     }
   }
@@ -886,10 +901,10 @@ struct xahton_st {
   int result;
 };
 
-static my_bool xacommit_handlerton(THD *unused1, st_plugin_int *plugin,
+static my_bool xacommit_handlerton(THD *unused1, plugin_ref plugin,
                                    void *arg)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->recover)
   {
     hton->commit_by_xid(hton, ((struct xahton_st *)arg)->xid);
@@ -898,10 +913,10 @@ static my_bool xacommit_handlerton(THD *unused1, st_plugin_int *plugin,
   return FALSE;
 }
 
-static my_bool xarollback_handlerton(THD *unused1, st_plugin_int *plugin,
+static my_bool xarollback_handlerton(THD *unused1, plugin_ref plugin,
                                      void *arg)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->recover)
   {
     hton->rollback_by_xid(hton, ((struct xahton_st *)arg)->xid);
@@ -1004,10 +1019,10 @@ struct xarecover_st
   bool dry_run;
 };
 
-static my_bool xarecover_handlerton(THD *unused, st_plugin_int *plugin,
+static my_bool xarecover_handlerton(THD *unused, plugin_ref plugin,
                                     void *arg)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   struct xarecover_st *info= (struct xarecover_st *) arg;
   int got;
 
@@ -1016,7 +1031,7 @@ static my_bool xarecover_handlerton(THD *unused, st_plugin_int *plugin,
     while ((got= hton->recover(hton, info->list, info->len)) > 0 )
     {
       sql_print_information("Found %d prepared transaction(s) in %s",
-                            got, hton2plugin[hton->slot]->name.str);
+                            got, ha_resolve_storage_engine_name(hton));
       for (int i=0; i < got; i ++)
       {
         my_xid x=info->list[i].get_my_xid();
@@ -1192,10 +1207,10 @@ bool mysql_xa_recover(THD *thd)
   thd:           the thread handle of the current connection
   return value:  always 0
 */
-static my_bool release_temporary_latches(THD *thd, st_plugin_int *plugin,
+static my_bool release_temporary_latches(THD *thd, plugin_ref plugin,
                                  void *unused)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
 
   if (hton->state == SHOW_OPTION_YES && hton->release_temporary_latches)
     hton->release_temporary_latches(hton, thd);
@@ -1318,10 +1333,10 @@ int ha_release_savepoint(THD *thd, SAVEPOINT *sv)
 }
 
 
-static my_bool snapshot_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool snapshot_handlerton(THD *thd, plugin_ref plugin,
                                    void *arg)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES &&
       hton->start_consistent_snapshot)
   {
@@ -1349,10 +1364,10 @@ int ha_start_consistent_snapshot(THD *thd)
 }
 
 
-static my_bool flush_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool flush_handlerton(THD *thd, plugin_ref plugin,
                                 void *arg)
 {
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->flush_logs && 
       hton->flush_logs(hton))
     return TRUE;
@@ -1397,7 +1412,7 @@ int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
 
   /* DB_TYPE_UNKNOWN is used in ALTER TABLE when renaming only .frm files */
   if (table_type == NULL ||
-      ! (file=get_new_handler(&dummy_share, thd->mem_root, table_type)))
+      ! (file=get_new_handler((TABLE_SHARE*)0, thd->mem_root, table_type)))
     DBUG_RETURN(ENOENT);
 
   if (lower_case_table_names == 2 && !(file->ha_table_flags() & HA_FILE_BASED))
@@ -1438,6 +1453,8 @@ int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
     dummy_share.table_name.length= strlen(alias);
     dummy_table.alias= alias;
 
+    file->table_share= &dummy_share;
+    file->table= &dummy_table;
     file->print_error(error, 0);
     strmake(new_error, thd->net.last_error, sizeof(buff)-1);
 
@@ -1458,7 +1475,7 @@ int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
 ****************************************************************************/
 handler *handler::clone(MEM_ROOT *mem_root)
 {
-  handler *new_handler= get_new_handler(table->s, mem_root, table->s->db_type);
+  handler *new_handler= get_new_handler(table->s, mem_root, table->s->db_type());
   if (new_handler && !new_handler->ha_open(table,
                                            table->s->normalized_path.str,
                                            table->db_stat,
@@ -1474,6 +1491,26 @@ void handler::ha_statistic_increment(ulong SSV::*offset) const
   statistic_increment(table->in_use->status_var.*offset, &LOCK_status);
 }
 
+enum enum_tx_isolation  handler::ha_tx_isolation(void) const
+{
+  return (enum_tx_isolation) ha_thd()->variables.tx_isolation;
+}
+
+uint handler::ha_sql_command(void) const
+{
+  return (uint) ha_thd()->lex->sql_command;
+}
+
+void **handler::ha_data(void) const
+{
+  return (void **) ha_thd()->ha_data + ht->slot;
+}
+
+THD *handler::ha_thd(void) const
+{
+  return (table && table->in_use) ? table->in_use : current_thd;
+}
+
 
 bool handler::check_if_log_table_locking_is_allowed(uint sql_command,
                                                     ulong type, TABLE *table)
@@ -1567,8 +1604,7 @@ int handler::read_first_row(byte * buf, uint primary_key)
   register int error;
   DBUG_ENTER("handler::read_first_row");
 
-  statistic_increment(table->in_use->status_var.ha_read_first_count,
-                      &LOCK_status);
+  ha_statistic_increment(&SSV::ha_read_first_count);
 
   /*
     If there is very few deleted rows in the table, find the first row by
@@ -2785,11 +2821,11 @@ struct st_discover_args
   uint* frmlen;
 };
 
-static my_bool discover_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool discover_handlerton(THD *thd, plugin_ref plugin,
                                    void *arg)
 {
   st_discover_args *vargs= (st_discover_args *)arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->discover &&
       (!(hton->discover(hton, thd, vargs->db, vargs->name, 
                         vargs->frmblob, 
@@ -2834,11 +2870,11 @@ struct st_find_files_args
   List<char> *files;
 };
 
-static my_bool find_files_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool find_files_handlerton(THD *thd, plugin_ref plugin,
                                    void *arg)
 {
   st_find_files_args *vargs= (st_find_files_args *)arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
 
 
   if (hton->state == SHOW_OPTION_YES && hton->find_files)
@@ -2881,11 +2917,11 @@ struct st_table_exists_in_engine_args
   const char *name;
 };
 
-static my_bool table_exists_in_engine_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool table_exists_in_engine_handlerton(THD *thd, plugin_ref plugin,
                                    void *arg)
 {
   st_table_exists_in_engine_args *vargs= (st_table_exists_in_engine_args *)arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
 
   if (hton->state == SHOW_OPTION_YES && hton->table_exists_in_engine)
     if ((hton->table_exists_in_engine(hton, thd, vargs->db, vargs->name)) == 1)
@@ -2929,10 +2965,10 @@ struct binlog_func_st
 /** @brief
   Listing handlertons first to avoid recursive calls and deadlock
 */
-static my_bool binlog_func_list(THD *thd, st_plugin_int *plugin, void *arg)
+static my_bool binlog_func_list(THD *thd, plugin_ref plugin, void *arg)
 {
   hton_list_st *hton_list= (hton_list_st *)arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->binlog_func)
   {
     uint sz= hton_list->sz;
@@ -3019,10 +3055,10 @@ static my_bool binlog_log_query_handlerton2(THD *thd,
 }
 
 static my_bool binlog_log_query_handlerton(THD *thd,
-                                           st_plugin_int *plugin,
+                                           plugin_ref plugin,
                                            void *args)
 {
-  return binlog_log_query_handlerton2(thd, (handlerton *)plugin->data, args);
+  return binlog_log_query_handlerton2(thd, plugin_data(plugin, handlerton *), args);
 }
 
 void ha_binlog_log_query(THD *thd, handlerton *hton,
@@ -3310,11 +3346,11 @@ int handler::index_read_idx(byte * buf, uint index, const byte * key,
   RETURN VALUE
     pointer		pointer to TYPELIB structure
 */
-static my_bool exts_handlerton(THD *unused, st_plugin_int *plugin,
+static my_bool exts_handlerton(THD *unused, plugin_ref plugin,
                                void *arg)
 {
   List<char> *found_exts= (List<char> *) arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   handler *file;
   if (hton->state == SHOW_OPTION_YES && hton->create &&
       (file= hton->create(hton, (TABLE_SHARE*) 0, current_thd->mem_root)))
@@ -3385,11 +3421,11 @@ static bool stat_print(THD *thd, const char *type, uint type_len,
 }
 
 
-static my_bool showstat_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool showstat_handlerton(THD *thd, plugin_ref plugin,
                                    void *arg)
 {
   enum ha_stat_type stat= *(enum ha_stat_type *) arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if (hton->state == SHOW_OPTION_YES && hton->show_status &&
       hton->show_status(hton, thd, stat_print, stat))
     return TRUE;
diff --git a/sql/handler.h b/sql/handler.h
index 82970cc1ac6..fbdd48fcc6d 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -876,6 +876,8 @@ public:
 class handler :public Sql_alloc
 {
   friend class ha_partition;
+  friend int ha_delete_table(THD*,handlerton*,const char*,const char*,
+                             const char*,bool);
 
  protected:
   struct st_table_share *table_share;   /* The table definition */
@@ -894,7 +896,12 @@ class handler :public Sql_alloc
   virtual int rnd_init(bool scan) =0;
   virtual int rnd_end() { return 0; }
   virtual ulonglong table_flags(void) const =0;
+
   void ha_statistic_increment(ulong SSV::*offset) const;
+  enum enum_tx_isolation ha_tx_isolation(void) const;
+  uint ha_sql_command(void) const;
+  void **ha_data(void) const;
+  THD *ha_thd(void) const;
 
   ha_rows estimation_rows_to_insert;
   virtual void start_bulk_insert(ha_rows rows) {}
@@ -1626,9 +1633,9 @@ extern ulong total_ha, total_ha_2pc;
 
 /* lookups */
 handlerton *ha_default_handlerton(THD *thd);
-handlerton *ha_resolve_by_name(THD *thd, const LEX_STRING *name);
+plugin_ref ha_resolve_by_name(THD *thd, const LEX_STRING *name);
+plugin_ref ha_lock_engine(THD *thd, handlerton *hton);
 handlerton *ha_resolve_by_legacy_type(THD *thd, enum legacy_db_type db_type);
-const char *ha_get_storage_engine(enum legacy_db_type db_type);
 handler *get_new_handler(TABLE_SHARE *share, MEM_ROOT *alloc,
                          handlerton *db_type);
 handlerton *ha_checktype(THD *thd, enum legacy_db_type database_type,
diff --git a/sql/item_func.cc b/sql/item_func.cc
index aa344a343de..8272d15e5ae 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4887,7 +4887,7 @@ Item *get_system_var(THD *thd, enum_var_type var_type, LEX_STRING name,
     component_name= &component;			// Empty string
   }
 
-  if (!(var= find_sys_var(base_name->str, base_name->length)))
+  if (!(var= find_sys_var(thd, base_name->str, base_name->length)))
     return 0;
   if (component.str)
   {
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index f34fc008186..27c48604907 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -2469,7 +2469,7 @@ bool Item_sum_count_distinct::setup(THD *thd)
   table->file->extra(HA_EXTRA_NO_ROWS);		// Don't update rows
   table->no_rows=1;
 
-  if (table->s->db_type == heap_hton)
+  if (table->s->db_type() == heap_hton)
   {
     /*
       No blobs, otherwise it would have been MyISAM: set up a compare
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index bf6bd374ef8..4968fde7f64 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -546,11 +546,6 @@ inline THD *_current_thd(void)
 }
 #define current_thd _current_thd()
 
-/* below functions are required for plugins as THD class is opaque */
-my_bool thd_in_lock_tables(const THD *thd);
-my_bool thd_tablespace_op(const THD *thd);
-const char *thd_proc_info(THD *thd, const char *info);
-void **thd_ha_data(const THD *thd, const struct handlerton *hton);
 
 /*
   External variables
@@ -1098,6 +1093,7 @@ int add_status_vars(SHOW_VAR *list);
 void remove_status_vars(SHOW_VAR *list);
 void init_status_vars();
 void free_status_vars();
+void reset_status_vars();
 
 /* information schema */
 extern LEX_STRING information_schema_name;
@@ -1659,6 +1655,7 @@ extern pthread_mutex_t LOCK_server_started;
 extern pthread_cond_t COND_server_started;
 extern int mysqld_server_started;
 extern rw_lock_t LOCK_grant, LOCK_sys_init_connect, LOCK_sys_init_slave;
+extern rw_lock_t LOCK_system_variables_hash;
 extern pthread_cond_t COND_refresh, COND_thread_count, COND_manager;
 extern pthread_cond_t COND_global_read_lock;
 extern pthread_attr_t connection_attrib;
@@ -1667,7 +1664,7 @@ extern I_List<NAMED_LIST> key_caches;
 extern MY_BITMAP temp_pool;
 extern String my_empty_string;
 extern const String my_null_string;
-extern SHOW_VAR init_vars[], status_vars[], internal_vars[];
+extern SHOW_VAR status_vars[];
 extern struct system_variables global_system_variables;
 extern struct system_variables max_system_variables;
 extern struct system_status_var global_status_var;
@@ -1690,11 +1687,6 @@ extern TYPELIB log_output_typelib;
 
 /* optional things, have_* variables */
 
-extern SHOW_COMP_OPTION have_innodb;
-extern SHOW_COMP_OPTION have_csv_db;
-extern SHOW_COMP_OPTION have_ndbcluster;
-extern SHOW_COMP_OPTION have_partition_db;
-
 extern handlerton *partition_hton;
 extern handlerton *myisam_hton;
 extern handlerton *heap_hton;
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index a6525c1c78c..c1ba05e24bd 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -29,22 +29,13 @@
 
 #include "rpl_injector.h"
 
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-#define OPT_INNODB_DEFAULT 1
-#else
-#define OPT_INNODB_DEFAULT 0
-#endif
-#define OPT_BDB_DEFAULT 0
 #ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
-#define OPT_NDBCLUSTER_DEFAULT 0
 #if defined(NOT_ENOUGH_TESTED) \
   && defined(NDB_SHM_TRANSPORTER) && MYSQL_VERSION_ID >= 50000
 #define OPT_NDB_SHM_DEFAULT 1
 #else
 #define OPT_NDB_SHM_DEFAULT 0
 #endif
-#else
-#define OPT_NDBCLUSTER_DEFAULT 0
 #endif
 
 #ifndef DEFAULT_SKIP_THREAD_PRIORITY
@@ -323,7 +314,6 @@ static bool lower_case_table_names_used= 0;
 static bool volatile select_thread_in_use, signal_thread_in_use;
 static bool volatile ready_to_exit;
 static my_bool opt_debugging= 0, opt_external_locking= 0, opt_console= 0;
-static my_bool opt_ndbcluster;
 static my_bool opt_short_log_format= 0;
 static uint kill_cached_threads, wake_thread;
 static ulong killed_threads, thread_created;
@@ -366,7 +356,6 @@ my_bool opt_local_infile, opt_slave_compressed_protocol;
 my_bool opt_safe_user_create = 0, opt_no_mix_types = 0;
 my_bool opt_show_slave_auth_info, opt_sql_bin_update = 0;
 my_bool opt_log_slave_updates= 0;
-my_bool	opt_innodb;
 
 /*
   Legacy global handlerton. These will be removed (please do not add more).
@@ -375,44 +364,6 @@ handlerton *heap_hton;
 handlerton *myisam_hton;
 handlerton *partition_hton;
 
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-extern ulong innobase_fast_shutdown;
-extern ulong innobase_large_page_size;
-extern char *innobase_home, *innobase_tmpdir, *innobase_logdir;
-extern long innobase_lock_scan_time;
-extern long innobase_mirrored_log_groups, innobase_log_files_in_group;
-extern longlong innobase_log_file_size;
-extern long innobase_log_buffer_size;
-extern longlong innobase_buffer_pool_size;
-extern long innobase_additional_mem_pool_size;
-extern long innobase_file_io_threads, innobase_lock_wait_timeout;
-extern long innobase_force_recovery;
-extern long innobase_open_files;
-extern char *innobase_data_home_dir, *innobase_data_file_path;
-extern char *innobase_log_group_home_dir, *innobase_log_arch_dir;
-extern char *innobase_unix_file_flush_method;
-/* The following variables have to be my_bool for SHOW VARIABLES to work */
-extern my_bool innobase_log_archive,
-               innobase_use_doublewrite,
-               innobase_use_checksums,
-               innobase_use_large_pages,
-               innobase_use_native_aio,
-               innobase_file_per_table, innobase_locks_unsafe_for_binlog,
-               innobase_rollback_on_timeout,
-               innobase_create_status_file;
-extern "C" {
-extern ulong srv_max_buf_pool_modified_pct;
-extern ulong srv_max_purge_lag;
-extern ulong srv_auto_extend_increment;
-extern ulong srv_n_spin_wait_rounds;
-extern ulong srv_n_free_tickets_to_enter;
-extern ulong srv_thread_sleep_delay;
-extern ulong srv_thread_concurrency;
-extern ulong srv_commit_concurrency;
-extern ulong srv_flush_log_at_trx_commit;
-}
-#endif
-
 #ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
 const char *opt_ndbcluster_connectstring= 0;
 const char *opt_ndb_connectstring= 0;
@@ -594,6 +545,7 @@ pthread_mutex_t LOCK_prepared_stmt_count;
 pthread_mutex_t LOCK_des_key_file;
 #endif
 rw_lock_t	LOCK_grant, LOCK_sys_init_connect, LOCK_sys_init_slave;
+rw_lock_t	LOCK_system_variables_hash;
 pthread_cond_t COND_refresh, COND_thread_count, COND_global_read_lock;
 pthread_t signal_thread;
 pthread_attr_t connection_attrib;
@@ -625,6 +577,7 @@ static ulong opt_specialflag, opt_myisam_block_size;
 static char *opt_update_logname, *opt_binlog_index_name;
 static char *opt_tc_heuristic_recover;
 static char *mysql_home_ptr, *pidfile_name_ptr;
+static int defaults_argc;
 static char **defaults_argv;
 static char *opt_bin_logname;
 
@@ -716,7 +669,9 @@ struct st_VioSSLFd *ssl_acceptor_fd;
 
 pthread_handler_t signal_hand(void *arg);
 static void mysql_init_variables(void);
-static void get_options(int argc,char **argv);
+static void get_options(int *argc,char **argv);
+static my_bool get_one_option(int, const struct my_option *, char *);
+static void usage(void);
 static void set_server_version(void);
 static int init_thread_environment();
 static char *get_relative_path(const char *path);
@@ -1161,6 +1116,8 @@ void unireg_end(void)
 extern "C" void unireg_abort(int exit_code)
 {
   DBUG_ENTER("unireg_abort");
+  if (opt_help)
+    usage();
   if (exit_code)
     sql_print_error("Aborting\n");
   clean_up(exit_code || !opt_bootstrap); /* purecov: inspected */
@@ -1347,6 +1304,7 @@ static void clean_up_mutexes()
   (void) rwlock_destroy(&LOCK_sys_init_connect);
   (void) rwlock_destroy(&LOCK_sys_init_slave);
   (void) pthread_mutex_destroy(&LOCK_global_system_variables);
+  (void) rwlock_destroy(&LOCK_system_variables_hash);
   (void) pthread_mutex_destroy(&LOCK_global_read_lock);
   (void) pthread_mutex_destroy(&LOCK_uuid_generator);
   (void) pthread_mutex_destroy(&LOCK_prepared_stmt_count);
@@ -2753,7 +2711,8 @@ static int init_common_variables(const char *conf_file_name, int argc,
 
   load_defaults(conf_file_name, groups, &argc, &argv);
   defaults_argv=argv;
-  get_options(argc,argv);
+  defaults_argc=argc;
+  get_options(&defaults_argc, defaults_argv);
   set_server_version();
 
   DBUG_PRINT("info",("%s  Ver %s for %s on %s\n",my_progname,
@@ -2765,10 +2724,6 @@ static int init_common_variables(const char *conf_file_name, int argc,
   {
       my_use_large_pages= 1;
       my_large_page_size= opt_large_page_size;
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-      innobase_use_large_pages= 1;
-      innobase_large_page_size= opt_large_page_size;
-#endif
   }
 #endif /* HAVE_LARGE_PAGES */
 
@@ -2831,7 +2786,12 @@ static int init_common_variables(const char *conf_file_name, int argc,
   if (item_create_init())
     return 1;
   item_init();
-  set_var_init();
+  if (set_var_init())
+    return 1;
+#ifdef HAVE_REPLICATION
+  if (init_replication_sys_vars())
+    return 1;
+#endif
   mysys_uses_curses=0;
 #ifdef USE_REGEX
   my_regex_init(&my_charset_latin1);
@@ -2984,6 +2944,7 @@ static int init_thread_environment()
   (void) pthread_mutex_init(&LOCK_user_conn, MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_active_mi, MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_global_system_variables, MY_MUTEX_INIT_FAST);
+  (void) my_rwlock_init(&LOCK_system_variables_hash, NULL);
   (void) pthread_mutex_init(&LOCK_global_read_lock, MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_prepared_stmt_count, MY_MUTEX_INIT_FAST);
   (void) pthread_mutex_init(&LOCK_uuid_generator, MY_MUTEX_INIT_FAST);
@@ -3319,10 +3280,42 @@ server.");
     using_update_log=1;
   }
 
-  if (plugin_init(opt_bootstrap))
+  if (plugin_init(&defaults_argc, defaults_argv, 
+                  (opt_noacl ? PLUGIN_INIT_SKIP_PLUGIN_TABLE : 0) |
+                  (opt_help ? PLUGIN_INIT_SKIP_INITIALIZATION : 0)))
   {
-    sql_print_error("Failed to init plugins.");
-    return 1;
+    sql_print_error("Failed to initialize plugins.");
+    unireg_abort(1);
+  }
+
+  if (opt_help)
+    unireg_abort(0);
+
+  /* we do want to exit if there are any other unknown options */
+  if (defaults_argc > 1)
+  {
+    int ho_error;
+    struct my_option no_opts[] =
+    {
+      {0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
+    };
+    /*
+      We need to eat any 'loose' arguments first before we conclude
+      that there are unprocessed options
+    */
+    my_getopt_skip_unknown= 0;
+    
+    if ((ho_error= handle_options(&defaults_argc, &defaults_argv, no_opts,
+                                  get_one_option)))
+      unireg_abort(ho_error);
+    
+    if (defaults_argc)
+    {
+      fprintf(stderr, "%s: Too many arguments (first extra is '%s').\n"
+              "Use --verbose --help to get a list of available options\n", 
+              my_progname, *defaults_argv);
+      unireg_abort(1);
+    }
   }
 
   /* We have to initialize the storage engines before CSV logging */
@@ -3353,7 +3346,8 @@ server.");
   else
   {
     /* fall back to the log files if tables are not present */
-    if (have_csv_db == SHOW_OPTION_NO)
+    LEX_STRING csv_name={C_STRING_WITH_LEN("csv")};
+    if (!plugin_is_ready(&csv_name, MYSQL_STORAGE_ENGINE_PLUGIN))
     {
       /* purecov: begin inspected */
       sql_print_error("CSV engine is not present, falling back to the "
@@ -3373,11 +3367,16 @@ server.");
   /*
     Check that the default storage engine is actually available.
   */
+  if (default_storage_engine_str)
   {
     LEX_STRING name= { default_storage_engine_str,
                        strlen(default_storage_engine_str) };
-    handlerton *hton= ha_resolve_by_name(0, &name);
-    if (hton == NULL)
+    plugin_ref plugin;
+    handlerton *hton;
+    
+    if ((plugin= ha_resolve_by_name(0, &name)))
+      hton= plugin_data(plugin, handlerton*);
+    else
     {
       sql_print_error("Unknown/unsupported table type: %s",
                       default_storage_engine_str);
@@ -3391,9 +3390,17 @@ server.");
                         default_storage_engine_str);
         unireg_abort(1);
       }
-      hton= myisam_hton;
+      DBUG_ASSERT(global_system_variables.table_plugin);
+    }
+    else
+    {
+      /*
+        Need to unlock as global_system_variables.table_plugin 
+        was acquired during plugin_init()
+      */
+      plugin_unlock(0, global_system_variables.table_plugin);
+      global_system_variables.table_plugin= plugin;
     }
-    global_system_variables.table_type= hton;
   }
 
   tc_log= (total_ha_2pc > 1 ? (opt_bin_log  ?
@@ -4797,11 +4804,6 @@ enum options_mysqld
   OPT_STORAGE_ENGINE,          OPT_INIT_FILE,
   OPT_DELAY_KEY_WRITE_ALL,     OPT_SLOW_QUERY_LOG,
   OPT_DELAY_KEY_WRITE,	       OPT_CHARSETS_DIR,
-  OPT_BDB_HOME,                OPT_BDB_LOG,
-  OPT_BDB_TMP,                 OPT_BDB_SYNC,
-  OPT_BDB_LOCK,                OPT_BDB,
-  OPT_BDB_NO_RECOVER,          OPT_BDB_SHARED,
-  OPT_BDB_DATA_DIRECT,         OPT_BDB_LOG_DIRECT,
   OPT_MASTER_HOST,             OPT_MASTER_USER,
   OPT_MASTER_PASSWORD,         OPT_MASTER_PORT,
   OPT_MASTER_INFO_FILE,        OPT_MASTER_CONNECT_RETRY,
@@ -4820,28 +4822,14 @@ enum options_mysqld
   OPT_WANT_CORE,               OPT_CONCURRENT_INSERT,
   OPT_MEMLOCK,                 OPT_MYISAM_RECOVER,
   OPT_REPLICATE_REWRITE_DB,    OPT_SERVER_ID,
-  OPT_SKIP_SLAVE_START,        OPT_SKIP_INNOBASE,
+  OPT_SKIP_SLAVE_START,        OPT_SAFE_SHOW_DB, 
   OPT_SAFEMALLOC_MEM_LIMIT,    OPT_REPLICATE_DO_TABLE,
   OPT_REPLICATE_IGNORE_TABLE,  OPT_REPLICATE_WILD_DO_TABLE,
   OPT_REPLICATE_WILD_IGNORE_TABLE, OPT_REPLICATE_SAME_SERVER_ID,
   OPT_DISCONNECT_SLAVE_EVENT_COUNT, OPT_TC_HEURISTIC_RECOVER,
   OPT_ABORT_SLAVE_EVENT_COUNT,
-  OPT_INNODB_DATA_HOME_DIR,
-  OPT_INNODB_DATA_FILE_PATH,
-  OPT_INNODB_LOG_GROUP_HOME_DIR,
-  OPT_INNODB_LOG_ARCH_DIR,
-  OPT_INNODB_LOG_ARCHIVE,
-  OPT_INNODB_FLUSH_LOG_AT_TRX_COMMIT,
-  OPT_INNODB_FLUSH_METHOD,
-  OPT_INNODB_DOUBLEWRITE,
-  OPT_INNODB_CHECKSUMS,
-  OPT_INNODB_FAST_SHUTDOWN,
-  OPT_INNODB_FILE_PER_TABLE, OPT_CRASH_BINLOG_INNODB,
-  OPT_INNODB_LOCKS_UNSAFE_FOR_BINLOG,
   OPT_LOG_BIN_TRUST_FUNCTION_CREATORS,
-  OPT_SAFE_SHOW_DB, OPT_INNODB_SAFE_BINLOG,
-  OPT_INNODB, OPT_ISAM,
-  OPT_ENGINE_CONDITION_PUSHDOWN, OPT_NDBCLUSTER, OPT_NDB_CONNECTSTRING, 
+  OPT_ENGINE_CONDITION_PUSHDOWN, OPT_NDB_CONNECTSTRING, 
   OPT_NDB_USE_EXACT_COUNT, OPT_NDB_USE_TRANSACTIONS,
   OPT_NDB_FORCE_SEND, OPT_NDB_AUTOINCREMENT_PREFETCH_SZ,
   OPT_NDB_SHM, OPT_NDB_OPTIMIZED_NODE_SELECTION, OPT_NDB_CACHE_CHECK_TIME,
@@ -4904,33 +4892,6 @@ enum options_mysqld
   OPT_THREAD_CONCURRENCY, OPT_THREAD_CACHE_SIZE,
   OPT_TMP_TABLE_SIZE, OPT_THREAD_STACK,
   OPT_WAIT_TIMEOUT, OPT_MYISAM_REPAIR_THREADS,
-  OPT_INNODB_MIRRORED_LOG_GROUPS,
-  OPT_INNODB_LOG_FILES_IN_GROUP,
-  OPT_INNODB_LOG_FILE_SIZE,
-  OPT_INNODB_LOG_BUFFER_SIZE,
-  OPT_INNODB_BUFFER_POOL_SIZE,
-  OPT_INNODB_BUFFER_POOL_AWE_MEM_MB,
-  OPT_INNODB_ADDITIONAL_MEM_POOL_SIZE,
-  OPT_INNODB_MAX_PURGE_LAG,
-  OPT_INNODB_FILE_IO_THREADS,
-  OPT_INNODB_LOCK_WAIT_TIMEOUT,
-  OPT_INNODB_THREAD_CONCURRENCY,
-  OPT_INNODB_COMMIT_CONCURRENCY,
-  OPT_INNODB_FORCE_RECOVERY,
-  OPT_INNODB_STATUS_FILE,
-  OPT_INNODB_MAX_DIRTY_PAGES_PCT,
-  OPT_INNODB_TABLE_LOCKS,
-  OPT_INNODB_SUPPORT_XA,
-  OPT_INNODB_OPEN_FILES,
-  OPT_INNODB_AUTOEXTEND_INCREMENT,
-  OPT_INNODB_SYNC_SPIN_LOOPS,
-  OPT_INNODB_CONCURRENCY_TICKETS,
-  OPT_INNODB_THREAD_SLEEP_DELAY,
-  OPT_BDB_CACHE_SIZE,
-  OPT_BDB_CACHE_PARTS,
-  OPT_BDB_LOG_BUFFER_SIZE,
-  OPT_BDB_MAX_LOCK,
-  OPT_BDB_REGION_SIZE,
   OPT_ERROR_LOG_FILE,
   OPT_DEFAULT_WEEK_FORMAT,
   OPT_RANGE_ALLOC_BLOCK_SIZE, OPT_ALLOW_SUSPICIOUS_UDFS,
@@ -4940,7 +4901,6 @@ enum options_mysqld
   OPT_SYNC_REPLICATION,
   OPT_SYNC_REPLICATION_SLAVE_ID,
   OPT_SYNC_REPLICATION_TIMEOUT,
-  OPT_BDB_NOSYNC,
   OPT_ENABLE_SHARED_MEMORY,
   OPT_SHARED_MEMORY_BASE_NAME,
   OPT_OLD_PASSWORDS,
@@ -4970,12 +4930,12 @@ enum options_mysqld
   OPT_OLD_STYLE_USER_LIMITS,
   OPT_LOG_SLOW_ADMIN_STATEMENTS,
   OPT_TABLE_LOCK_WAIT_TIMEOUT,
+  OPT_PLUGIN_LOAD,
   OPT_PLUGIN_DIR,
   OPT_LOG_OUTPUT,
   OPT_PORT_OPEN_TIMEOUT,
   OPT_GENERAL_LOG,
   OPT_SLOW_LOG,
-  OPT_MERGE,
   OPT_THREAD_HANDLING,
   OPT_INNODB_ROLLBACK_ON_TIMEOUT
 };
@@ -5193,94 +5153,6 @@ Disable with --skip-large-pages.",
   {"init-slave", OPT_INIT_SLAVE, "Command(s) that are executed when a slave connects to this master",
    (gptr*) &opt_init_slave, (gptr*) &opt_init_slave, 0, GET_STR_ALLOC,
    REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb", OPT_INNODB, "Enable InnoDB (if this version of MySQL supports it). \
-Disable with --skip-innodb (will save memory).",
-   (gptr*) &opt_innodb, (gptr*) &opt_innodb, 0, GET_BOOL, NO_ARG, OPT_INNODB_DEFAULT, 0, 0,
-   0, 0, 0},
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  {"innodb_checksums", OPT_INNODB_CHECKSUMS, "Enable InnoDB checksums validation (enabled by default). \
-Disable with --skip-innodb-checksums.", (gptr*) &innobase_use_checksums,
-   (gptr*) &innobase_use_checksums, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},
-#endif
-  {"innodb_data_file_path", OPT_INNODB_DATA_FILE_PATH,
-   "Path to individual files and their sizes.",
-   0, 0, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  {"innodb_data_home_dir", OPT_INNODB_DATA_HOME_DIR,
-   "The common part for InnoDB table spaces.", (gptr*) &innobase_data_home_dir,
-   (gptr*) &innobase_data_home_dir, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0,
-   0},
-  {"innodb_doublewrite", OPT_INNODB_DOUBLEWRITE, "Enable InnoDB doublewrite buffer (enabled by default). \
-Disable with --skip-innodb-doublewrite.", (gptr*) &innobase_use_doublewrite,
-   (gptr*) &innobase_use_doublewrite, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},
-  {"innodb_fast_shutdown", OPT_INNODB_FAST_SHUTDOWN,
-   "Speeds up the shutdown process of the InnoDB storage engine. Possible "
-   "values are 0, 1 (faster)"
-   /*
-     NetWare can't close unclosed files, can't automatically kill remaining
-     threads, etc, so on this OS we disable the crash-like InnoDB shutdown.
-   */
-#ifndef __NETWARE__
-   " or 2 (fastest - crash-like)"
-#endif
-   ".",
-   (gptr*) &innobase_fast_shutdown,
-   (gptr*) &innobase_fast_shutdown, 0, GET_ULONG, OPT_ARG, 1, 0,
-   IF_NETWARE(1,2), 0, 0, 0},
-  {"innodb_file_per_table", OPT_INNODB_FILE_PER_TABLE,
-   "Stores each InnoDB table to an .ibd file in the database dir.",
-   (gptr*) &innobase_file_per_table,
-   (gptr*) &innobase_file_per_table, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb_flush_log_at_trx_commit", OPT_INNODB_FLUSH_LOG_AT_TRX_COMMIT,
-   "Set to 0 (write and flush once per second), 1 (write and flush at each commit) or 2 (write at commit, flush once per second).",
-   (gptr*) &srv_flush_log_at_trx_commit,
-   (gptr*) &srv_flush_log_at_trx_commit,
-   0, GET_ULONG, OPT_ARG,  1, 0, 2, 0, 0, 0},
-  {"innodb_flush_method", OPT_INNODB_FLUSH_METHOD,
-   "With which method to flush data.", (gptr*) &innobase_unix_file_flush_method,
-   (gptr*) &innobase_unix_file_flush_method, 0, GET_STR, REQUIRED_ARG, 0, 0, 0,
-   0, 0, 0},
-  {"innodb_locks_unsafe_for_binlog", OPT_INNODB_LOCKS_UNSAFE_FOR_BINLOG,
-   "Force InnoDB to not use next-key locking, to use only row-level locking.",
-   (gptr*) &innobase_locks_unsafe_for_binlog,
-   (gptr*) &innobase_locks_unsafe_for_binlog, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb_log_arch_dir", OPT_INNODB_LOG_ARCH_DIR,
-   "Where full logs should be archived.", (gptr*) &innobase_log_arch_dir,
-   (gptr*) &innobase_log_arch_dir, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb_log_archive", OPT_INNODB_LOG_ARCHIVE,
-   "Set to 1 if you want to have logs archived.", 0, 0, 0, GET_LONG, OPT_ARG,
-   0, 0, 0, 0, 0, 0},
-  {"innodb_log_group_home_dir", OPT_INNODB_LOG_GROUP_HOME_DIR,
-   "Path to InnoDB log files.", (gptr*) &innobase_log_group_home_dir,
-   (gptr*) &innobase_log_group_home_dir, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0,
-   0, 0},
-  {"innodb_max_dirty_pages_pct", OPT_INNODB_MAX_DIRTY_PAGES_PCT,
-   "Percentage of dirty pages allowed in bufferpool.", (gptr*) &srv_max_buf_pool_modified_pct,
-   (gptr*) &srv_max_buf_pool_modified_pct, 0, GET_ULONG, REQUIRED_ARG, 90, 0, 100, 0, 0, 0},
-  {"innodb_max_purge_lag", OPT_INNODB_MAX_PURGE_LAG,
-   "Desired maximum length of the purge queue (0 = no limit)",
-   (gptr*) &srv_max_purge_lag,
-   (gptr*) &srv_max_purge_lag, 0, GET_LONG, REQUIRED_ARG, 0, 0, ~0L,
-   0, 1L, 0},
-  {"innodb_rollback_on_timeout", OPT_INNODB_ROLLBACK_ON_TIMEOUT,
-   "Roll back the complete transaction on lock wait timeout, for 4.x compatibility (disabled by default)",
-   (gptr*) &innobase_rollback_on_timeout, (gptr*) &innobase_rollback_on_timeout,
-   0, GET_BOOL, OPT_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb_status_file", OPT_INNODB_STATUS_FILE,
-   "Enable SHOW INNODB STATUS output in the innodb_status.<pid> file",
-   (gptr*) &innobase_create_status_file, (gptr*) &innobase_create_status_file,
-   0, GET_BOOL, OPT_ARG, 0, 0, 0, 0, 0, 0},
-  {"innodb_support_xa", OPT_INNODB_SUPPORT_XA,
-   "Enable InnoDB support for the XA two-phase commit",
-   (gptr*) &global_system_variables.innodb_support_xa,
-   (gptr*) &global_system_variables.innodb_support_xa,
-   0, GET_BOOL, OPT_ARG, 1, 0, 0, 0, 0, 0},
-  {"innodb_table_locks", OPT_INNODB_TABLE_LOCKS,
-   "Enable InnoDB locking in LOCK TABLES",
-   (gptr*) &global_system_variables.innodb_table_locks,
-   (gptr*) &global_system_variables.innodb_table_locks,
-   0, GET_BOOL, OPT_ARG, 1, 0, 0, 0, 0, 0},
-#endif /* End WITH_INNOBASE_STORAGE_ENGINE */
    {"language", 'L',
    "Client error messages in given language. May be given as a full path.",
    (gptr*) &language_ptr, (gptr*) &language_ptr, 0, GET_STR, REQUIRED_ARG,
@@ -5454,10 +5326,6 @@ master-ssl",
    "Syntax: myisam-recover[=option[,option...]], where option can be DEFAULT, BACKUP, FORCE or QUICK.",
    (gptr*) &myisam_recover_options_str, (gptr*) &myisam_recover_options_str, 0,
    GET_STR, OPT_ARG, 0, 0, 0, 0, 0, 0},
-  {"ndbcluster", OPT_NDBCLUSTER, "Enable NDB Cluster (if this version of MySQL supports it). \
-Disable with --skip-ndbcluster (will save memory).",
-   (gptr*) &opt_ndbcluster, (gptr*) &opt_ndbcluster, 0, GET_BOOL, NO_ARG,
-   OPT_NDBCLUSTER_DEFAULT, 0, 0, 0, 0, 0},
 #ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
   {"ndb-connectstring", OPT_NDB_CONNECTSTRING,
    "Connect string for ndbcluster.",
@@ -5913,84 +5781,6 @@ log and this option does nothing anymore.",
     (gptr*) &global_system_variables.group_concat_max_len,
     (gptr*) &max_system_variables.group_concat_max_len, 0, GET_ULONG,
     REQUIRED_ARG, 1024, 4, (long) ~0, 0, 1, 0},
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  {"innodb_additional_mem_pool_size", OPT_INNODB_ADDITIONAL_MEM_POOL_SIZE,
-   "Size of a memory pool InnoDB uses to store data dictionary information and other internal data structures.",
-   (gptr*) &innobase_additional_mem_pool_size,
-   (gptr*) &innobase_additional_mem_pool_size, 0, GET_LONG, REQUIRED_ARG,
-   1*1024*1024L, 512*1024L, ~0L, 0, 1024, 0},
-  {"innodb_autoextend_increment", OPT_INNODB_AUTOEXTEND_INCREMENT,
-   "Data file autoextend increment in megabytes",
-   (gptr*) &srv_auto_extend_increment,
-   (gptr*) &srv_auto_extend_increment,
-   0, GET_LONG, REQUIRED_ARG, 8L, 1L, 1000L, 0, 1L, 0},
-  {"innodb_buffer_pool_size", OPT_INNODB_BUFFER_POOL_SIZE,
-   "The size of the memory buffer InnoDB uses to cache data and indexes of its tables.",
-   (gptr*) &innobase_buffer_pool_size, (gptr*) &innobase_buffer_pool_size, 0,
-   GET_LL, REQUIRED_ARG, 8*1024*1024L, 1024*1024L, LONGLONG_MAX, 0,
-   1024*1024L, 0},
-  {"innodb_commit_concurrency", OPT_INNODB_COMMIT_CONCURRENCY,
-   "Helps in performance tuning in heavily concurrent environments.",
-   (gptr*) &srv_commit_concurrency, (gptr*) &srv_commit_concurrency,
-   0, GET_LONG, REQUIRED_ARG, 0, 0, 1000, 0, 1, 0},
-  {"innodb_concurrency_tickets", OPT_INNODB_CONCURRENCY_TICKETS,
-   "Number of times a thread is allowed to enter InnoDB within the same \
-    SQL query after it has once got the ticket",
-   (gptr*) &srv_n_free_tickets_to_enter,
-   (gptr*) &srv_n_free_tickets_to_enter,
-   0, GET_LONG, REQUIRED_ARG, 500L, 1L, ~0L, 0, 1L, 0},
-  {"innodb_file_io_threads", OPT_INNODB_FILE_IO_THREADS,
-   "Number of file I/O threads in InnoDB.", (gptr*) &innobase_file_io_threads,
-   (gptr*) &innobase_file_io_threads, 0, GET_LONG, REQUIRED_ARG, 4, 4, 64, 0,
-   1, 0},
-  {"innodb_force_recovery", OPT_INNODB_FORCE_RECOVERY,
-   "Helps to save your data in case the disk image of the database becomes corrupt.",
-   (gptr*) &innobase_force_recovery, (gptr*) &innobase_force_recovery, 0,
-   GET_LONG, REQUIRED_ARG, 0, 0, 6, 0, 1, 0},
-  {"innodb_lock_wait_timeout", OPT_INNODB_LOCK_WAIT_TIMEOUT,
-   "Timeout in seconds an InnoDB transaction may wait for a lock before being rolled back.",
-   (gptr*) &innobase_lock_wait_timeout, (gptr*) &innobase_lock_wait_timeout,
-   0, GET_LONG, REQUIRED_ARG, 50, 1, 1024 * 1024 * 1024, 0, 1, 0},
-  {"innodb_log_buffer_size", OPT_INNODB_LOG_BUFFER_SIZE,
-   "The size of the buffer which InnoDB uses to write log to the log files on disk.",
-   (gptr*) &innobase_log_buffer_size, (gptr*) &innobase_log_buffer_size, 0,
-   GET_LONG, REQUIRED_ARG, 1024*1024L, 256*1024L, ~0L, 0, 1024, 0},
-  {"innodb_log_file_size", OPT_INNODB_LOG_FILE_SIZE,
-   "Size of each log file in a log group.",
-   (gptr*) &innobase_log_file_size, (gptr*) &innobase_log_file_size, 0,
-   GET_LL, REQUIRED_ARG, 5*1024*1024L, 1*1024*1024L, LONGLONG_MAX, 0,
-   1024*1024L, 0},
-  {"innodb_log_files_in_group", OPT_INNODB_LOG_FILES_IN_GROUP,
-   "Number of log files in the log group. InnoDB writes to the files in a circular fashion. Value 3 is recommended here.",
-   (gptr*) &innobase_log_files_in_group, (gptr*) &innobase_log_files_in_group,
-   0, GET_LONG, REQUIRED_ARG, 2, 2, 100, 0, 1, 0},
-  {"innodb_mirrored_log_groups", OPT_INNODB_MIRRORED_LOG_GROUPS,
-   "Number of identical copies of log groups we keep for the database. Currently this should be set to 1.",
-   (gptr*) &innobase_mirrored_log_groups,
-   (gptr*) &innobase_mirrored_log_groups, 0, GET_LONG, REQUIRED_ARG, 1, 1, 10,
-   0, 1, 0},
-  {"innodb_open_files", OPT_INNODB_OPEN_FILES,
-   "How many files at the maximum InnoDB keeps open at the same time.",
-   (gptr*) &innobase_open_files, (gptr*) &innobase_open_files, 0,
-   GET_LONG, REQUIRED_ARG, 300L, 10L, ~0L, 0, 1L, 0},
-  {"innodb_sync_spin_loops", OPT_INNODB_SYNC_SPIN_LOOPS,
-   "Count of spin-loop rounds in InnoDB mutexes",
-   (gptr*) &srv_n_spin_wait_rounds,
-   (gptr*) &srv_n_spin_wait_rounds,
-   0, GET_LONG, REQUIRED_ARG, 20L, 0L, ~0L, 0, 1L, 0},
-  {"innodb_thread_concurrency", OPT_INNODB_THREAD_CONCURRENCY,
-   "Helps in performance tuning in heavily concurrent environments. "
-   "Sets the maximum number of threads allowed inside InnoDB. Value 0"
-   " will disable the thread throttling.",
-   (gptr*) &srv_thread_concurrency, (gptr*) &srv_thread_concurrency,
-   0, GET_LONG, REQUIRED_ARG, 8, 0, 1000, 0, 1, 0},
-  {"innodb_thread_sleep_delay", OPT_INNODB_THREAD_SLEEP_DELAY,
-   "Time of innodb thread sleeping before joining InnoDB queue (usec). Value 0"
-    " disable a sleep",
-   (gptr*) &srv_thread_sleep_delay,
-   (gptr*) &srv_thread_sleep_delay,
-   0, GET_LONG, REQUIRED_ARG, 10000L, 0L, ~0L, 0, 1L, 0},
-#endif /* WITH_INNOBASE_STORAGE_ENGINE */
   {"interactive_timeout", OPT_INTERACTIVE_TIMEOUT,
    "The number of seconds the server waits for activity on an interactive connection before closing it.",
    (gptr*) &global_system_variables.net_interactive_timeout,
@@ -6216,6 +6006,11 @@ The minimum value for this variable is 4096.",
    "Directory for plugins.",
    (gptr*) &opt_plugin_dir_ptr, (gptr*) &opt_plugin_dir_ptr, 0,
    GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
+  {"plugin_load", OPT_PLUGIN_LOAD,
+   "Optional colon separated list of plugins to load, where each plugin is "
+   "identified by name and path to library seperated by an equals.",
+   (gptr*) &opt_plugin_load, (gptr*) &opt_plugin_load, 0,
+   GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0, 0},
    {"preload_buffer_size", OPT_PRELOAD_BUFFER_SIZE,
     "The size of the buffer that is allocated when preloading indexes",
     (gptr*) &global_system_variables.preload_buff_size,
@@ -7015,8 +6810,8 @@ Starts the MySQL database server\n");
   fix_paths();
   set_ports();
 
-  my_print_help(my_long_options);
-  my_print_variables(my_long_options);
+  /* Print out all the options including plugin supplied options */
+  my_print_help_inc_plugins(my_long_options, sizeof(my_long_options)/sizeof(my_option));
 
   puts("\n\
 To see what values a running MySQL server is using, type\n\
@@ -7058,6 +6853,7 @@ static void mysql_init_variables(void)
   mqh_used= 0;
   segfaulted= kill_in_progress= 0;
   cleanup_done= 0;
+  defaults_argc= 0;
   defaults_argv= 0;
   server_id_supplied= 0;
   test_flags= select_errors= dropping_tables= ha_open_options=0;
@@ -7145,7 +6941,7 @@ static void mysql_init_variables(void)
 
   /* Set default values for some option variables */
   default_storage_engine_str= (char*) "MyISAM";
-  global_system_variables.table_type= myisam_hton;
+  global_system_variables.table_plugin= NULL;
   global_system_variables.tx_isolation= ISO_REPEATABLE_READ;
   global_system_variables.select_limit= (ulonglong) HA_POS_ERROR;
   max_system_variables.select_limit=    (ulonglong) HA_POS_ERROR;
@@ -7166,36 +6962,13 @@ static void mysql_init_variables(void)
 			     "d:t:i:o,/tmp/mysqld.trace");
 #endif
   opt_error_log= IF_WIN(1,0);
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  have_innodb= SHOW_OPTION_YES;
-#else
-  have_innodb= SHOW_OPTION_NO;
-#endif
-#ifdef WITH_CSV_STORAGE_ENGINE
-  have_csv_db= SHOW_OPTION_YES;
-#else
-  have_csv_db= SHOW_OPTION_NO;
-#endif
 #ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
-    have_ndbcluster= SHOW_OPTION_DISABLED;
-#else
-    have_ndbcluster= SHOW_OPTION_NO;
-#endif
-#ifdef WITH_PARTITION_STORAGE_ENGINE
-    have_partition_db= SHOW_OPTION_YES;
-#else
-    have_partition_db= SHOW_OPTION_NO;
-#endif
-#ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
-  have_ndbcluster=SHOW_OPTION_DISABLED;
   global_system_variables.ndb_index_stat_enable=FALSE;
   max_system_variables.ndb_index_stat_enable=TRUE;
   global_system_variables.ndb_index_stat_cache_entries=32;
   max_system_variables.ndb_index_stat_cache_entries=~0L;
   global_system_variables.ndb_index_stat_update_freq=20;
   max_system_variables.ndb_index_stat_update_freq=~0L;
-#else
-  have_ndbcluster=SHOW_OPTION_NO;
 #endif
 #ifdef HAVE_OPENSSL
   have_openssl=SHOW_OPTION_YES;
@@ -7655,17 +7428,6 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
     global_system_variables.tx_isolation= (type-1);
     break;
   }
-  case OPT_MERGE:
-  case OPT_BDB:
-    break;
-  case OPT_NDBCLUSTER:
-#ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
-    if (opt_ndbcluster)
-      have_ndbcluster= SHOW_OPTION_YES;
-    else
-      have_ndbcluster= SHOW_OPTION_DISABLED;
-#endif
-    break;
 #ifdef WITH_NDBCLUSTER_STORAGE_ENGINE
   case OPT_NDB_MGMD:
   case OPT_NDB_NODEID:
@@ -7713,24 +7475,6 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
       ndb_extra_logging= atoi(argument);
     break;
 #endif
-  case OPT_INNODB:
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-    if (opt_innodb)
-      have_innodb= SHOW_OPTION_YES;
-    else
-      have_innodb= SHOW_OPTION_DISABLED;
-#endif
-    break;
-  case OPT_INNODB_DATA_FILE_PATH:
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-    innobase_data_file_path= argument;
-#endif
-    break;
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  case OPT_INNODB_LOG_ARCHIVE:
-    innobase_log_archive= argument ? test(atoi(argument)) : 1;
-    break;
-#endif /* WITH_INNOBASE_STORAGE_ENGINE */
   case OPT_MYISAM_RECOVER:
   {
     if (!argument || !argument[0])
@@ -7884,7 +7628,7 @@ static void option_error_reporter(enum loglevel level, const char *format, ...)
 }
 
 
-static void get_options(int argc,char **argv)
+static void get_options(int *argc,char **argv)
 {
   int ho_error;
 
@@ -7892,34 +7636,20 @@ static void get_options(int argc,char **argv)
   strmake(def_ft_boolean_syntax, ft_boolean_syntax,
 	  sizeof(ft_boolean_syntax)-1);
   my_getopt_error_reporter= option_error_reporter;
-  if ((ho_error= handle_options(&argc, &argv, my_long_options,
+
+  /* Skip unknown options so that they may be processed later by plugins */
+  my_getopt_skip_unknown= TRUE;
+
+  if ((ho_error= handle_options(argc, &argv, my_long_options,
                                 get_one_option)))
     exit(ho_error);
+  (*argc)++; /* add back one for the progname handle_options removes */
+             /* no need to do this for argv as we are discarding it. */
 
-#ifndef WITH_NDBCLUSTER_STORAGE_ENGINE
-  if (opt_ndbcluster)
-    sql_print_warning("this binary does not contain NDBCLUSTER storage engine");
-#endif
-#ifndef WITH_INNOBASE_STORAGE_ENGINE
-  if (opt_innodb)
-    sql_print_warning("this binary does not contain INNODB storage engine");
-#endif
   if ((opt_log_slow_admin_statements || opt_log_queries_not_using_indexes) &&
       !opt_slow_log)
     sql_print_warning("options --log-slow-admin-statements and --log-queries-not-using-indexes have no effect if --log-slow-queries is not set");
 
-  if (argc > 0)
-  {
-    fprintf(stderr, "%s: Too many arguments (first extra is '%s').\nUse --help to get a list of available options\n", my_progname, *argv);
-    /* FIXME add EXIT_TOO_MANY_ARGUMENTS to "mysys_err.h" and return that code? */
-    exit(1);
-  }
-
-  if (opt_help)
-  {
-    usage();
-    exit(0);
-  }
 #if defined(HAVE_BROKEN_REALPATH)
   my_use_symdir=0;
   my_disable_symlinks=1;
@@ -8238,12 +7968,7 @@ void refresh_status(THD *thd)
   bzero((char*) &thd->status_var, sizeof(thd->status_var));
 
   /* Reset some global variables */
-  for (SHOW_VAR *ptr= status_vars; ptr->name; ptr++)
-  {
-    /* Note that SHOW_LONG_NOFLUSH variables are not reset */
-    if (ptr->type == SHOW_LONG)
-      *(ulong*) ptr->value= 0;
-  }
+  reset_status_vars();
 
   /* Reset the counters of all key caches (default and named). */
   process_key_caches(reset_key_cache_counters);
@@ -8262,50 +7987,9 @@ void refresh_status(THD *thd)
 
 
 /*****************************************************************************
-  Instantiate have_xyx for missing storage engines
+  Instantiate variables for missing storage engines
+  This section should go away soon
 *****************************************************************************/
-#undef have_innodb
-#undef have_ndbcluster
-#undef have_csv_db
-
-SHOW_COMP_OPTION have_innodb= SHOW_OPTION_NO;
-SHOW_COMP_OPTION have_ndbcluster= SHOW_OPTION_NO;
-SHOW_COMP_OPTION have_csv_db= SHOW_OPTION_NO;
-SHOW_COMP_OPTION have_partition_db= SHOW_OPTION_NO;
-
-#ifndef WITH_INNOBASE_STORAGE_ENGINE
-uint innobase_flush_log_at_trx_commit;
-ulong innobase_fast_shutdown;
-long innobase_mirrored_log_groups, innobase_log_files_in_group;
-longlong innobase_log_file_size;
-long innobase_log_buffer_size;
-longlong innobase_buffer_pool_size;
-long innobase_additional_mem_pool_size;
-long innobase_file_io_threads, innobase_lock_wait_timeout;
-long innobase_force_recovery;
-long innobase_open_files;
-char *innobase_data_home_dir, *innobase_data_file_path;
-char *innobase_log_group_home_dir, *innobase_log_arch_dir;
-char *innobase_unix_file_flush_method;
-my_bool innobase_log_archive,
-        innobase_use_doublewrite,
-        innobase_use_checksums,
-        innobase_file_per_table,
-        innobase_locks_unsafe_for_binlog,
-        innobase_rollback_on_timeout;
-
-extern "C" {
-ulong srv_max_buf_pool_modified_pct;
-ulong srv_max_purge_lag;
-ulong srv_auto_extend_increment;
-ulong srv_n_spin_wait_rounds;
-ulong srv_n_free_tickets_to_enter;
-ulong srv_thread_sleep_delay;
-ulong srv_thread_concurrency;
-ulong srv_commit_concurrency;
-}
-
-#endif
 
 #ifndef WITH_NDBCLUSTER_STORAGE_ENGINE
 ulong ndb_cache_check_time;
diff --git a/sql/set_var.cc b/sql/set_var.cc
index ad5559165f3..8a51a0f2e62 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -58,39 +58,6 @@
 
 #include "events.h"
 
-/* WITH_INNOBASE_STORAGE_ENGINE */
-extern uint innobase_flush_log_at_trx_commit;
-extern ulong innobase_fast_shutdown;
-extern long innobase_mirrored_log_groups, innobase_log_files_in_group;
-extern longlong innobase_log_file_size;
-extern long innobase_log_buffer_size;
-extern longlong innobase_buffer_pool_size;
-extern long innobase_additional_mem_pool_size;
-extern long innobase_file_io_threads, innobase_lock_wait_timeout;
-extern long innobase_force_recovery;
-extern long innobase_open_files;
-extern char *innobase_data_home_dir, *innobase_data_file_path;
-extern char *innobase_log_group_home_dir, *innobase_log_arch_dir;
-extern char *innobase_unix_file_flush_method;
-/* The following variables have to be my_bool for SHOW VARIABLES to work */
-extern my_bool innobase_log_archive,
-               innobase_use_doublewrite,
-               innobase_use_checksums,
-               innobase_file_per_table,
-               innobase_locks_unsafe_for_binlog,
-               innobase_rollback_on_timeout;
-
-extern "C" {
-extern ulong srv_max_buf_pool_modified_pct;
-extern ulong srv_max_purge_lag;
-extern ulong srv_auto_extend_increment;
-extern ulong srv_n_spin_wait_rounds;
-extern ulong srv_n_free_tickets_to_enter;
-extern ulong srv_thread_sleep_delay;
-extern ulong srv_thread_concurrency;
-extern ulong srv_commit_concurrency;
-extern ulong srv_flush_log_at_trx_commit;
-}
 
 /* WITH_NDBCLUSTER_STORAGE_ENGINE */
 extern ulong ndb_cache_check_time;
@@ -100,9 +67,12 @@ extern ulong ndb_report_thresh_binlog_epoch_slip;
 extern ulong ndb_report_thresh_binlog_mem_usage;
 #endif
 
+extern CHARSET_INFO *character_set_filesystem;
 
 
+static DYNAMIC_ARRAY fixed_show_vars;
 static HASH system_variable_hash;
+
 const char *bool_type_names[]= { "OFF", "ON", NullS };
 TYPELIB bool_typelib=
 {
@@ -169,849 +139,554 @@ static void sys_default_slow_log_path(THD *thd, enum_var_type type);
   it in the constructor (see sys_var class for details).
 */
 
-sys_var *sys_var::first= NULL;
-uint sys_var::sys_vars= 0;
+static sys_var_chain vars = { NULL, NULL };
 
-sys_var_thd_ulong	sys_auto_increment_increment("auto_increment_increment",
+static sys_var_thd_ulong	sys_auto_increment_increment(&vars, "auto_increment_increment",
                                                      &SV::auto_increment_increment);
-sys_var_thd_ulong	sys_auto_increment_offset("auto_increment_offset",
+static sys_var_thd_ulong	sys_auto_increment_offset(&vars, "auto_increment_offset",
                                                   &SV::auto_increment_offset);
 
-sys_var_bool_ptr	sys_automatic_sp_privileges("automatic_sp_privileges",
+static sys_var_bool_ptr	sys_automatic_sp_privileges(&vars, "automatic_sp_privileges",
 					      &sp_automatic_privileges);
 
-sys_var_const_str       sys_basedir("basedir", mysql_home);
-sys_var_long_ptr	sys_binlog_cache_size("binlog_cache_size",
+static sys_var_const_str       sys_basedir(&vars, "basedir", mysql_home);
+static sys_var_long_ptr	sys_binlog_cache_size(&vars, "binlog_cache_size",
 					      &binlog_cache_size);
-sys_var_thd_binlog_format sys_binlog_format("binlog_format",
+static sys_var_thd_binlog_format sys_binlog_format(&vars, "binlog_format",
                                             &SV::binlog_format);
-sys_var_thd_ulong	sys_bulk_insert_buff_size("bulk_insert_buffer_size",
+static sys_var_thd_ulong	sys_bulk_insert_buff_size(&vars, "bulk_insert_buffer_size",
 						  &SV::bulk_insert_buff_size);
-sys_var_character_set_server	sys_character_set_server("character_set_server");
-sys_var_const_str       sys_charset_system("character_set_system",
+static sys_var_character_set_sv	sys_character_set_server(&vars, "character_set_server",
+                                        &SV::collation_server,
+                                        &default_charset_info);
+sys_var_const_str       sys_charset_system(&vars, "character_set_system",
                                            (char *)my_charset_utf8_general_ci.name);
-sys_var_character_set_database	sys_character_set_database("character_set_database");
-sys_var_character_set_client  sys_character_set_client("character_set_client");
-sys_var_character_set_connection  sys_character_set_connection("character_set_connection");
-sys_var_character_set_results sys_character_set_results("character_set_results");
-sys_var_character_set_filesystem  sys_character_set_filesystem("character_set_filesystem");
-sys_var_thd_ulong	sys_completion_type("completion_type",
+static sys_var_character_set_database	sys_character_set_database(&vars, "character_set_database");
+static sys_var_character_set_sv sys_character_set_client(&vars, "character_set_client",
+                                        &SV::character_set_client,
+                                        &default_charset_info);
+static sys_var_character_set_sv sys_character_set_connection(&vars, "character_set_connection",
+                                        &SV::collation_connection,
+                                        &default_charset_info);
+static sys_var_character_set_sv sys_character_set_results(&vars, "character_set_results",
+                                        &SV::character_set_results,
+                                        &default_charset_info, true);
+static sys_var_character_set_sv sys_character_set_filesystem(&vars, "character_set_filesystem",
+                                        &SV::character_set_filesystem,
+                                        &character_set_filesystem);
+static sys_var_thd_ulong	sys_completion_type(&vars, "completion_type",
 					 &SV::completion_type,
 					 check_completion_type,
 					 fix_completion_type);
-sys_var_collation_connection sys_collation_connection("collation_connection");
-sys_var_collation_database sys_collation_database("collation_database");
-sys_var_collation_server sys_collation_server("collation_server");
-sys_var_long_ptr	sys_concurrent_insert("concurrent_insert",
+static sys_var_collation_sv sys_collation_connection(&vars, "collation_connection",
+                                        &SV::collation_connection,
+                                        &default_charset_info);
+static sys_var_collation_sv sys_collation_database(&vars, "collation_database",
+                                        &SV::collation_database,
+                                        &default_charset_info);
+static sys_var_collation_sv sys_collation_server(&vars, "collation_server",
+                                        &SV::collation_server,
+                                        &default_charset_info);
+static sys_var_long_ptr	sys_concurrent_insert(&vars, "concurrent_insert",
                                               &myisam_concurrent_insert);
-sys_var_long_ptr	sys_connect_timeout("connect_timeout",
+static sys_var_long_ptr	sys_connect_timeout(&vars, "connect_timeout",
 					    &connect_timeout);
-sys_var_const_str       sys_datadir("datadir", mysql_real_data_home);
+static sys_var_const_str       sys_datadir(&vars, "datadir", mysql_real_data_home);
 #ifndef DBUG_OFF
-sys_var_thd_dbug        sys_dbug("debug");
+static sys_var_thd_dbug        sys_dbug(&vars, "debug");
 #endif
-sys_var_enum		sys_delay_key_write("delay_key_write",
+static sys_var_enum		sys_delay_key_write(&vars, "delay_key_write",
 					    &delay_key_write_options,
 					    &delay_key_write_typelib,
 					    fix_delay_key_write);
-sys_var_long_ptr	sys_delayed_insert_limit("delayed_insert_limit",
+static sys_var_long_ptr	sys_delayed_insert_limit(&vars, "delayed_insert_limit",
 						 &delayed_insert_limit);
-sys_var_long_ptr	sys_delayed_insert_timeout("delayed_insert_timeout",
+static sys_var_long_ptr	sys_delayed_insert_timeout(&vars, "delayed_insert_timeout",
 						   &delayed_insert_timeout);
-sys_var_long_ptr	sys_delayed_queue_size("delayed_queue_size",
+static sys_var_long_ptr	sys_delayed_queue_size(&vars, "delayed_queue_size",
 					       &delayed_queue_size);
 
-sys_var_event_scheduler sys_event_scheduler("event_scheduler");
-sys_var_long_ptr	sys_expire_logs_days("expire_logs_days",
+static sys_var_event_scheduler sys_event_scheduler(&vars, "event_scheduler");
+static sys_var_long_ptr	sys_expire_logs_days(&vars, "expire_logs_days",
 					     &expire_logs_days);
-sys_var_bool_ptr	sys_flush("flush", &myisam_flush);
-sys_var_long_ptr	sys_flush_time("flush_time", &flush_time);
-sys_var_str             sys_ft_boolean_syntax("ft_boolean_syntax",
+static sys_var_bool_ptr	sys_flush(&vars, "flush", &myisam_flush);
+static sys_var_long_ptr	sys_flush_time(&vars, "flush_time", &flush_time);
+static sys_var_str             sys_ft_boolean_syntax(&vars, "ft_boolean_syntax",
                                          sys_check_ftb_syntax,
                                          sys_update_ftb_syntax,
                                          sys_default_ftb_syntax,
                                          ft_boolean_syntax);
-sys_var_str             sys_init_connect("init_connect", 0,
+sys_var_str             sys_init_connect(&vars, "init_connect", 0,
                                          sys_update_init_connect,
                                          sys_default_init_connect,0);
-sys_var_str             sys_init_slave("init_slave", 0,
+sys_var_str             sys_init_slave(&vars, "init_slave", 0,
                                        sys_update_init_slave,
                                        sys_default_init_slave,0);
-sys_var_thd_ulong	sys_interactive_timeout("interactive_timeout",
+static sys_var_thd_ulong	sys_interactive_timeout(&vars, "interactive_timeout",
 						&SV::net_interactive_timeout);
-sys_var_thd_ulong	sys_join_buffer_size("join_buffer_size",
+static sys_var_thd_ulong	sys_join_buffer_size(&vars, "join_buffer_size",
 					     &SV::join_buff_size);
-sys_var_key_buffer_size	sys_key_buffer_size("key_buffer_size");
-sys_var_key_cache_long  sys_key_cache_block_size("key_cache_block_size",
+static sys_var_key_buffer_size	sys_key_buffer_size(&vars, "key_buffer_size");
+static sys_var_key_cache_long  sys_key_cache_block_size(&vars, "key_cache_block_size",
 						 offsetof(KEY_CACHE,
 							  param_block_size));
-sys_var_key_cache_long	sys_key_cache_division_limit("key_cache_division_limit",
+static sys_var_key_cache_long	sys_key_cache_division_limit(&vars, "key_cache_division_limit",
 						     offsetof(KEY_CACHE,
 							      param_division_limit));
-sys_var_key_cache_long  sys_key_cache_age_threshold("key_cache_age_threshold",
+static sys_var_key_cache_long  sys_key_cache_age_threshold(&vars, "key_cache_age_threshold",
 						     offsetof(KEY_CACHE,
 							      param_age_threshold));
-sys_var_bool_ptr	sys_local_infile("local_infile",
+static sys_var_bool_ptr	sys_local_infile(&vars, "local_infile",
 					 &opt_local_infile);
-sys_var_trust_routine_creators
-sys_trust_routine_creators("log_bin_trust_routine_creators",
+static sys_var_trust_routine_creators
+sys_trust_routine_creators(&vars, "log_bin_trust_routine_creators",
                            &trust_function_creators);
-sys_var_bool_ptr       
-sys_trust_function_creators("log_bin_trust_function_creators",
+static sys_var_bool_ptr       
+sys_trust_function_creators(&vars, "log_bin_trust_function_creators",
                             &trust_function_creators);
-sys_var_bool_ptr
-  sys_log_queries_not_using_indexes("log_queries_not_using_indexes",
+static sys_var_bool_ptr
+  sys_log_queries_not_using_indexes(&vars, "log_queries_not_using_indexes",
                                     &opt_log_queries_not_using_indexes);
-sys_var_thd_ulong	sys_log_warnings("log_warnings", &SV::log_warnings);
-sys_var_thd_ulong	sys_long_query_time("long_query_time",
+static sys_var_thd_ulong	sys_log_warnings(&vars, "log_warnings", &SV::log_warnings);
+static sys_var_thd_ulong	sys_long_query_time(&vars, "long_query_time",
 					     &SV::long_query_time);
-sys_var_thd_bool	sys_low_priority_updates("low_priority_updates",
+static sys_var_thd_bool	sys_low_priority_updates(&vars, "low_priority_updates",
 						 &SV::low_priority_updates,
 						 fix_low_priority_updates);
 #ifndef TO_BE_DELETED	/* Alias for the low_priority_updates */
-sys_var_thd_bool	sys_sql_low_priority_updates("sql_low_priority_updates",
+static sys_var_thd_bool	sys_sql_low_priority_updates(&vars, "sql_low_priority_updates",
 						     &SV::low_priority_updates,
 						     fix_low_priority_updates);
 #endif
-sys_var_thd_ulong	sys_max_allowed_packet("max_allowed_packet",
+static sys_var_thd_ulong	sys_max_allowed_packet(&vars, "max_allowed_packet",
 					       &SV::max_allowed_packet);
-sys_var_long_ptr	sys_max_binlog_cache_size("max_binlog_cache_size",
+static sys_var_long_ptr	sys_max_binlog_cache_size(&vars, "max_binlog_cache_size",
 						  &max_binlog_cache_size);
-sys_var_long_ptr	sys_max_binlog_size("max_binlog_size",
+static sys_var_long_ptr	sys_max_binlog_size(&vars, "max_binlog_size",
 					    &max_binlog_size,
                                             fix_max_binlog_size);
-sys_var_long_ptr	sys_max_connections("max_connections",
+static sys_var_long_ptr	sys_max_connections(&vars, "max_connections",
 					    &max_connections,
                                             fix_max_connections);
-sys_var_long_ptr	sys_max_connect_errors("max_connect_errors",
+static sys_var_long_ptr	sys_max_connect_errors(&vars, "max_connect_errors",
 					       &max_connect_errors);
-sys_var_thd_ulong       sys_max_insert_delayed_threads("max_insert_delayed_threads",
+static sys_var_thd_ulong       sys_max_insert_delayed_threads(&vars, "max_insert_delayed_threads",
 						       &SV::max_insert_delayed_threads,
                                                        check_max_delayed_threads,
                                                        fix_max_connections);
-sys_var_thd_ulong	sys_max_delayed_threads("max_delayed_threads",
+static sys_var_thd_ulong	sys_max_delayed_threads(&vars, "max_delayed_threads",
 						&SV::max_insert_delayed_threads,
                                                 check_max_delayed_threads,
                                                 fix_max_connections);
-sys_var_thd_ulong	sys_max_error_count("max_error_count",
+static sys_var_thd_ulong	sys_max_error_count(&vars, "max_error_count",
 					    &SV::max_error_count);
-sys_var_thd_ulonglong	sys_max_heap_table_size("max_heap_table_size",
+static sys_var_thd_ulonglong	sys_max_heap_table_size(&vars, "max_heap_table_size",
 						&SV::max_heap_table_size);
-sys_var_thd_ulong       sys_pseudo_thread_id("pseudo_thread_id",
+static sys_var_thd_ulong       sys_pseudo_thread_id(&vars, "pseudo_thread_id",
 					     &SV::pseudo_thread_id,
                                              check_pseudo_thread_id, 0);
-sys_var_thd_ha_rows	sys_max_join_size("max_join_size",
+static sys_var_thd_ha_rows	sys_max_join_size(&vars, "max_join_size",
 					  &SV::max_join_size,
 					  fix_max_join_size);
-sys_var_thd_ulong	sys_max_seeks_for_key("max_seeks_for_key",
+static sys_var_thd_ulong	sys_max_seeks_for_key(&vars, "max_seeks_for_key",
 					      &SV::max_seeks_for_key);
-sys_var_thd_ulong   sys_max_length_for_sort_data("max_length_for_sort_data",
+static sys_var_thd_ulong   sys_max_length_for_sort_data(&vars, "max_length_for_sort_data",
                                                  &SV::max_length_for_sort_data);
 #ifndef TO_BE_DELETED	/* Alias for max_join_size */
-sys_var_thd_ha_rows	sys_sql_max_join_size("sql_max_join_size",
+static sys_var_thd_ha_rows	sys_sql_max_join_size(&vars, "sql_max_join_size",
 					      &SV::max_join_size,
 					      fix_max_join_size);
 #endif
 static sys_var_long_ptr_global
-sys_max_prepared_stmt_count("max_prepared_stmt_count",
+sys_max_prepared_stmt_count(&vars, "max_prepared_stmt_count",
                             &max_prepared_stmt_count,
                             &LOCK_prepared_stmt_count);
-sys_var_long_ptr	sys_max_relay_log_size("max_relay_log_size",
+static sys_var_long_ptr	sys_max_relay_log_size(&vars, "max_relay_log_size",
                                                &max_relay_log_size,
                                                fix_max_relay_log_size);
-sys_var_thd_ulong	sys_max_sort_length("max_sort_length",
+static sys_var_thd_ulong	sys_max_sort_length(&vars, "max_sort_length",
 					    &SV::max_sort_length);
-sys_var_thd_ulong	sys_max_sp_recursion_depth("max_sp_recursion_depth",
+static sys_var_thd_ulong	sys_max_sp_recursion_depth(&vars, "max_sp_recursion_depth",
                                                    &SV::max_sp_recursion_depth);
-sys_var_max_user_conn   sys_max_user_connections("max_user_connections");
-sys_var_thd_ulong	sys_max_tmp_tables("max_tmp_tables",
+static sys_var_max_user_conn   sys_max_user_connections(&vars, "max_user_connections");
+static sys_var_thd_ulong	sys_max_tmp_tables(&vars, "max_tmp_tables",
 					   &SV::max_tmp_tables);
-sys_var_long_ptr	sys_max_write_lock_count("max_write_lock_count",
+static sys_var_long_ptr	sys_max_write_lock_count(&vars, "max_write_lock_count",
 						 &max_write_lock_count);
-sys_var_thd_ulong       sys_multi_range_count("multi_range_count",
+static sys_var_thd_ulong       sys_multi_range_count(&vars, "multi_range_count",
                                               &SV::multi_range_count);
-sys_var_long_ptr	sys_myisam_data_pointer_size("myisam_data_pointer_size",
+static sys_var_long_ptr	sys_myisam_data_pointer_size(&vars, "myisam_data_pointer_size",
                                                     &myisam_data_pointer_size);
-sys_var_thd_ulonglong	sys_myisam_max_sort_file_size("myisam_max_sort_file_size", &SV::myisam_max_sort_file_size, fix_myisam_max_sort_file_size, 1);
-sys_var_thd_ulong       sys_myisam_repair_threads("myisam_repair_threads", &SV::myisam_repair_threads);
-sys_var_thd_ulong	sys_myisam_sort_buffer_size("myisam_sort_buffer_size", &SV::myisam_sort_buff_size);
-sys_var_bool_ptr	sys_myisam_use_mmap("myisam_use_mmap", 
+static sys_var_thd_ulonglong	sys_myisam_max_sort_file_size(&vars, "myisam_max_sort_file_size", &SV::myisam_max_sort_file_size, fix_myisam_max_sort_file_size, 1);
+static sys_var_thd_ulong       sys_myisam_repair_threads(&vars, "myisam_repair_threads", &SV::myisam_repair_threads);
+static sys_var_thd_ulong	sys_myisam_sort_buffer_size(&vars, "myisam_sort_buffer_size", &SV::myisam_sort_buff_size);
+static sys_var_bool_ptr	sys_myisam_use_mmap(&vars, "myisam_use_mmap", 
                                             &opt_myisam_use_mmap);
 
-sys_var_thd_enum        sys_myisam_stats_method("myisam_stats_method",
+static sys_var_thd_enum        sys_myisam_stats_method(&vars, "myisam_stats_method",
                                                 &SV::myisam_stats_method,
                                                 &myisam_stats_method_typelib,
                                                 NULL);
 
-sys_var_thd_ulong	sys_net_buffer_length("net_buffer_length",
+static sys_var_thd_ulong	sys_net_buffer_length(&vars, "net_buffer_length",
 					      &SV::net_buffer_length);
-sys_var_thd_ulong	sys_net_read_timeout("net_read_timeout",
+static sys_var_thd_ulong	sys_net_read_timeout(&vars, "net_read_timeout",
 					     &SV::net_read_timeout,
 					     0, fix_net_read_timeout);
-sys_var_thd_ulong	sys_net_write_timeout("net_write_timeout",
+static sys_var_thd_ulong	sys_net_write_timeout(&vars, "net_write_timeout",
 					      &SV::net_write_timeout,
 					      0, fix_net_write_timeout);
-sys_var_thd_ulong	sys_net_retry_count("net_retry_count",
+static sys_var_thd_ulong	sys_net_retry_count(&vars, "net_retry_count",
 					    &SV::net_retry_count,
 					    0, fix_net_retry_count);
-sys_var_thd_bool	sys_new_mode("new", &SV::new_mode);
-sys_var_thd_bool	sys_old_alter_table("old_alter_table",
+static sys_var_thd_bool	sys_new_mode(&vars, "new", &SV::new_mode);
+sys_var_thd_bool	sys_old_alter_table(&vars, "old_alter_table",
 					    &SV::old_alter_table);
-sys_var_thd_bool	sys_old_passwords("old_passwords", &SV::old_passwords);
-sys_var_thd_ulong       sys_optimizer_prune_level("optimizer_prune_level",
+sys_var_thd_bool	sys_old_passwords(&vars, "old_passwords", &SV::old_passwords);
+static sys_var_thd_ulong       sys_optimizer_prune_level(&vars, "optimizer_prune_level",
                                                   &SV::optimizer_prune_level);
-sys_var_thd_ulong       sys_optimizer_search_depth("optimizer_search_depth",
+static sys_var_thd_ulong       sys_optimizer_search_depth(&vars, "optimizer_search_depth",
                                                    &SV::optimizer_search_depth);
-sys_var_thd_ulong       sys_preload_buff_size("preload_buffer_size",
+static sys_var_thd_ulong       sys_preload_buff_size(&vars, "preload_buffer_size",
                                               &SV::preload_buff_size);
-sys_var_thd_ulong	sys_read_buff_size("read_buffer_size",
+static sys_var_thd_ulong	sys_read_buff_size(&vars, "read_buffer_size",
 					   &SV::read_buff_size);
-sys_var_opt_readonly    sys_readonly("read_only", &opt_readonly);
-sys_var_thd_ulong	sys_read_rnd_buff_size("read_rnd_buffer_size",
+static sys_var_opt_readonly	sys_readonly(&vars, "read_only", &opt_readonly);
+static sys_var_thd_ulong	sys_read_rnd_buff_size(&vars, "read_rnd_buffer_size",
 					       &SV::read_rnd_buff_size);
-sys_var_thd_ulong	sys_div_precincrement("div_precision_increment",
+static sys_var_thd_ulong	sys_div_precincrement(&vars, "div_precision_increment",
                                               &SV::div_precincrement);
-#ifdef HAVE_REPLICATION
-sys_var_bool_ptr	sys_relay_log_purge("relay_log_purge",
-                                            &relay_log_purge);
-#endif
-sys_var_long_ptr	sys_rpl_recovery_rank("rpl_recovery_rank",
+static sys_var_long_ptr	sys_rpl_recovery_rank(&vars, "rpl_recovery_rank",
 					      &rpl_recovery_rank);
-sys_var_long_ptr	sys_query_cache_size("query_cache_size",
+static sys_var_long_ptr	sys_query_cache_size(&vars, "query_cache_size",
 					     &query_cache_size,
 					     fix_query_cache_size);
 
-sys_var_thd_ulong	sys_range_alloc_block_size("range_alloc_block_size",
+static sys_var_thd_ulong	sys_range_alloc_block_size(&vars, "range_alloc_block_size",
 						   &SV::range_alloc_block_size);
-sys_var_thd_ulong	sys_query_alloc_block_size("query_alloc_block_size",
+static sys_var_thd_ulong	sys_query_alloc_block_size(&vars, "query_alloc_block_size",
 						   &SV::query_alloc_block_size,
 						   0, fix_thd_mem_root);
-sys_var_thd_ulong	sys_query_prealloc_size("query_prealloc_size",
+static sys_var_thd_ulong	sys_query_prealloc_size(&vars, "query_prealloc_size",
 						&SV::query_prealloc_size,
 						0, fix_thd_mem_root);
-sys_var_readonly        sys_tmpdir("tmpdir", OPT_GLOBAL, SHOW_CHAR, get_tmpdir);
-sys_var_thd_ulong	sys_trans_alloc_block_size("transaction_alloc_block_size",
+static sys_var_readonly        sys_tmpdir(&vars, "tmpdir", OPT_GLOBAL, SHOW_CHAR, get_tmpdir);
+static sys_var_thd_ulong	sys_trans_alloc_block_size(&vars, "transaction_alloc_block_size",
 						   &SV::trans_alloc_block_size,
 						   0, fix_trans_mem_root);
-sys_var_thd_ulong	sys_trans_prealloc_size("transaction_prealloc_size",
+static sys_var_thd_ulong	sys_trans_prealloc_size(&vars, "transaction_prealloc_size",
 						&SV::trans_prealloc_size,
 						0, fix_trans_mem_root);
-sys_var_thd_enum        sys_thread_handling("thread_handling",
+sys_var_thd_enum        sys_thread_handling(&vars, "thread_handling",
                                             &SV::thread_handling,
                                             &thread_handling_typelib,
                                             NULL);
 
 #ifdef HAVE_QUERY_CACHE
-sys_var_long_ptr	sys_query_cache_limit("query_cache_limit",
+static sys_var_long_ptr	sys_query_cache_limit(&vars, "query_cache_limit",
 					      &query_cache.query_cache_limit);
-sys_var_long_ptr        sys_query_cache_min_res_unit("query_cache_min_res_unit",
+static sys_var_long_ptr        sys_query_cache_min_res_unit(&vars, "query_cache_min_res_unit",
 						     &query_cache_min_res_unit,
 						     fix_query_cache_min_res_unit);
-sys_var_thd_enum	sys_query_cache_type("query_cache_type",
+static sys_var_thd_enum	sys_query_cache_type(&vars, "query_cache_type",
 					     &SV::query_cache_type,
 					     &query_cache_type_typelib);
-sys_var_thd_bool
-sys_query_cache_wlock_invalidate("query_cache_wlock_invalidate",
+static sys_var_thd_bool
+sys_query_cache_wlock_invalidate(&vars, "query_cache_wlock_invalidate",
 				 &SV::query_cache_wlock_invalidate);
 #endif /* HAVE_QUERY_CACHE */
-sys_var_bool_ptr	sys_secure_auth("secure_auth", &opt_secure_auth);
-sys_var_long_ptr	sys_server_id("server_id", &server_id, fix_server_id);
-sys_var_bool_ptr	sys_slave_compressed_protocol("slave_compressed_protocol",
+static sys_var_bool_ptr	sys_secure_auth(&vars, "secure_auth", &opt_secure_auth);
+static sys_var_long_ptr	sys_server_id(&vars, "server_id", &server_id, fix_server_id);
+static sys_var_bool_ptr	sys_slave_compressed_protocol(&vars, "slave_compressed_protocol",
 						      &opt_slave_compressed_protocol);
-#ifdef HAVE_REPLICATION
-sys_var_long_ptr	sys_slave_net_timeout("slave_net_timeout",
-					      &slave_net_timeout);
-sys_var_long_ptr	sys_slave_trans_retries("slave_transaction_retries",
-                                                &slave_trans_retries);
-#endif
-sys_var_long_ptr	sys_slow_launch_time("slow_launch_time",
+static sys_var_long_ptr	sys_slow_launch_time(&vars, "slow_launch_time",
 					     &slow_launch_time);
-sys_var_thd_ulong	sys_sort_buffer("sort_buffer_size",
+static sys_var_thd_ulong	sys_sort_buffer(&vars, "sort_buffer_size",
 					&SV::sortbuff_size);
-sys_var_thd_sql_mode    sys_sql_mode("sql_mode",
+static sys_var_thd_sql_mode    sys_sql_mode(&vars, "sql_mode",
                                      &SV::sql_mode);
 #ifdef HAVE_OPENSSL
 extern char *opt_ssl_ca, *opt_ssl_capath, *opt_ssl_cert, *opt_ssl_cipher,
             *opt_ssl_key;
-sys_var_const_str_ptr	sys_ssl_ca("ssl_ca", &opt_ssl_ca);
-sys_var_const_str_ptr	sys_ssl_capath("ssl_capath", &opt_ssl_capath);
-sys_var_const_str_ptr	sys_ssl_cert("ssl_cert", &opt_ssl_cert);
-sys_var_const_str_ptr	sys_ssl_cipher("ssl_cipher", &opt_ssl_cipher);
-sys_var_const_str_ptr	sys_ssl_key("ssl_key", &opt_ssl_key);
+static sys_var_const_str_ptr	sys_ssl_ca(&vars, "ssl_ca", &opt_ssl_ca);
+static sys_var_const_str_ptr	sys_ssl_capath(&vars, "ssl_capath", &opt_ssl_capath);
+static sys_var_const_str_ptr	sys_ssl_cert(&vars, "ssl_cert", &opt_ssl_cert);
+static sys_var_const_str_ptr	sys_ssl_cipher(&vars, "ssl_cipher", &opt_ssl_cipher);
+static sys_var_const_str_ptr	sys_ssl_key(&vars, "ssl_key", &opt_ssl_key);
 #else
-sys_var_const_str	sys_ssl_ca("ssl_ca", NULL);
-sys_var_const_str	sys_ssl_capath("ssl_capath", NULL);
-sys_var_const_str	sys_ssl_cert("ssl_cert", NULL);
-sys_var_const_str	sys_ssl_cipher("ssl_cipher", NULL);
-sys_var_const_str	sys_ssl_key("ssl_key", NULL);
+static sys_var_const_str	sys_ssl_ca(&vars, "ssl_ca", NULL);
+static sys_var_const_str	sys_ssl_capath(&vars, "ssl_capath", NULL);
+static sys_var_const_str	sys_ssl_cert(&vars, "ssl_cert", NULL);
+static sys_var_const_str	sys_ssl_cipher(&vars, "ssl_cipher", NULL);
+static sys_var_const_str	sys_ssl_key(&vars, "ssl_key", NULL);
 #endif
-sys_var_thd_enum
-sys_updatable_views_with_limit("updatable_views_with_limit",
+static sys_var_thd_enum
+sys_updatable_views_with_limit(&vars, "updatable_views_with_limit",
                                &SV::updatable_views_with_limit,
                                &updatable_views_with_limit_typelib);
 
-sys_var_thd_table_type  sys_table_type("table_type",
-				       &SV::table_type);
-sys_var_thd_storage_engine sys_storage_engine("storage_engine",
-				       &SV::table_type);
-#ifdef HAVE_REPLICATION
-sys_var_sync_binlog_period sys_sync_binlog_period("sync_binlog", &sync_binlog_period);
-#endif
-sys_var_bool_ptr	sys_sync_frm("sync_frm", &opt_sync_frm);
-sys_var_const_str	sys_system_time_zone("system_time_zone",
+static sys_var_thd_table_type  sys_table_type(&vars, "table_type",
+				       &SV::table_plugin);
+static sys_var_thd_storage_engine sys_storage_engine(&vars, "storage_engine",
+				       &SV::table_plugin);
+static sys_var_bool_ptr	sys_sync_frm(&vars, "sync_frm", &opt_sync_frm);
+static sys_var_const_str	sys_system_time_zone(&vars, "system_time_zone",
                                              system_time_zone);
-sys_var_long_ptr	sys_table_def_size("table_definition_cache",
+static sys_var_long_ptr	sys_table_def_size(&vars, "table_definition_cache",
                                            &table_def_size);
-sys_var_long_ptr	sys_table_cache_size("table_open_cache",
+static sys_var_long_ptr	sys_table_cache_size(&vars, "table_open_cache",
 					     &table_cache_size);
-sys_var_long_ptr	sys_table_lock_wait_timeout("table_lock_wait_timeout",
+static sys_var_long_ptr	sys_table_lock_wait_timeout(&vars, "table_lock_wait_timeout",
                                                     &table_lock_wait_timeout);
-sys_var_long_ptr	sys_thread_cache_size("thread_cache_size",
+static sys_var_long_ptr	sys_thread_cache_size(&vars, "thread_cache_size",
 					      &thread_cache_size);
 #if HAVE_POOL_OF_THREADS == 1
-sys_var_long_ptr	sys_thread_pool_size("thread_pool_size",
+sys_var_long_ptr	sys_thread_pool_size(&vars, "thread_pool_size",
 					      &thread_pool_size);
 #endif
-sys_var_thd_enum	sys_tx_isolation("tx_isolation",
+static sys_var_thd_enum	sys_tx_isolation(&vars, "tx_isolation",
 					 &SV::tx_isolation,
 					 &tx_isolation_typelib,
 					 fix_tx_isolation,
 					 check_tx_isolation);
-sys_var_thd_ulonglong	sys_tmp_table_size("tmp_table_size",
+static sys_var_thd_ulonglong	sys_tmp_table_size(&vars, "tmp_table_size",
 					   &SV::tmp_table_size);
-sys_var_bool_ptr  sys_timed_mutexes("timed_mutexes",
+static sys_var_bool_ptr  sys_timed_mutexes(&vars, "timed_mutexes",
                                     &timed_mutexes);
-sys_var_const_str	sys_version("version", server_version);
-sys_var_const_str	sys_version_comment("version_comment",
+static sys_var_const_str	sys_version(&vars, "version", server_version);
+static sys_var_const_str	sys_version_comment(&vars, "version_comment",
                                             MYSQL_COMPILATION_COMMENT);
-sys_var_const_str	sys_version_compile_machine("version_compile_machine",
+static sys_var_const_str	sys_version_compile_machine(&vars, "version_compile_machine",
                                                     MACHINE_TYPE);
-sys_var_const_str	sys_version_compile_os("version_compile_os",
+static sys_var_const_str	sys_version_compile_os(&vars, "version_compile_os",
                                                SYSTEM_TYPE);
-sys_var_thd_ulong	sys_net_wait_timeout("wait_timeout",
+static sys_var_thd_ulong	sys_net_wait_timeout(&vars, "wait_timeout",
 					     &SV::net_wait_timeout);
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-sys_var_long_ptr	sys_innodb_fast_shutdown("innodb_fast_shutdown",
-						 &innobase_fast_shutdown);
-sys_var_long_ptr        sys_innodb_max_dirty_pages_pct("innodb_max_dirty_pages_pct",
-                                                        &srv_max_buf_pool_modified_pct);
-sys_var_long_ptr	sys_innodb_max_purge_lag("innodb_max_purge_lag",
-							&srv_max_purge_lag);
-sys_var_thd_bool	sys_innodb_table_locks("innodb_table_locks",
-                                               &SV::innodb_table_locks);
-sys_var_thd_bool	sys_innodb_support_xa("innodb_support_xa",
-                                               &SV::innodb_support_xa);
-sys_var_long_ptr	sys_innodb_autoextend_increment("innodb_autoextend_increment",
-							&srv_auto_extend_increment);
-sys_var_long_ptr	sys_innodb_sync_spin_loops("innodb_sync_spin_loops",
-                                             &srv_n_spin_wait_rounds);
-sys_var_long_ptr  sys_innodb_concurrency_tickets("innodb_concurrency_tickets",
-                                             &srv_n_free_tickets_to_enter);
-sys_var_long_ptr  sys_innodb_thread_sleep_delay("innodb_thread_sleep_delay",
-                                                &srv_thread_sleep_delay);
-sys_var_long_ptr  sys_innodb_thread_concurrency("innodb_thread_concurrency",
-                                                &srv_thread_concurrency);
-sys_var_long_ptr  sys_innodb_commit_concurrency("innodb_commit_concurrency",
-                                                &srv_commit_concurrency);
-sys_var_long_ptr  sys_innodb_flush_log_at_trx_commit(
-                                        "innodb_flush_log_at_trx_commit",
-                                        &srv_flush_log_at_trx_commit);
-#endif
+
 /* Condition pushdown to storage engine */
-sys_var_thd_bool
-sys_engine_condition_pushdown("engine_condition_pushdown",
+static sys_var_thd_bool
+sys_engine_condition_pushdown(&vars, "engine_condition_pushdown",
 			      &SV::engine_condition_pushdown);
 
 /* ndb thread specific variable settings */
-sys_var_thd_ulong
-sys_ndb_autoincrement_prefetch_sz("ndb_autoincrement_prefetch_sz",
+static sys_var_thd_ulong
+sys_ndb_autoincrement_prefetch_sz(&vars, "ndb_autoincrement_prefetch_sz",
 				  &SV::ndb_autoincrement_prefetch_sz);
-sys_var_thd_bool
-sys_ndb_force_send("ndb_force_send", &SV::ndb_force_send);
+static sys_var_thd_bool
+sys_ndb_force_send(&vars, "ndb_force_send", &SV::ndb_force_send);
 #ifdef HAVE_NDB_BINLOG
-sys_var_long_ptr
-sys_ndb_report_thresh_binlog_epoch_slip("ndb_report_thresh_binlog_epoch_slip",
+static sys_var_long_ptr
+sys_ndb_report_thresh_binlog_epoch_slip(&vars, "ndb_report_thresh_binlog_epoch_slip",
                                         &ndb_report_thresh_binlog_epoch_slip);
-sys_var_long_ptr
-sys_ndb_report_thresh_binlog_mem_usage("ndb_report_thresh_binlog_mem_usage",
+static sys_var_long_ptr
+sys_ndb_report_thresh_binlog_mem_usage(&vars, "ndb_report_thresh_binlog_mem_usage",
                                        &ndb_report_thresh_binlog_mem_usage);
 #endif
-sys_var_thd_bool
-sys_ndb_use_exact_count("ndb_use_exact_count", &SV::ndb_use_exact_count);
-sys_var_thd_bool
-sys_ndb_use_transactions("ndb_use_transactions", &SV::ndb_use_transactions);
-sys_var_long_ptr
-sys_ndb_cache_check_time("ndb_cache_check_time", &ndb_cache_check_time);
-sys_var_thd_bool
-sys_ndb_index_stat_enable("ndb_index_stat_enable",
+static sys_var_thd_bool
+sys_ndb_use_exact_count(&vars, "ndb_use_exact_count", &SV::ndb_use_exact_count);
+static sys_var_thd_bool
+sys_ndb_use_transactions(&vars, "ndb_use_transactions", &SV::ndb_use_transactions);
+static sys_var_long_ptr
+sys_ndb_cache_check_time(&vars, "ndb_cache_check_time", &ndb_cache_check_time);
+static sys_var_thd_bool
+sys_ndb_index_stat_enable(&vars, "ndb_index_stat_enable",
                           &SV::ndb_index_stat_enable);
-sys_var_thd_ulong
-sys_ndb_index_stat_cache_entries("ndb_index_stat_cache_entries",
+static sys_var_thd_ulong
+sys_ndb_index_stat_cache_entries(&vars, "ndb_index_stat_cache_entries",
                                  &SV::ndb_index_stat_cache_entries);
-sys_var_thd_ulong
-sys_ndb_index_stat_update_freq("ndb_index_stat_update_freq",
+static sys_var_thd_ulong
+sys_ndb_index_stat_update_freq(&vars, "ndb_index_stat_update_freq",
                                &SV::ndb_index_stat_update_freq);
-sys_var_long_ptr
-sys_ndb_extra_logging("ndb_extra_logging", &ndb_extra_logging);
-sys_var_thd_bool
-sys_ndb_use_copying_alter_table("ndb_use_copying_alter_table", &SV::ndb_use_copying_alter_table);
+static sys_var_long_ptr
+sys_ndb_extra_logging(&vars, "ndb_extra_logging", &ndb_extra_logging);
+static sys_var_thd_bool
+sys_ndb_use_copying_alter_table(&vars, "ndb_use_copying_alter_table", &SV::ndb_use_copying_alter_table);
 
 /* Time/date/datetime formats */
 
-sys_var_thd_date_time_format sys_time_format("time_format",
+static sys_var_thd_date_time_format sys_time_format(&vars, "time_format",
 					     &SV::time_format,
 					     MYSQL_TIMESTAMP_TIME);
-sys_var_thd_date_time_format sys_date_format("date_format",
+static sys_var_thd_date_time_format sys_date_format(&vars, "date_format",
 					     &SV::date_format,
 					     MYSQL_TIMESTAMP_DATE);
-sys_var_thd_date_time_format sys_datetime_format("datetime_format",
+static sys_var_thd_date_time_format sys_datetime_format(&vars, "datetime_format",
 						 &SV::datetime_format,
 						 MYSQL_TIMESTAMP_DATETIME);
 
 /* Variables that are bits in THD */
 
-sys_var_thd_bit sys_autocommit("autocommit", 0,
+sys_var_thd_bit sys_autocommit(&vars, "autocommit", 0,
                                set_option_autocommit,
                                OPTION_NOT_AUTOCOMMIT,
                                1);
-static sys_var_thd_bit	sys_big_tables("big_tables", 0,
+static sys_var_thd_bit	sys_big_tables(&vars, "big_tables", 0,
 				       set_option_bit,
 				       OPTION_BIG_TABLES);
 #ifndef TO_BE_DELETED	/* Alias for big_tables */
-static sys_var_thd_bit	sys_sql_big_tables("sql_big_tables", 0,
+static sys_var_thd_bit	sys_sql_big_tables(&vars, "sql_big_tables", 0,
 					   set_option_bit,
 					   OPTION_BIG_TABLES);
 #endif
-static sys_var_thd_bit	sys_big_selects("sql_big_selects", 0,
+static sys_var_thd_bit	sys_big_selects(&vars, "sql_big_selects", 0,
 					set_option_bit,
 					OPTION_BIG_SELECTS);
-static sys_var_thd_bit	sys_log_off("sql_log_off",
+static sys_var_thd_bit	sys_log_off(&vars, "sql_log_off",
 				    check_log_update,
 				    set_option_bit,
 				    OPTION_LOG_OFF);
-static sys_var_thd_bit	sys_log_update("sql_log_update",
+static sys_var_thd_bit	sys_log_update(&vars, "sql_log_update",
                                        check_log_update,
 				       set_log_update,
 				       OPTION_BIN_LOG);
-static sys_var_thd_bit	sys_log_binlog("sql_log_bin",
+static sys_var_thd_bit	sys_log_binlog(&vars, "sql_log_bin",
                                        check_log_update,
 				       set_option_bit,
 				       OPTION_BIN_LOG);
-static sys_var_thd_bit	sys_sql_warnings("sql_warnings", 0,
+static sys_var_thd_bit	sys_sql_warnings(&vars, "sql_warnings", 0,
 					 set_option_bit,
 					 OPTION_WARNINGS);
-static sys_var_thd_bit	sys_sql_notes("sql_notes", 0,
+static sys_var_thd_bit	sys_sql_notes(&vars, "sql_notes", 0,
 					 set_option_bit,
 					 OPTION_SQL_NOTES);
-static sys_var_thd_bit	sys_auto_is_null("sql_auto_is_null", 0,
+static sys_var_thd_bit	sys_auto_is_null(&vars, "sql_auto_is_null", 0,
 					 set_option_bit,
 					 OPTION_AUTO_IS_NULL);
-static sys_var_thd_bit	sys_safe_updates("sql_safe_updates", 0,
+static sys_var_thd_bit	sys_safe_updates(&vars, "sql_safe_updates", 0,
 					 set_option_bit,
 					 OPTION_SAFE_UPDATES);
-static sys_var_thd_bit	sys_buffer_results("sql_buffer_result", 0,
+static sys_var_thd_bit	sys_buffer_results(&vars, "sql_buffer_result", 0,
 					   set_option_bit,
 					   OPTION_BUFFER_RESULT);
-static sys_var_thd_bit	sys_quote_show_create("sql_quote_show_create", 0,
+static sys_var_thd_bit	sys_quote_show_create(&vars, "sql_quote_show_create", 0,
 					      set_option_bit,
 					      OPTION_QUOTE_SHOW_CREATE);
-static sys_var_thd_bit	sys_foreign_key_checks("foreign_key_checks", 0,
+static sys_var_thd_bit	sys_foreign_key_checks(&vars, "foreign_key_checks", 0,
 					       set_option_bit,
 					       OPTION_NO_FOREIGN_KEY_CHECKS,
 					       1);
-static sys_var_thd_bit	sys_unique_checks("unique_checks", 0,
+static sys_var_thd_bit	sys_unique_checks(&vars, "unique_checks", 0,
 					  set_option_bit,
 					  OPTION_RELAXED_UNIQUE_CHECKS,
 					  1);
 
 /* Local state variables */
 
-static sys_var_thd_ha_rows	sys_select_limit("sql_select_limit",
+static sys_var_thd_ha_rows	sys_select_limit(&vars, "sql_select_limit",
 						 &SV::select_limit);
-static sys_var_timestamp	sys_timestamp("timestamp");
-static sys_var_last_insert_id	sys_last_insert_id("last_insert_id");
-static sys_var_last_insert_id	sys_identity("identity");
+static sys_var_timestamp	sys_timestamp(&vars, "timestamp");
+static sys_var_last_insert_id	sys_last_insert_id(&vars, "last_insert_id");
+static sys_var_last_insert_id	sys_identity(&vars, "identity");
 
-static sys_var_thd_lc_time_names       sys_lc_time_names("lc_time_names");
+static sys_var_thd_lc_time_names       sys_lc_time_names(&vars, "lc_time_names");
 
-static sys_var_insert_id	sys_insert_id("insert_id");
-static sys_var_readonly		sys_error_count("error_count",
+static sys_var_insert_id	sys_insert_id(&vars, "insert_id");
+static sys_var_readonly		sys_error_count(&vars, "error_count",
 						OPT_SESSION,
 						SHOW_LONG,
 						get_error_count);
-static sys_var_readonly		sys_warning_count("warning_count",
+static sys_var_readonly		sys_warning_count(&vars, "warning_count",
 						  OPT_SESSION,
 						  SHOW_LONG,
 						  get_warning_count);
 
 /* alias for last_insert_id() to be compatible with Sybase */
-#ifdef HAVE_REPLICATION
-static sys_var_slave_skip_counter sys_slave_skip_counter("sql_slave_skip_counter");
-#endif
-static sys_var_rand_seed1	sys_rand_seed1("rand_seed1");
-static sys_var_rand_seed2	sys_rand_seed2("rand_seed2");
+static sys_var_rand_seed1	sys_rand_seed1(&vars, "rand_seed1");
+static sys_var_rand_seed2	sys_rand_seed2(&vars, "rand_seed2");
 
-static sys_var_thd_ulong        sys_default_week_format("default_week_format",
+static sys_var_thd_ulong        sys_default_week_format(&vars, "default_week_format",
 					                &SV::default_week_format);
 
-sys_var_thd_ulong               sys_group_concat_max_len("group_concat_max_len",
+sys_var_thd_ulong               sys_group_concat_max_len(&vars, "group_concat_max_len",
                                                          &SV::group_concat_max_len);
 
-sys_var_thd_time_zone            sys_time_zone("time_zone");
+sys_var_thd_time_zone            sys_time_zone(&vars, "time_zone");
 
 /* Read only variables */
 
-sys_var_have_variable sys_have_compress("have_compress", &have_compress);
-sys_var_have_variable sys_have_crypt("have_crypt", &have_crypt);
-sys_var_have_variable sys_have_csv_db("have_csv", &have_csv_db);
-sys_var_have_variable sys_have_dlopen("have_dynamic_loading", &have_dlopen);
-sys_var_have_variable sys_have_geometry("have_geometry", &have_geometry);
-sys_var_have_variable sys_have_innodb("have_innodb", &have_innodb);
-sys_var_have_variable sys_have_ndbcluster("have_ndbcluster", &have_ndbcluster);
-sys_var_have_variable sys_have_openssl("have_openssl", &have_openssl);
-sys_var_have_variable sys_have_partition_db("have_partitioning",
-                                            &have_partition_db);
-sys_var_have_variable sys_have_query_cache("have_query_cache",
+static sys_var_have_variable sys_have_compress(&vars, "have_compress", &have_compress);
+static sys_var_have_variable sys_have_crypt(&vars, "have_crypt", &have_crypt);
+static sys_var_have_plugin sys_have_csv(&vars, "have_csv", C_STRING_WITH_LEN("csv"), MYSQL_STORAGE_ENGINE_PLUGIN);
+static sys_var_have_variable sys_have_dlopen(&vars, "have_dynamic_loading", &have_dlopen);
+static sys_var_have_variable sys_have_geometry(&vars, "have_geometry", &have_geometry);
+static sys_var_have_plugin sys_have_innodb(&vars, "have_innodb", C_STRING_WITH_LEN("innodb"), MYSQL_STORAGE_ENGINE_PLUGIN);
+static sys_var_have_plugin sys_have_ndbcluster(&vars, "have_ndbcluster", C_STRING_WITH_LEN("ndbcluster"), MYSQL_STORAGE_ENGINE_PLUGIN);
+static sys_var_have_variable sys_have_openssl(&vars, "have_openssl", &have_openssl);
+static sys_var_have_plugin sys_have_partition_db(&vars, "have_partitioning", C_STRING_WITH_LEN("partition"), MYSQL_STORAGE_ENGINE_PLUGIN);
+static sys_var_have_variable sys_have_query_cache(&vars, "have_query_cache",
                                            &have_query_cache);
-sys_var_have_variable sys_have_rtree_keys("have_rtree_keys", &have_rtree_keys);
-sys_var_have_variable sys_have_symlink("have_symlink", &have_symlink);
+static sys_var_have_variable sys_have_rtree_keys(&vars, "have_rtree_keys", &have_rtree_keys);
+static sys_var_have_variable sys_have_symlink(&vars, "have_symlink", &have_symlink);
 /* Global read-only variable describing server license */
-sys_var_const_str		sys_license("license", STRINGIFY_ARG(LICENSE));
+static sys_var_const_str	sys_license(&vars, "license", STRINGIFY_ARG(LICENSE));
 
 /* Global variables which enable|disable logging */
-sys_var_log_state sys_var_general_log("general_log", &opt_log,
+static sys_var_log_state sys_var_general_log(&vars, "general_log", &opt_log,
                                       QUERY_LOG_GENERAL);
-sys_var_log_state sys_var_slow_query_log("slow_query_log", &opt_slow_log,
+static sys_var_log_state sys_var_slow_query_log(&vars, "slow_query_log", &opt_slow_log,
                                          QUERY_LOG_SLOW);
-sys_var_str sys_var_general_log_path("general_log_file", sys_check_log_path,
+sys_var_str sys_var_general_log_path(&vars, "general_log_file", sys_check_log_path,
 				     sys_update_general_log_path,
 				     sys_default_general_log_path,
 				     opt_logname);
-sys_var_str sys_var_slow_log_path("slow_query_log_file", sys_check_log_path,
+sys_var_str sys_var_slow_log_path(&vars, "slow_query_log_file", sys_check_log_path,
 				  sys_update_slow_log_path, 
 				  sys_default_slow_log_path,
 				  opt_slow_logname);
-sys_var_log_output sys_var_log_output_state("log_output", &log_output_options,
+static sys_var_log_output sys_var_log_output_state(&vars, "log_output", &log_output_options,
 					    &log_output_typelib, 0);
 
-#ifdef HAVE_REPLICATION
-static int show_slave_skip_errors(THD *thd, SHOW_VAR *var, char *buff)
-{
-  var->type=SHOW_CHAR;
-  var->value= buff;
-  if (!use_slave_mask || bitmap_is_clear_all(&slave_error_mask))
-  {
-    var->value= const_cast<char *>("OFF");
-  }
-  else if (bitmap_is_set_all(&slave_error_mask))
-  {
-    var->value= const_cast<char *>("ALL");
-  }
-  else
-  {
-    /* 10 is enough assuming errors are max 4 digits */
-    int i;
-    var->value= buff;
-    for (i= 1;
-         i < MAX_SLAVE_ERROR &&
-         (buff - var->value) < SHOW_VAR_FUNC_BUFF_SIZE;
-         i++)
-    {
-      if (bitmap_is_set(&slave_error_mask, i))
-      {
-        buff= int10_to_str(i, buff, 10);
-        *buff++= ',';
-      }
-    }
-    if (var->value != buff)
-      buff--;				// Remove last ','
-    if (i < MAX_SLAVE_ERROR)
-      buff= strmov(buff, "...");  // Couldn't show all errors
-    *buff=0;
-  }
-  return 0;
-}
-#endif /* HAVE_REPLICATION */
 
 /*
-  Variables shown by SHOW VARIABLES in alphabetical order
+  Additional variables (not derived from sys_var class, not accessible as
+  @@varname in SELECT or SET). Sorted in alphabetical order to facilitate
+  maintenance - SHOW VARIABLES will sort its output.
+  TODO: remove this list completely
 */
 
-SHOW_VAR init_vars[]= {
-  {"auto_increment_increment", (char*) &sys_auto_increment_increment, SHOW_SYS},
-  {"auto_increment_offset",   (char*) &sys_auto_increment_offset, SHOW_SYS},
-  {sys_automatic_sp_privileges.name,(char*) &sys_automatic_sp_privileges,       SHOW_SYS},
+#define FIXED_VARS_SIZE (sizeof(fixed_vars) / sizeof(SHOW_VAR))
+static SHOW_VAR fixed_vars[]= {
   {"back_log",                (char*) &back_log,                    SHOW_LONG},
-  {sys_basedir.name,          (char*) &sys_basedir,                 SHOW_SYS},
-  {sys_binlog_cache_size.name,(char*) &sys_binlog_cache_size,	    SHOW_SYS},
-  {sys_binlog_format.name,    (char*) &sys_binlog_format,	    SHOW_SYS},
-  {sys_bulk_insert_buff_size.name,(char*) &sys_bulk_insert_buff_size,SHOW_SYS},
-  {sys_character_set_client.name,(char*) &sys_character_set_client, SHOW_SYS},
-  {sys_character_set_connection.name,(char*) &sys_character_set_connection,SHOW_SYS},
-  {sys_character_set_database.name, (char*) &sys_character_set_database,SHOW_SYS},
-  {sys_character_set_filesystem.name,(char*) &sys_character_set_filesystem, SHOW_SYS},
-  {sys_character_set_results.name,(char*) &sys_character_set_results, SHOW_SYS},
-  {sys_character_set_server.name, (char*) &sys_character_set_server,SHOW_SYS},
-  {sys_charset_system.name,   (char*) &sys_charset_system,          SHOW_SYS},
   {"character_sets_dir",      mysql_charsets_dir,                   SHOW_CHAR},
-  {sys_collation_connection.name,(char*) &sys_collation_connection, SHOW_SYS},
-  {sys_collation_database.name,(char*) &sys_collation_database,     SHOW_SYS},
-  {sys_collation_server.name,(char*) &sys_collation_server,         SHOW_SYS},
-  {sys_completion_type.name,  (char*) &sys_completion_type,	    SHOW_SYS},
-  {sys_concurrent_insert.name,(char*) &sys_concurrent_insert,       SHOW_SYS},
-  {sys_connect_timeout.name,  (char*) &sys_connect_timeout,         SHOW_SYS},
-  {sys_datadir.name,          (char*) &sys_datadir,                 SHOW_SYS},
-  {sys_date_format.name,      (char*) &sys_date_format,		    SHOW_SYS},
-  {sys_datetime_format.name,  (char*) &sys_datetime_format,	    SHOW_SYS},
-#ifndef DBUG_OFF
-  {sys_dbug.name,             (char*) &sys_dbug,                    SHOW_SYS},
-#endif
-  {sys_default_week_format.name, (char*) &sys_default_week_format,  SHOW_SYS},
-  {sys_delay_key_write.name,  (char*) &sys_delay_key_write,         SHOW_SYS},
-  {sys_delayed_insert_limit.name, (char*) &sys_delayed_insert_limit,SHOW_SYS},
-  {sys_delayed_insert_timeout.name, (char*) &sys_delayed_insert_timeout, SHOW_SYS},
-  {sys_delayed_queue_size.name,(char*) &sys_delayed_queue_size,     SHOW_SYS},
-  {sys_div_precincrement.name,(char*) &sys_div_precincrement,SHOW_SYS},
-  {sys_engine_condition_pushdown.name,
-   (char*) &sys_engine_condition_pushdown,                          SHOW_SYS},
-  {sys_event_scheduler.name,  (char*) &sys_event_scheduler,         SHOW_SYS},
-  {sys_expire_logs_days.name, (char*) &sys_expire_logs_days,        SHOW_SYS},
-  {sys_flush.name,             (char*) &sys_flush,                  SHOW_SYS},
-  {sys_flush_time.name,        (char*) &sys_flush_time,             SHOW_SYS},
-  {sys_ft_boolean_syntax.name,(char*) &ft_boolean_syntax,	    SHOW_CHAR},
   {"ft_max_word_len",         (char*) &ft_max_word_len,             SHOW_LONG},
   {"ft_min_word_len",         (char*) &ft_min_word_len,             SHOW_LONG},
   {"ft_query_expansion_limit",(char*) &ft_query_expansion_limit,    SHOW_LONG},
   {"ft_stopword_file",        (char*) &ft_stopword_file,            SHOW_CHAR_PTR},
-  {sys_var_general_log.name, (char*) &opt_log,                      SHOW_MY_BOOL},
-  {sys_var_general_log_path.name, (char*) &sys_var_general_log_path,  SHOW_SYS},
-  {sys_group_concat_max_len.name, (char*) &sys_group_concat_max_len,  SHOW_SYS},
-  {sys_have_compress.name,    (char*) &have_compress,               SHOW_HAVE},
-  {sys_have_crypt.name,       (char*) &have_crypt,                  SHOW_HAVE},
-  {sys_have_csv_db.name,      (char*) &have_csv_db,                 SHOW_HAVE},
-  {sys_have_dlopen.name,      (char*) &have_dlopen,                 SHOW_HAVE},
-  {sys_have_geometry.name,    (char*) &have_geometry,               SHOW_HAVE},
-  {sys_have_innodb.name,      (char*) &have_innodb,                 SHOW_HAVE},
-  {sys_have_ndbcluster.name,  (char*) &have_ndbcluster,             SHOW_HAVE},
-  {sys_have_openssl.name,     (char*) &have_openssl,                SHOW_HAVE},
-  {sys_have_partition_db.name,(char*) &have_partition_db,           SHOW_HAVE},
-  {sys_have_query_cache.name, (char*) &have_query_cache,            SHOW_HAVE},
-  {sys_have_rtree_keys.name,  (char*) &have_rtree_keys,             SHOW_HAVE},
-  {sys_have_symlink.name,     (char*) &have_symlink,                SHOW_HAVE},
-  {"init_connect",            (char*) &sys_init_connect,            SHOW_SYS},
   {"init_file",               (char*) &opt_init_file,               SHOW_CHAR_PTR},
-  {"init_slave",              (char*) &sys_init_slave,              SHOW_SYS},
-#ifdef WITH_INNOBASE_STORAGE_ENGINE
-  {"innodb_additional_mem_pool_size", (char*) &innobase_additional_mem_pool_size, SHOW_LONG },
-  {sys_innodb_autoextend_increment.name, (char*) &sys_innodb_autoextend_increment, SHOW_SYS},
-  {"innodb_buffer_pool_size", (char*) &innobase_buffer_pool_size, SHOW_LONGLONG },
-  {"innodb_checksums", (char*) &innobase_use_checksums, SHOW_MY_BOOL},
-  {sys_innodb_commit_concurrency.name, (char*) &sys_innodb_commit_concurrency, SHOW_SYS},
-  {sys_innodb_concurrency_tickets.name, (char*) &sys_innodb_concurrency_tickets, SHOW_SYS},
-  {"innodb_data_file_path", (char*) &innobase_data_file_path,	    SHOW_CHAR_PTR},
-  {"innodb_data_home_dir",  (char*) &innobase_data_home_dir,	    SHOW_CHAR_PTR},
-  {"innodb_doublewrite", (char*) &innobase_use_doublewrite, SHOW_MY_BOOL},
-  {sys_innodb_fast_shutdown.name,(char*) &sys_innodb_fast_shutdown, SHOW_SYS},
-  {"innodb_file_io_threads", (char*) &innobase_file_io_threads, SHOW_LONG },
-  {"innodb_file_per_table", (char*) &innobase_file_per_table, SHOW_MY_BOOL},
-  {"innodb_flush_method",    (char*) &innobase_unix_file_flush_method, SHOW_CHAR_PTR},
-  {"innodb_force_recovery", (char*) &innobase_force_recovery, SHOW_LONG },
-  {"innodb_lock_wait_timeout", (char*) &innobase_lock_wait_timeout, SHOW_LONG },
-  {"innodb_locks_unsafe_for_binlog", (char*) &innobase_locks_unsafe_for_binlog, SHOW_MY_BOOL},
-  {"innodb_log_arch_dir",   (char*) &innobase_log_arch_dir, 	    SHOW_CHAR_PTR},
-  {"innodb_log_archive",    (char*) &innobase_log_archive, 	    SHOW_MY_BOOL},
-  {"innodb_log_buffer_size", (char*) &innobase_log_buffer_size, SHOW_LONG },
-  {"innodb_log_file_size", (char*) &innobase_log_file_size, SHOW_LONGLONG},
-  {"innodb_log_files_in_group", (char*) &innobase_log_files_in_group,	SHOW_LONG},
-  {"innodb_log_group_home_dir", (char*) &innobase_log_group_home_dir, SHOW_CHAR_PTR},
-  {sys_innodb_max_dirty_pages_pct.name, (char*) &sys_innodb_max_dirty_pages_pct, SHOW_SYS},
-  {sys_innodb_max_purge_lag.name, (char*) &sys_innodb_max_purge_lag, SHOW_SYS},
-  {"innodb_mirrored_log_groups", (char*) &innobase_mirrored_log_groups, SHOW_LONG},
-  {"innodb_open_files", (char*) &innobase_open_files, SHOW_LONG },
-  {"innodb_rollback_on_timeout", (char*) &innobase_rollback_on_timeout, SHOW_MY_BOOL},
-  {sys_innodb_support_xa.name, (char*) &sys_innodb_support_xa, SHOW_SYS},
-  {sys_innodb_sync_spin_loops.name, (char*) &sys_innodb_sync_spin_loops, SHOW_SYS},
-  {sys_innodb_table_locks.name, (char*) &sys_innodb_table_locks, SHOW_SYS},
-  {sys_innodb_thread_concurrency.name, (char*) &sys_innodb_thread_concurrency, SHOW_SYS},
-  {sys_innodb_thread_sleep_delay.name, (char*) &sys_innodb_thread_sleep_delay, SHOW_SYS},
-  {sys_innodb_flush_log_at_trx_commit.name, (char*) &sys_innodb_flush_log_at_trx_commit, SHOW_SYS},
-#endif
-  {sys_interactive_timeout.name,(char*) &sys_interactive_timeout,   SHOW_SYS},
-  {sys_join_buffer_size.name,   (char*) &sys_join_buffer_size,	    SHOW_SYS},
-  {sys_key_buffer_size.name,	(char*) &sys_key_buffer_size,	    SHOW_SYS},
-  {sys_key_cache_age_threshold.name,   (char*) &sys_key_cache_age_threshold,
-                                                                    SHOW_SYS},
-  {sys_key_cache_block_size.name,   (char*) &sys_key_cache_block_size,
-                                                                    SHOW_SYS},
-  {sys_key_cache_division_limit.name,   (char*) &sys_key_cache_division_limit,
-                                                                    SHOW_SYS},
   {"language",                language,                             SHOW_CHAR},
   {"large_files_support",     (char*) &opt_large_files,             SHOW_BOOL},
   {"large_page_size",         (char*) &opt_large_page_size,         SHOW_INT},
   {"large_pages",             (char*) &opt_large_pages,             SHOW_MY_BOOL},
-  {sys_lc_time_names.name,    (char*) &sys_lc_time_names,           SHOW_SYS},
-  {sys_license.name,	      (char*) &sys_license,                 SHOW_SYS},
-  {sys_local_infile.name,     (char*) &sys_local_infile,	    SHOW_SYS},
 #ifdef HAVE_MLOCKALL
-  {"locked_in_memory",	      (char*) &locked_in_memory,	    SHOW_BOOL},
+  {"locked_in_memory",	      (char*) &locked_in_memory,	    SHOW_MY_BOOL},
 #endif
-  {"log",                     (char*) &opt_log,                     SHOW_BOOL},
+  {"log",                     (char*) &opt_log,                     SHOW_MY_BOOL},
   {"log_bin",                 (char*) &opt_bin_log,                 SHOW_BOOL},
-  {sys_trust_function_creators.name,(char*) &sys_trust_function_creators, SHOW_SYS},
   {"log_error",               (char*) log_error_file,               SHOW_CHAR},
-  {sys_var_log_output_state.name, (char*) &sys_var_log_output_state, SHOW_SYS},
-  {sys_log_queries_not_using_indexes.name,
-    (char*) &sys_log_queries_not_using_indexes, SHOW_SYS},
-#ifdef HAVE_REPLICATION
-  {"log_slave_updates",       (char*) &opt_log_slave_updates,       SHOW_MY_BOOL},
-#endif
-  {"log_slow_queries",        (char*) &opt_slow_log,                SHOW_BOOL},
-  {sys_log_warnings.name,     (char*) &sys_log_warnings,	    SHOW_SYS},
-  {sys_long_query_time.name,  (char*) &sys_long_query_time, 	    SHOW_SYS},
-  {sys_low_priority_updates.name, (char*) &sys_low_priority_updates, SHOW_SYS},
+  {"log_slow_queries",        (char*) &opt_slow_log,                SHOW_MY_BOOL},
   {"lower_case_file_system",  (char*) &lower_case_file_system,      SHOW_MY_BOOL},
   {"lower_case_table_names",  (char*) &lower_case_table_names,      SHOW_INT},
-  {sys_max_allowed_packet.name,(char*) &sys_max_allowed_packet,	    SHOW_SYS},
-  {sys_max_binlog_cache_size.name,(char*) &sys_max_binlog_cache_size, SHOW_SYS},
-  {sys_max_binlog_size.name,    (char*) &sys_max_binlog_size,	    SHOW_SYS},
-  {sys_max_connect_errors.name, (char*) &sys_max_connect_errors,    SHOW_SYS},
-  {sys_max_connections.name,    (char*) &sys_max_connections,	    SHOW_SYS},
-  {sys_max_delayed_threads.name,(char*) &sys_max_delayed_threads,   SHOW_SYS},
-  {sys_max_error_count.name,	(char*) &sys_max_error_count,	    SHOW_SYS},
-  {sys_max_heap_table_size.name,(char*) &sys_max_heap_table_size,   SHOW_SYS},
-  {sys_max_insert_delayed_threads.name,
-   (char*) &sys_max_insert_delayed_threads,   SHOW_SYS},
-  {sys_max_join_size.name,	(char*) &sys_max_join_size,	    SHOW_SYS},
-  {sys_max_length_for_sort_data.name, (char*) &sys_max_length_for_sort_data,
-   SHOW_SYS},
-  {sys_max_prepared_stmt_count.name, (char*) &sys_max_prepared_stmt_count,
-    SHOW_SYS},
-  {sys_max_relay_log_size.name, (char*) &sys_max_relay_log_size,    SHOW_SYS},
-  {sys_max_seeks_for_key.name,  (char*) &sys_max_seeks_for_key,	    SHOW_SYS},
-  {sys_max_sort_length.name,	(char*) &sys_max_sort_length,	    SHOW_SYS},
-  {sys_max_sp_recursion_depth.name,
-    (char*) &sys_max_sp_recursion_depth, SHOW_SYS},
-  {sys_max_tmp_tables.name,	(char*) &sys_max_tmp_tables,	    SHOW_SYS},
-  {sys_max_user_connections.name,(char*) &sys_max_user_connections, SHOW_SYS},
-  {sys_max_write_lock_count.name, (char*) &sys_max_write_lock_count,SHOW_SYS},
-  {sys_multi_range_count.name,  (char*) &sys_multi_range_count,     SHOW_SYS},
-  {sys_myisam_data_pointer_size.name, (char*) &sys_myisam_data_pointer_size, SHOW_SYS},
-  {sys_myisam_max_sort_file_size.name, (char*) &sys_myisam_max_sort_file_size,
-   SHOW_SYS},
   {"myisam_recover_options",  (char*) &myisam_recover_options_str,  SHOW_CHAR_PTR},
-  {sys_myisam_repair_threads.name, (char*) &sys_myisam_repair_threads,
-   SHOW_SYS},
-  {sys_myisam_sort_buffer_size.name, (char*) &sys_myisam_sort_buffer_size, SHOW_SYS},
-  
-  {sys_myisam_stats_method.name, (char*) &sys_myisam_stats_method, SHOW_SYS},
-  {sys_myisam_use_mmap.name, (char*) &sys_myisam_use_mmap, SHOW_SYS},
-  
 #ifdef __NT__
   {"named_pipe",	      (char*) &opt_enable_named_pipe,       SHOW_MY_BOOL},
 #endif
-  {sys_ndb_autoincrement_prefetch_sz.name,
-   (char*) &sys_ndb_autoincrement_prefetch_sz,                      SHOW_SYS},
-  {sys_ndb_cache_check_time.name,(char*) &sys_ndb_cache_check_time, SHOW_SYS},
-  {sys_ndb_extra_logging.name,(char*) &sys_ndb_extra_logging,       SHOW_SYS},
-  {sys_ndb_force_send.name,   (char*) &sys_ndb_force_send,          SHOW_SYS},
-  {sys_ndb_index_stat_cache_entries.name, (char*) &sys_ndb_index_stat_cache_entries, SHOW_SYS},
-  {sys_ndb_index_stat_enable.name, (char*) &sys_ndb_index_stat_enable, SHOW_SYS},
-  {sys_ndb_index_stat_update_freq.name, (char*) &sys_ndb_index_stat_update_freq, SHOW_SYS},
-#ifdef HAVE_NDB_BINLOG
-  {sys_ndb_report_thresh_binlog_epoch_slip.name,
-   (char*) &sys_ndb_report_thresh_binlog_epoch_slip,                SHOW_SYS},
-  {sys_ndb_report_thresh_binlog_mem_usage.name,
-   (char*) &sys_ndb_report_thresh_binlog_mem_usage,                 SHOW_SYS},
-#endif
-  {sys_ndb_use_copying_alter_table.name,
-   (char*) &sys_ndb_use_copying_alter_table,                        SHOW_SYS},
-  {sys_ndb_use_exact_count.name,(char*) &sys_ndb_use_exact_count,   SHOW_SYS},
-  {sys_ndb_use_transactions.name,(char*) &sys_ndb_use_transactions, SHOW_SYS},
-  {sys_net_buffer_length.name,(char*) &sys_net_buffer_length,       SHOW_SYS},
-  {sys_net_read_timeout.name, (char*) &sys_net_read_timeout,        SHOW_SYS},
-  {sys_net_retry_count.name,  (char*) &sys_net_retry_count,	    SHOW_SYS},
-  {sys_net_write_timeout.name,(char*) &sys_net_write_timeout,       SHOW_SYS},
-  {sys_new_mode.name,         (char*) &sys_new_mode,                SHOW_SYS},
-  {sys_old_alter_table.name,  (char*) &sys_old_alter_table,         SHOW_SYS},
-  {sys_old_passwords.name,    (char*) &sys_old_passwords,           SHOW_SYS},
   {"open_files_limit",	      (char*) &open_files_limit,	    SHOW_LONG},
-  {sys_optimizer_prune_level.name, (char*) &sys_optimizer_prune_level,
-   SHOW_SYS},
-  {sys_optimizer_search_depth.name,(char*) &sys_optimizer_search_depth,
-   SHOW_SYS},
   {"pid_file",                (char*) pidfile_name,                 SHOW_CHAR},
   {"plugin_dir",              (char*) opt_plugin_dir,               SHOW_CHAR},
-  {"port",                    (char*) &mysqld_port,                  SHOW_INT},
-  {sys_preload_buff_size.name, (char*) &sys_preload_buff_size,      SHOW_SYS},
+  {"port",                    (char*) &mysqld_port,                 SHOW_INT},
   {"protocol_version",        (char*) &protocol_version,            SHOW_INT},
-  {sys_query_alloc_block_size.name, (char*) &sys_query_alloc_block_size,
-   SHOW_SYS},
-#ifdef HAVE_QUERY_CACHE
-  {sys_query_cache_limit.name,(char*) &sys_query_cache_limit,	    SHOW_SYS},
-  {sys_query_cache_min_res_unit.name, (char*) &sys_query_cache_min_res_unit,
-   SHOW_SYS},
-  {sys_query_cache_size.name, (char*) &sys_query_cache_size,	    SHOW_SYS},
-  {sys_query_cache_type.name, (char*) &sys_query_cache_type,        SHOW_SYS},
-  {sys_query_cache_wlock_invalidate.name,
-   (char *) &sys_query_cache_wlock_invalidate, SHOW_SYS},
-#endif /* HAVE_QUERY_CACHE */
-  {sys_query_prealloc_size.name, (char*) &sys_query_prealloc_size,  SHOW_SYS},
-  {sys_range_alloc_block_size.name, (char*) &sys_range_alloc_block_size,
-   SHOW_SYS},
-  {sys_read_buff_size.name,   (char*) &sys_read_buff_size,	    SHOW_SYS},
-  {sys_readonly.name,         (char*) &sys_readonly,                SHOW_SYS},
-  {sys_read_rnd_buff_size.name,(char*) &sys_read_rnd_buff_size,	    SHOW_SYS},
-#ifdef HAVE_REPLICATION
-  {sys_relay_log_purge.name,  (char*) &sys_relay_log_purge,         SHOW_SYS},
-  {"relay_log_space_limit",  (char*) &relay_log_space_limit,        SHOW_LONGLONG},
-#endif
-  {sys_rpl_recovery_rank.name,(char*) &sys_rpl_recovery_rank,       SHOW_SYS},
-  {"secure_auth",             (char*) &sys_secure_auth,             SHOW_SYS},
 #ifdef HAVE_SMEM
   {"shared_memory",           (char*) &opt_enable_shared_memory,    SHOW_MY_BOOL},
   {"shared_memory_base_name", (char*) &shared_memory_base_name,     SHOW_CHAR_PTR},
 #endif
-  {sys_server_id.name,	      (char*) &sys_server_id,		    SHOW_SYS},
   {"skip_external_locking",   (char*) &my_disable_locking,          SHOW_MY_BOOL},
   {"skip_networking",         (char*) &opt_disable_networking,      SHOW_BOOL},
   {"skip_show_database",      (char*) &opt_skip_show_db,            SHOW_BOOL},
-#ifdef HAVE_REPLICATION
-  {sys_slave_compressed_protocol.name,
-    (char*) &sys_slave_compressed_protocol,           SHOW_SYS},
-  {"slave_load_tmpdir",       (char*) &slave_load_tmpdir,           SHOW_CHAR_PTR},
-  {sys_slave_net_timeout.name,(char*) &sys_slave_net_timeout,	    SHOW_SYS},
-  {"slave_skip_errors",       (char*) &show_slave_skip_errors,      SHOW_FUNC},
-  {sys_slave_trans_retries.name,(char*) &sys_slave_trans_retries,   SHOW_SYS},
-#endif
-  {sys_slow_launch_time.name, (char*) &sys_slow_launch_time,        SHOW_SYS},
-  {sys_var_slow_query_log.name, (char*) &opt_slow_log,              SHOW_MY_BOOL},
-  {sys_var_slow_log_path.name, (char*) &sys_var_slow_log_path,      SHOW_SYS},
 #ifdef HAVE_SYS_UN_H
-  {"socket",                  (char*) &mysqld_unix_port,             SHOW_CHAR_PTR},
-#endif
-  {sys_sort_buffer.name,      (char*) &sys_sort_buffer,             SHOW_SYS},
-  {sys_big_selects.name,      (char*) &sys_big_selects,             SHOW_SYS},
-  {sys_sql_mode.name,         (char*) &sys_sql_mode,                SHOW_SYS},
-  {"sql_notes",               (char*) &sys_sql_notes,               SHOW_SYS},
-  {"sql_warnings",            (char*) &sys_sql_warnings,            SHOW_SYS},
-  {sys_ssl_ca.name,           (char*) &sys_ssl_ca,                  SHOW_SYS},
-  {sys_ssl_capath.name,       (char*) &sys_ssl_capath,              SHOW_SYS},
-  {sys_ssl_cert.name,         (char*) &sys_ssl_cert,                SHOW_SYS},
-  {sys_ssl_cipher.name,       (char*) &sys_ssl_cipher,              SHOW_SYS},
-  {sys_ssl_key.name,          (char*) &sys_ssl_key,                 SHOW_SYS},
-  {sys_storage_engine.name,   (char*) &sys_storage_engine,          SHOW_SYS},
-#ifdef HAVE_REPLICATION
-  {sys_sync_binlog_period.name,(char*) &sys_sync_binlog_period,     SHOW_SYS},
-#endif
-  {sys_sync_frm.name,         (char*) &sys_sync_frm,               SHOW_SYS},
-#ifdef HAVE_TZNAME
-  {"system_time_zone",        system_time_zone,                     SHOW_CHAR},
+  {"socket",                  (char*) &mysqld_unix_port,            SHOW_CHAR_PTR},
 #endif
   {"table_definition_cache",  (char*) &table_def_size,              SHOW_LONG},
   {"table_lock_wait_timeout", (char*) &table_lock_wait_timeout,     SHOW_LONG },
-  {"table_open_cache",        (char*) &table_cache_size,            SHOW_LONG},
-  {sys_table_type.name,	      (char*) &sys_table_type,	            SHOW_SYS},
-  {sys_thread_cache_size.name,(char*) &sys_thread_cache_size,       SHOW_SYS},
 #ifdef HAVE_THR_SETCONCURRENCY
   {"thread_concurrency",      (char*) &concurrency,                 SHOW_LONG},
 #endif
@@ -1020,24 +695,6 @@ SHOW_VAR init_vars[]= {
   {sys_thread_pool_size.name, (char*) &sys_thread_pool_size,        SHOW_SYS},
 #endif
   {"thread_stack",            (char*) &thread_stack,                SHOW_LONG},
-  {sys_time_format.name,      (char*) &sys_time_format,		    SHOW_SYS},
-  {"time_zone",               (char*) &sys_time_zone,               SHOW_SYS},
-  {sys_timed_mutexes.name,    (char*) &sys_timed_mutexes,       SHOW_SYS},
-  {sys_tmp_table_size.name,   (char*) &sys_tmp_table_size,	    SHOW_SYS},
-  {sys_tmpdir.name,           (char*) &sys_tmpdir,	            SHOW_SYS},
-  {sys_trans_alloc_block_size.name, (char*) &sys_trans_alloc_block_size,
-   SHOW_SYS},
-  {sys_trans_prealloc_size.name, (char*) &sys_trans_prealloc_size,  SHOW_SYS},
-  {sys_tx_isolation.name,     (char*) &sys_tx_isolation,	    SHOW_SYS},
-  {sys_updatable_views_with_limit.name,
-                              (char*) &sys_updatable_views_with_limit,SHOW_SYS},
-  {sys_version.name,          (char*) &sys_version,                 SHOW_SYS},
-  {sys_version_comment.name,  (char*) &sys_version_comment,         SHOW_SYS},
-  {sys_version_compile_machine.name, (char*) &sys_version_compile_machine,
-   SHOW_SYS},
-  {sys_version_compile_os.name,	(char*) &sys_version_compile_os,    SHOW_SYS},
-  {sys_net_wait_timeout.name, (char*) &sys_net_wait_timeout,	    SHOW_SYS},
-  {NullS, NullS, SHOW_LONG}
 };
 
 
@@ -1332,7 +989,8 @@ bool sys_var_thd_binlog_format::is_readonly() const
   /*
     Cluster does not support changing the binlog format on the fly yet.
   */
-  if (opt_bin_log && (have_ndbcluster == SHOW_OPTION_YES))
+  LEX_STRING ndb_name= {(char*)STRING_WITH_LEN("ndbcluster")};
+  if (opt_bin_log && plugin_is_ready(&ndb_name, MYSQL_STORAGE_ENGINE_PLUGIN))
   {
     my_error(ER_NDB_CANT_SWITCH_BINLOG_FORMAT, MYF(0));
     return 1;
@@ -1423,9 +1081,9 @@ static void fix_server_id(THD *thd, enum_var_type type)
 
 
 sys_var_long_ptr::
-sys_var_long_ptr(const char *name_arg, ulong *value_ptr_arg,
+sys_var_long_ptr(sys_var_chain *chain, const char *name_arg, ulong *value_ptr_arg,
                  sys_after_update_func after_update_arg)
-  :sys_var_long_ptr_global(name_arg, value_ptr_arg,
+  :sys_var_long_ptr_global(chain, name_arg, value_ptr_arg,
                            &LOCK_global_system_variables, after_update_arg)
 {}
 
@@ -1809,7 +1467,13 @@ Item *sys_var::item(THD *thd, enum_var_type var_type, LEX_STRING *base)
     return new Item_int((longlong) value);
   }
   case SHOW_MY_BOOL:
-    return new Item_int((int32) *(my_bool*) value_ptr(thd, var_type, base),1);
+  {
+    int32 value;
+    pthread_mutex_lock(&LOCK_global_system_variables);
+    value= *(my_bool*) value_ptr(thd, var_type, base);
+    pthread_mutex_unlock(&LOCK_global_system_variables);
+    return new Item_int(value,1);
+  }
   case SHOW_CHAR:
   {
     Item *tmp;
@@ -2118,122 +1782,25 @@ byte *sys_var_character_set::value_ptr(THD *thd, enum_var_type type,
 }
 
 
-CHARSET_INFO ** sys_var_character_set_connection::ci_ptr(THD *thd,
-							 enum_var_type type)
-{
-  if (type == OPT_GLOBAL)
-    return &global_system_variables.collation_connection;
-  else
-    return &thd->variables.collation_connection;
-}
-
-
-void sys_var_character_set_connection::set_default(THD *thd,
-						   enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.collation_connection= default_charset_info;
- else
- {
-   thd->variables.collation_connection= global_system_variables.collation_connection;
-   thd->update_charset();
- }
-}
-
-
-CHARSET_INFO ** sys_var_character_set_client::ci_ptr(THD *thd,
-						     enum_var_type type)
+void sys_var_character_set_sv::set_default(THD *thd, enum_var_type type)
 {
   if (type == OPT_GLOBAL)
-    return &global_system_variables.character_set_client;
+    global_system_variables.*offset= *global_default;
   else
-    return &thd->variables.character_set_client;
-}
-
-
-void sys_var_character_set_client::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.character_set_client= default_charset_info;
- else
- {
-   thd->variables.character_set_client= (global_system_variables.
-					 character_set_client);
-   thd->update_charset();
- }
-}
-
-
-CHARSET_INFO **
-sys_var_character_set_filesystem::ci_ptr(THD *thd, enum_var_type type)
-{
-  if (type == OPT_GLOBAL)
-    return &global_system_variables.character_set_filesystem;
-  else
-    return &thd->variables.character_set_filesystem;
-}
-
-
-extern CHARSET_INFO *character_set_filesystem;
-
-void
-sys_var_character_set_filesystem::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.character_set_filesystem= character_set_filesystem;
- else
- {
-   thd->variables.character_set_filesystem= (global_system_variables.
-					     character_set_filesystem);
-   thd->update_charset();
- }
-}
-
-
-CHARSET_INFO **
-sys_var_character_set_results::ci_ptr(THD *thd, enum_var_type type)
-{
-  if (type == OPT_GLOBAL)
-    return &global_system_variables.character_set_results;
-  else
-    return &thd->variables.character_set_results;
-}
-
-
-void sys_var_character_set_results::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.character_set_results= default_charset_info;
- else
- {
-   thd->variables.character_set_results= (global_system_variables.
-					  character_set_results);
-   thd->update_charset();
- }
+  {
+    thd->variables.*offset= global_system_variables.*offset;
+    thd->update_charset();
+  }
 }
-
-
-CHARSET_INFO **
-sys_var_character_set_server::ci_ptr(THD *thd, enum_var_type type)
+CHARSET_INFO **sys_var_character_set_sv::ci_ptr(THD *thd, enum_var_type type)
 {
   if (type == OPT_GLOBAL)
-    return &global_system_variables.collation_server;
+    return &(global_system_variables.*offset);
   else
-    return &thd->variables.collation_server;
+    return &(thd->variables.*offset);
 }
 
 
-void sys_var_character_set_server::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.collation_server= default_charset_info;
- else
- {
-   thd->variables.collation_server= global_system_variables.collation_server;
-   thd->update_charset();
- }
-}
-
 CHARSET_INFO ** sys_var_character_set_database::ci_ptr(THD *thd,
 						       enum_var_type type)
 {
@@ -2256,113 +1823,39 @@ void sys_var_character_set_database::set_default(THD *thd, enum_var_type type)
 }
 
 
-bool sys_var_collation_connection::update(THD *thd, set_var *var)
-{
-  if (var->type == OPT_GLOBAL)
-    global_system_variables.collation_connection= var->save_result.charset;
-  else
-  {
-    thd->variables.collation_connection= var->save_result.charset;
-    thd->update_charset();
-  }
-  return 0;
-}
-
-
-byte *sys_var_collation_connection::value_ptr(THD *thd, enum_var_type type,
-					      LEX_STRING *base)
-{
-  CHARSET_INFO *cs= ((type == OPT_GLOBAL) ?
-		  global_system_variables.collation_connection :
-		  thd->variables.collation_connection);
-  return cs ? (byte*) cs->name : (byte*) "NULL";
-}
-
-
-void sys_var_collation_connection::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.collation_connection= default_charset_info;
- else
- {
-   thd->variables.collation_connection= (global_system_variables.
-					 collation_connection);
-   thd->update_charset();
- }
-}
-
-bool sys_var_collation_database::update(THD *thd, set_var *var)
+bool sys_var_collation_sv::update(THD *thd, set_var *var)
 {
   if (var->type == OPT_GLOBAL)
-    global_system_variables.collation_database= var->save_result.charset;
+    global_system_variables.*offset= var->save_result.charset;
   else
   {
-    thd->variables.collation_database= var->save_result.charset;
+    thd->variables.*offset= var->save_result.charset;
     thd->update_charset();
   }
   return 0;
 }
 
 
-byte *sys_var_collation_database::value_ptr(THD *thd, enum_var_type type,
-					      LEX_STRING *base)
-{
-  CHARSET_INFO *cs= ((type == OPT_GLOBAL) ?
-		  global_system_variables.collation_database :
-		  thd->variables.collation_database);
-  return cs ? (byte*) cs->name : (byte*) "NULL";
-}
-
-
-void sys_var_collation_database::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.collation_database= default_charset_info;
- else
- {
-   thd->variables.collation_database= (global_system_variables.
-					 collation_database);
-   thd->update_charset();
- }
-}
-
-
-bool sys_var_collation_server::update(THD *thd, set_var *var)
+void sys_var_collation_sv::set_default(THD *thd, enum_var_type type)
 {
-  if (var->type == OPT_GLOBAL)
-    global_system_variables.collation_server= var->save_result.charset;
+  if (type == OPT_GLOBAL)
+    global_system_variables.*offset= *global_default;
   else
   {
-    thd->variables.collation_server= var->save_result.charset;
+    thd->variables.*offset= global_system_variables.*offset;
     thd->update_charset();
   }
-  return 0;
 }
 
 
-byte *sys_var_collation_server::value_ptr(THD *thd, enum_var_type type,
-					      LEX_STRING *base)
+byte *sys_var_collation_sv::value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
 {
   CHARSET_INFO *cs= ((type == OPT_GLOBAL) ?
-		  global_system_variables.collation_server :
-		  thd->variables.collation_server);
+		  global_system_variables.*offset : thd->variables.*offset);
   return cs ? (byte*) cs->name : (byte*) "NULL";
 }
 
 
-void sys_var_collation_server::set_default(THD *thd, enum_var_type type)
-{
- if (type == OPT_GLOBAL)
-   global_system_variables.collation_server= default_charset_info;
- else
- {
-   thd->variables.collation_server= (global_system_variables.
-					 collation_server);
-   thd->update_charset();
- }
-}
-
-
 LEX_STRING default_key_cache_base= {(char *) "default", 7 };
 
 static KEY_CACHE zero_key_cache;
@@ -2804,52 +2297,6 @@ byte *sys_var_insert_id::value_ptr(THD *thd, enum_var_type type,
 }
 
 
-#ifdef HAVE_REPLICATION
-bool sys_var_slave_skip_counter::check(THD *thd, set_var *var)
-{
-  int result= 0;
-  pthread_mutex_lock(&LOCK_active_mi);
-  pthread_mutex_lock(&active_mi->rli.run_lock);
-  if (active_mi->rli.slave_running)
-  {
-    my_message(ER_SLAVE_MUST_STOP, ER(ER_SLAVE_MUST_STOP), MYF(0));
-    result=1;
-  }
-  pthread_mutex_unlock(&active_mi->rli.run_lock);
-  pthread_mutex_unlock(&LOCK_active_mi);
-  var->save_result.ulong_value= (ulong) var->value->val_int();
-  return result;
-}
-
-
-bool sys_var_slave_skip_counter::update(THD *thd, set_var *var)
-{
-  pthread_mutex_lock(&LOCK_active_mi);
-  pthread_mutex_lock(&active_mi->rli.run_lock);
-  /*
-    The following test should normally never be true as we test this
-    in the check function;  To be safe against multiple
-    SQL_SLAVE_SKIP_COUNTER request, we do the check anyway
-  */
-  if (!active_mi->rli.slave_running)
-  {
-    pthread_mutex_lock(&active_mi->rli.data_lock);
-    active_mi->rli.slave_skip_counter= var->save_result.ulong_value;
-    pthread_mutex_unlock(&active_mi->rli.data_lock);
-  }
-  pthread_mutex_unlock(&active_mi->rli.run_lock);
-  pthread_mutex_unlock(&LOCK_active_mi);
-  return 0;
-}
-
-
-bool sys_var_sync_binlog_period::update(THD *thd, set_var *var)
-{
-  sync_binlog_period= (ulong) var->save_result.ulonglong_value;
-  return 0;
-}
-#endif /* HAVE_REPLICATION */
-
 bool sys_var_rand_seed1::update(THD *thd, set_var *var)
 {
   thd->rand.seed1= (ulong) var->save_result.ulonglong_value;
@@ -3234,22 +2681,151 @@ static byte *get_sys_var_length(const sys_var *var, uint *length,
 
 
 /*
-  Initialises sys variables and put them in system_variable_hash
+  Add variables to the dynamic hash of system variables
+  
+  SYNOPSIS
+    mysql_add_sys_var_chain()
+    first       Pointer to first system variable to add
+    long_opt    (optional)command line arguments may be tied for limit checks.
+  
+  RETURN VALUES
+    0           SUCCESS
+    otherwise   FAILURE
 */
 
-
-void set_var_init()
+int mysql_add_sys_var_chain(sys_var *first, struct my_option *long_options)
 {
   sys_var *var;
-
-  hash_init(&system_variable_hash, system_charset_info, sys_var::sys_vars, 0,
-	    0, (hash_get_key) get_sys_var_length, 0, 0);
-  for (var= sys_var::first; var; var= var->next)
+  
+  /* A write lock should be held on LOCK_system_variables_hash */
+  
+  for (var= first; var; var= var->next)
   {
     var->name_length= strlen(var->name);
-    var->option_limits= find_option(my_long_options, var->name);
-    my_hash_insert(&system_variable_hash, (byte*) var);
+    /* this fails if there is a conflicting variable name. see HASH_UNIQUE */
+    if (my_hash_insert(&system_variable_hash, (byte*) var))
+      goto error;
+    if (long_options)
+      var->option_limits= find_option(long_options, var->name);
   }
+  return 0;
+
+error:
+  for (; first != var; first= first->next)
+    hash_delete(&system_variable_hash, (byte*) first);
+  return 1;
+}
+
+
+/*
+  Remove variables to the dynamic hash of system variables
+  
+  SYNOPSIS
+    mysql_del_sys_var_chain()
+    first       Pointer to first system variable to remove
+  
+  RETURN VALUES
+    0           SUCCESS
+    otherwise   FAILURE
+*/
+
+int mysql_del_sys_var_chain(sys_var *first)
+{
+  int result= 0;
+
+  /* A write lock should be held on LOCK_system_variables_hash */
+  
+  for (sys_var *var= first; var; var= var->next)
+    result|= hash_delete(&system_variable_hash, (byte*) var);
+
+  return result;
+}
+
+
+static int show_cmp(SHOW_VAR *a, SHOW_VAR *b)
+{
+  return strcmp(a->name, b->name);
+}
+
+
+/*
+  Constructs an array of system variables for display to the user.
+  
+  SYNOPSIS
+    enumerate_sys_vars()
+    thd         current thread
+    sorted      If TRUE, the system variables should be sorted
+  
+  RETURN VALUES
+    pointer     Array of SHOW_VAR elements for display
+    NULL        FAILURE
+*/
+
+SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted)
+{
+  int count= system_variable_hash.records, i;
+  int fixed_count= fixed_show_vars.elements;
+  int size= sizeof(SHOW_VAR) * (count + fixed_count + 1);
+  SHOW_VAR *result= (SHOW_VAR*) thd->alloc(size);
+
+  if (result)
+  {
+    SHOW_VAR *show= result + fixed_count;
+    memcpy(result, fixed_show_vars.buffer, fixed_count * sizeof(SHOW_VAR));
+
+    for (i= 0; i < count; i++)
+    {
+      sys_var *var= (sys_var*) hash_element(&system_variable_hash, i);
+      show->name= var->name;
+      show->value= (char*) var;
+      show->type= SHOW_SYS;
+      show++;
+    }
+
+    /* sort into order */
+    if (sorted)
+      qsort(result, count + fixed_count, sizeof(SHOW_VAR), (qsort_cmp)show_cmp);
+    
+    /* make last element empty */
+    bzero(show, sizeof(SHOW_VAR));
+  }
+  return result;
+}
+
+
+/*
+  Initialize the system variables
+  
+  SYNOPSIS
+    set_var_init()
+  
+  RETURN VALUES
+    0           SUCCESS
+    otherwise   FAILURE
+*/
+
+int set_var_init()
+{
+  uint count= 0;
+  DBUG_ENTER("set_var_init");
+  
+  for (sys_var *var=vars.first; var; var= var->next, count++);
+
+  if (my_init_dynamic_array(&fixed_show_vars, sizeof(SHOW_VAR),
+                            FIXED_VARS_SIZE + 64, 64))
+    goto error;
+
+  fixed_show_vars.elements= FIXED_VARS_SIZE;
+  memcpy(fixed_show_vars.buffer, fixed_vars, sizeof(fixed_vars));
+
+  if (hash_init(&system_variable_hash, system_charset_info, count, 0,
+                0, (hash_get_key) get_sys_var_length, 0, HASH_UNIQUE))
+    goto error;
+
+  vars.last->next= NULL;
+  if (mysql_add_sys_var_chain(vars.first, my_long_options))
+    goto error;
+
   /*
     Special cases
     Needed because MySQL can't find the limits for a variable it it has
@@ -3257,12 +2833,41 @@ void set_var_init()
     As these variables are deprecated, this code will disappear soon...
   */
   sys_sql_max_join_size.option_limits= sys_max_join_size.option_limits;
+
+  DBUG_RETURN(0);
+
+error:
+  fprintf(stderr, "failed to initialize system variables");
+  pthread_mutex_unlock(&LOCK_global_system_variables);
+  DBUG_RETURN(1);
 }
 
 
 void set_var_free()
 {
   hash_free(&system_variable_hash);
+  delete_dynamic(&fixed_show_vars);
+}
+
+
+/*
+  Add elements to the dynamic list of read-only system variables.
+  
+  SYNOPSIS
+    mysql_append_static_vars()
+    show_vars	Pointer to start of array
+    count       Number of elements
+  
+  RETURN VALUES
+    0           SUCCESS
+    otherwise   FAILURE
+*/
+int mysql_append_static_vars(const SHOW_VAR *show_vars, uint count)
+{
+  for (; count > 0; count--, show_vars++)
+    if (insert_dynamic(&fixed_show_vars, (char*) show_vars))
+      return 1;
+  return 0;
 }
 
 
@@ -3270,7 +2875,7 @@ void set_var_free()
   Find a user set-table variable
 
   SYNOPSIS
-    find_sys_var()
+    intern_find_sys_var()
     str		Name of system variable to find
     length	Length of variable.  zero means that we should use strlen()
 		on the variable
@@ -3280,14 +2885,19 @@ void set_var_free()
     0		Unknown variable (error message is given)
 */
 
-sys_var *find_sys_var(const char *str, uint length)
+sys_var *intern_find_sys_var(const char *str, uint length, bool no_error)
 {
-  sys_var *var= (sys_var*) hash_search(&system_variable_hash,
-				       (byte*) str,
-				       length ? length :
-				       strlen(str));
-  if (!var)
+  sys_var *var;
+
+  /*
+    This function is only called from the sql_plugin.cc.
+    A lock on LOCK_system_variable_hash should be held
+  */
+  var= (sys_var*) hash_search(&system_variable_hash,
+			      (byte*) str, length ? length : strlen(str));
+  if (!(var || no_error))
     my_error(ER_UNKNOWN_SYSTEM_VARIABLE, MYF(0), (char*) str);
+
   return var;
 }
 
@@ -3553,14 +3163,16 @@ bool sys_var_thd_storage_engine::check(THD *thd, set_var *var)
   const char *value;
   String str(buff, sizeof(buff), &my_charset_latin1), *res;
 
+  var->save_result.plugin= NULL;
   if (var->value->result_type() == STRING_RESULT)
   {
     LEX_STRING name;
-    handlerton *db_type;
+    handlerton *hton;
     if (!(res=var->value->val_str(&str)) ||
         !(name.str= (char *)res->ptr()) || !(name.length= res->length()) ||
-	!(var->save_result.hton= db_type= ha_resolve_by_name(thd, &name)) ||
-        ha_checktype(thd, ha_legacy_type(db_type), 1, 0) != db_type)
+	!(var->save_result.plugin= ha_resolve_by_name(thd, &name)) ||
+        !(hton= plugin_data(var->save_result.plugin, handlerton *)) ||
+        ha_checktype(thd, ha_legacy_type(hton), 1, 0) != hton)
     {
       value= res ? res->c_ptr() : "NULL";
       goto err;
@@ -3578,28 +3190,52 @@ err:
 byte *sys_var_thd_storage_engine::value_ptr(THD *thd, enum_var_type type,
 					    LEX_STRING *base)
 {
-  handlerton *val;
-  val= (type == OPT_GLOBAL) ? global_system_variables.*offset :
-        thd->variables.*offset;
-  return (byte *) hton2plugin[val->slot]->name.str;
+  byte* result;
+  handlerton *hton;
+  LEX_STRING *name;
+  plugin_ref plugin= thd->variables.*offset;
+  if (type == OPT_GLOBAL)
+    plugin= my_plugin_lock(thd, &(global_system_variables.*offset));
+  hton= plugin_data(plugin, handlerton*);
+  name= &hton2plugin[hton->slot]->name;
+  result= (byte *) thd->strmake(name->str, name->length);
+  if (type == OPT_GLOBAL)
+    plugin_unlock(thd, plugin);
+  return result;
 }
 
 
 void sys_var_thd_storage_engine::set_default(THD *thd, enum_var_type type)
 {
+  plugin_ref old_value, new_value, *value;
   if (type == OPT_GLOBAL)
-    global_system_variables.*offset= myisam_hton;
+  {
+    value= &(global_system_variables.*offset);
+    new_value= ha_lock_engine(NULL, myisam_hton);
+  }
   else
-    thd->variables.*offset= global_system_variables.*offset;
+  {
+    value= &(thd->variables.*offset);
+    new_value= my_plugin_lock(NULL, &(global_system_variables.*offset));
+  }
+  DBUG_ASSERT(new_value);
+  old_value= *value;
+  *value= new_value;
+  plugin_unlock(NULL, old_value);
 }
 
 
 bool sys_var_thd_storage_engine::update(THD *thd, set_var *var)
 {
-  handlerton **value= &(global_system_variables.*offset);
-  if (var->type != OPT_GLOBAL)
-    value= &(thd->variables.*offset);
-  *value= var->save_result.hton;
+  plugin_ref *value= &(global_system_variables.*offset), old_value;
+   if (var->type != OPT_GLOBAL)
+     value= &(thd->variables.*offset);
+  old_value= *value;
+  if (old_value != var->save_result.plugin)
+  {
+    *value= my_plugin_lock(NULL, &var->save_result.plugin);
+    plugin_unlock(NULL, old_value);
+  }
   return 0;
 }
 
diff --git a/sql/set_var.h b/sql/set_var.h
index 8887d91ec69..2813a756b8e 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -26,6 +26,7 @@
 
 class sys_var;
 class set_var;
+class sys_var_pluginvar; /* opaque */
 typedef struct system_variables SV;
 typedef struct my_locale_st MY_LOCALE;
 
@@ -37,11 +38,15 @@ typedef void (*sys_after_update_func)(THD *,enum_var_type);
 typedef void (*sys_set_default_func)(THD *, enum_var_type);
 typedef byte *(*sys_value_ptr_func)(THD *thd);
 
+struct sys_var_chain
+{
+  sys_var *first;
+  sys_var *last;
+};
+
 class sys_var
 {
 public:
-  static sys_var *first;
-  static uint sys_vars;
   sys_var *next;
   struct my_option *option_limits;	/* Updated by by set_var_init() */
   uint name_length;			/* Updated by by set_var_init() */
@@ -52,13 +57,15 @@ public:
   sys_var(const char *name_arg,sys_after_update_func func= NULL)
     :name(name_arg), after_update(func)
     , no_support_one_shot(1)
-  { add_sys_var(); }
+  {}
   virtual ~sys_var() {}
-  void add_sys_var()
+  void chain_sys_var(sys_var_chain *chain_arg)
   {
-    next= first;
-    first= this;
-    sys_vars++;
+    if (chain_arg->last)
+      chain_arg->last->next= this;
+    else
+      chain_arg->first= this;
+    chain_arg->last= this;
   }
   virtual bool check(THD *thd, set_var *var);
   bool check_enum(THD *thd, set_var *var, TYPELIB *enum_names);
@@ -77,6 +84,7 @@ public:
   Item *item(THD *thd, enum_var_type type, LEX_STRING *base);
   virtual bool is_struct() { return 0; }
   virtual bool is_readonly() const { return 0; }
+  virtual sys_var_pluginvar *cast_pluginvar() { return 0; }
 };
 
 
@@ -105,12 +113,12 @@ class sys_var_long_ptr_global: public sys_var_global
 {
 public:
   ulong *value;
-  sys_var_long_ptr_global(const char *name_arg, ulong *value_ptr_arg,
+  sys_var_long_ptr_global(sys_var_chain *chain, const char *name_arg, ulong *value_ptr_arg,
                         pthread_mutex_t *guard_arg,
                         sys_after_update_func after_update_arg= NULL)
     :sys_var_global(name_arg, after_update_arg, guard_arg),
     value(value_ptr_arg)
-    {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
@@ -127,7 +135,7 @@ public:
 class sys_var_long_ptr :public sys_var_long_ptr_global
 {
 public:
-  sys_var_long_ptr(const char *name_arg, ulong *value_ptr,
+  sys_var_long_ptr(sys_var_chain *chain, const char *name_arg, ulong *value_ptr,
                    sys_after_update_func after_update_arg= NULL);
 };
 
@@ -136,11 +144,13 @@ class sys_var_ulonglong_ptr :public sys_var
 {
 public:
   ulonglong *value;
-  sys_var_ulonglong_ptr(const char *name_arg, ulonglong *value_ptr_arg)
-    :sys_var(name_arg),value(value_ptr_arg) {}
-  sys_var_ulonglong_ptr(const char *name_arg, ulonglong *value_ptr_arg,
+  sys_var_ulonglong_ptr(sys_var_chain *chain, const char *name_arg, ulonglong *value_ptr_arg)
+    :sys_var(name_arg),value(value_ptr_arg)
+  { chain_sys_var(chain); }
+  sys_var_ulonglong_ptr(sys_var_chain *chain, const char *name_arg, ulonglong *value_ptr_arg,
 		       sys_after_update_func func)
-    :sys_var(name_arg,func), value(value_ptr_arg) {}
+    :sys_var(name_arg,func), value(value_ptr_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
@@ -153,9 +163,9 @@ class sys_var_bool_ptr :public sys_var
 {
 public:
   my_bool *value;
-  sys_var_bool_ptr(const char *name_arg, my_bool *value_arg)
+  sys_var_bool_ptr(sys_var_chain *chain, const char *name_arg, my_bool *value_arg)
     :sys_var(name_arg),value(value_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     return check_enum(thd, var, &bool_typelib);
@@ -177,14 +187,14 @@ public:
   sys_check_func check_func;
   sys_update_func update_func;
   sys_set_default_func set_default_func;
-  sys_var_str(const char *name_arg,
+  sys_var_str(sys_var_chain *chain, const char *name_arg,
 	      sys_check_func check_func_arg,
 	      sys_update_func update_func_arg,
 	      sys_set_default_func set_default_func_arg,
               char *value_arg)
     :sys_var(name_arg), value(value_arg), check_func(check_func_arg),
     update_func(update_func_arg),set_default_func(set_default_func_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   bool update(THD *thd, set_var *var)
   {
@@ -209,9 +219,9 @@ class sys_var_const_str :public sys_var
 {
 public:
   char *value;					// Pointer to const value
-  sys_var_const_str(const char *name_arg, const char *value_arg)
+  sys_var_const_str(sys_var_chain *chain, const char *name_arg, const char *value_arg)
     :sys_var(name_arg),value((char*) value_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     return 1;
@@ -238,9 +248,9 @@ class sys_var_const_str_ptr :public sys_var
 {
 public:
   char **value;					// Pointer to const value
-  sys_var_const_str_ptr(const char *name_arg, char **value_arg)
+  sys_var_const_str_ptr(sys_var_chain *chain, const char *name_arg, char **value_arg)
     :sys_var(name_arg),value(value_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     return 1;
@@ -268,10 +278,10 @@ class sys_var_enum :public sys_var
   uint *value;
   TYPELIB *enum_names;
 public:
-  sys_var_enum(const char *name_arg, uint *value_arg,
+  sys_var_enum(sys_var_chain *chain, const char *name_arg, uint *value_arg,
 	       TYPELIB *typelib, sys_after_update_func func)
     :sys_var(name_arg,func), value(value_arg), enum_names(typelib)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     return check_enum(thd, var, enum_names);
@@ -286,7 +296,8 @@ public:
 class sys_var_thd :public sys_var
 {
 public:
-  sys_var_thd(const char *name_arg, sys_after_update_func func= NULL)
+  sys_var_thd(const char *name_arg, 
+              sys_after_update_func func= NULL)
     :sys_var(name_arg,func)
   {}
   bool check_type(enum_var_type type) { return 0; }
@@ -302,13 +313,13 @@ class sys_var_thd_ulong :public sys_var_thd
   sys_check_func check_func;
 public:
   ulong SV::*offset;
-  sys_var_thd_ulong(const char *name_arg, ulong SV::*offset_arg)
+  sys_var_thd_ulong(sys_var_chain *chain, const char *name_arg, ulong SV::*offset_arg)
     :sys_var_thd(name_arg), check_func(0), offset(offset_arg)
-  {}
-  sys_var_thd_ulong(const char *name_arg, ulong SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_ulong(sys_var_chain *chain, const char *name_arg, ulong SV::*offset_arg,
 		   sys_check_func c_func, sys_after_update_func au_func)
     :sys_var_thd(name_arg,au_func), check_func(c_func), offset(offset_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
@@ -321,13 +332,15 @@ class sys_var_thd_ha_rows :public sys_var_thd
 {
 public:
   ha_rows SV::*offset;
-  sys_var_thd_ha_rows(const char *name_arg, ha_rows SV::*offset_arg)
+  sys_var_thd_ha_rows(sys_var_chain *chain, const char *name_arg, 
+                      ha_rows SV::*offset_arg)
     :sys_var_thd(name_arg), offset(offset_arg)
-  {}
-  sys_var_thd_ha_rows(const char *name_arg, ha_rows SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_ha_rows(sys_var_chain *chain, const char *name_arg, 
+                      ha_rows SV::*offset_arg,
 		      sys_after_update_func func)
     :sys_var_thd(name_arg,func), offset(offset_arg)
-  {}
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   SHOW_TYPE show_type() { return SHOW_HA_ROWS; }
@@ -340,14 +353,16 @@ class sys_var_thd_ulonglong :public sys_var_thd
 public:
   ulonglong SV::*offset;
   bool only_global;
-  sys_var_thd_ulonglong(const char *name_arg, ulonglong SV::*offset_arg)
+  sys_var_thd_ulonglong(sys_var_chain *chain, const char *name_arg, 
+                        ulonglong SV::*offset_arg)
     :sys_var_thd(name_arg), offset(offset_arg)
-  {}
-  sys_var_thd_ulonglong(const char *name_arg, ulonglong SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_ulonglong(sys_var_chain *chain, const char *name_arg, 
+                        ulonglong SV::*offset_arg,
 			sys_after_update_func func, bool only_global_arg)
     :sys_var_thd(name_arg, func), offset(offset_arg),
     only_global(only_global_arg)
-  {}
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
@@ -367,13 +382,13 @@ class sys_var_thd_bool :public sys_var_thd
 {
 public:
   my_bool SV::*offset;
-  sys_var_thd_bool(const char *name_arg, my_bool SV::*offset_arg)
+  sys_var_thd_bool(sys_var_chain *chain, const char *name_arg, my_bool SV::*offset_arg)
     :sys_var_thd(name_arg), offset(offset_arg)
-  {}
-  sys_var_thd_bool(const char *name_arg, my_bool SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_bool(sys_var_chain *chain, const char *name_arg, my_bool SV::*offset_arg,
 		   sys_after_update_func func)
     :sys_var_thd(name_arg,func), offset(offset_arg)
-  {}
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   SHOW_TYPE show_type() { return SHOW_MY_BOOL; }
@@ -393,23 +408,23 @@ protected:
   TYPELIB *enum_names;
   sys_check_func check_func;
 public:
-  sys_var_thd_enum(const char *name_arg, ulong SV::*offset_arg,
+  sys_var_thd_enum(sys_var_chain *chain, const char *name_arg, ulong SV::*offset_arg,
 		   TYPELIB *typelib)
     :sys_var_thd(name_arg), offset(offset_arg), enum_names(typelib),
     check_func(0)
-  {}
-  sys_var_thd_enum(const char *name_arg, ulong SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_enum(sys_var_chain *chain, const char *name_arg, ulong SV::*offset_arg,
 		   TYPELIB *typelib,
 		   sys_after_update_func func)
     :sys_var_thd(name_arg,func), offset(offset_arg), enum_names(typelib),
     check_func(0)
-  {}
-  sys_var_thd_enum(const char *name_arg, ulong SV::*offset_arg,
+  { chain_sys_var(chain); }
+  sys_var_thd_enum(sys_var_chain *chain, const char *name_arg, ulong SV::*offset_arg,
 		   TYPELIB *typelib, sys_after_update_func func,
                    sys_check_func check)
     :sys_var_thd(name_arg,func), offset(offset_arg), enum_names(typelib),
     check_func(check)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     int ret= 0;
@@ -430,8 +445,9 @@ extern void fix_sql_mode_var(THD *thd, enum_var_type type);
 class sys_var_thd_sql_mode :public sys_var_thd_enum
 {
 public:
-  sys_var_thd_sql_mode(const char *name_arg, ulong SV::*offset_arg)
-    :sys_var_thd_enum(name_arg, offset_arg, &sql_mode_typelib,
+  sys_var_thd_sql_mode(sys_var_chain *chain, const char *name_arg, 
+                       ulong SV::*offset_arg)
+    :sys_var_thd_enum(chain, name_arg, offset_arg, &sql_mode_typelib,
 		      fix_sql_mode_var)
   {}
   bool check(THD *thd, set_var *var)
@@ -448,11 +464,12 @@ public:
 class sys_var_thd_storage_engine :public sys_var_thd
 {
 protected:
-  handlerton *SV::*offset;
+  plugin_ref SV::*offset;
 public:
-  sys_var_thd_storage_engine(const char *name_arg, handlerton *SV::*offset_arg)
+  sys_var_thd_storage_engine(sys_var_chain *chain, const char *name_arg, 
+                             plugin_ref SV::*offset_arg)
     :sys_var_thd(name_arg), offset(offset_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_CHAR; }
   bool check_update_type(Item_result type)
@@ -467,8 +484,9 @@ public:
 class sys_var_thd_table_type :public sys_var_thd_storage_engine
 {
 public:
-  sys_var_thd_table_type(const char *name_arg, handlerton *SV::*offset_arg)
-    :sys_var_thd_storage_engine(name_arg, offset_arg)
+  sys_var_thd_table_type(sys_var_chain *chain, const char *name_arg, 
+                         plugin_ref SV::*offset_arg)
+    :sys_var_thd_storage_engine(chain, name_arg, offset_arg)
   {}
   void warn_deprecated(THD *thd);
   void set_default(THD *thd, enum_var_type type);
@@ -482,12 +500,12 @@ class sys_var_thd_bit :public sys_var_thd
 public:
   ulonglong bit_flag;
   bool reverse;
-  sys_var_thd_bit(const char *name_arg,
+  sys_var_thd_bit(sys_var_chain *chain, const char *name_arg,
                   sys_check_func c_func, sys_update_func u_func,
                   ulonglong bit, bool reverse_arg=0)
     :sys_var_thd(name_arg), check_func(c_func), update_func(u_func),
     bit_flag(bit), reverse(reverse_arg)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   bool update(THD *thd, set_var *var);
   bool check_update_type(Item_result type) { return 0; }
@@ -499,7 +517,9 @@ public:
 class sys_var_thd_dbug :public sys_var_thd
 {
 public:
-  sys_var_thd_dbug(const char *name_arg) :sys_var_thd(name_arg) {}
+  sys_var_thd_dbug(sys_var_chain *chain, const char *name_arg)
+    :sys_var_thd(name_arg)
+  { chain_sys_var(chain); }
   bool check_update_type(Item_result type) { return type != STRING_RESULT; }
   bool check(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_CHAR; }
@@ -515,7 +535,9 @@ public:
 class sys_var_timestamp :public sys_var
 {
 public:
-  sys_var_timestamp(const char *name_arg) :sys_var(name_arg) {}
+  sys_var_timestamp(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   bool check_type(enum_var_type type)    { return type == OPT_GLOBAL; }
@@ -528,7 +550,9 @@ public:
 class sys_var_last_insert_id :public sys_var
 {
 public:
-  sys_var_last_insert_id(const char *name_arg) :sys_var(name_arg) {}
+  sys_var_last_insert_id(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   bool check_type(enum_var_type type) { return type == OPT_GLOBAL; }
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
@@ -539,7 +563,9 @@ public:
 class sys_var_insert_id :public sys_var
 {
 public:
-  sys_var_insert_id(const char *name_arg) :sys_var(name_arg) {}
+  sys_var_insert_id(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   bool check_type(enum_var_type type) { return type == OPT_GLOBAL; }
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
@@ -547,33 +573,12 @@ public:
 };
 
 
-#ifdef HAVE_REPLICATION
-class sys_var_slave_skip_counter :public sys_var
-{
-public:
-  sys_var_slave_skip_counter(const char *name_arg) :sys_var(name_arg) {}
-  bool check(THD *thd, set_var *var);
-  bool update(THD *thd, set_var *var);
-  bool check_type(enum_var_type type) { return type != OPT_GLOBAL; }
-  /*
-    We can't retrieve the value of this, so we don't have to define
-    show_type() or value_ptr()
-  */
-};
-
-class sys_var_sync_binlog_period :public sys_var_long_ptr
-{
-public:
-  sys_var_sync_binlog_period(const char *name_arg, ulong *value_ptr_arg)
-    :sys_var_long_ptr(name_arg,value_ptr_arg) {}
-  bool update(THD *thd, set_var *var);
-};
-#endif
-
 class sys_var_rand_seed1 :public sys_var
 {
 public:
-  sys_var_rand_seed1(const char *name_arg) :sys_var(name_arg) {}
+  sys_var_rand_seed1(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   bool check_type(enum_var_type type) { return type == OPT_GLOBAL; }
 };
@@ -581,7 +586,9 @@ public:
 class sys_var_rand_seed2 :public sys_var
 {
 public:
-  sys_var_rand_seed2(const char *name_arg) :sys_var(name_arg) {}
+  sys_var_rand_seed2(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var);
   bool check_type(enum_var_type type) { return type == OPT_GLOBAL; }
 };
@@ -590,7 +597,8 @@ public:
 class sys_var_collation :public sys_var_thd
 {
 public:
-  sys_var_collation(const char *name_arg) :sys_var_thd(name_arg)
+  sys_var_collation(const char *name_arg)
+    :sys_var_thd(name_arg)
     {
     no_support_one_shot= 0;
     }
@@ -608,10 +616,9 @@ class sys_var_character_set :public sys_var_thd
 {
 public:
   bool nullable;
-  sys_var_character_set(const char *name_arg) :
-    sys_var_thd(name_arg)
+  sys_var_character_set(const char *name_arg, bool is_nullable= 0) :
+    sys_var_thd(name_arg), nullable(is_nullable)
   {
-    nullable= 0;
     /*
       In fact only almost all variables derived from sys_var_character_set
       support ONE_SHOT; character_set_results doesn't. But that's good enough.
@@ -631,83 +638,47 @@ public:
   virtual CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type)= 0;
 };
 
-class sys_var_character_set_filesystem :public sys_var_character_set
-{
-public:
-  sys_var_character_set_filesystem(const char *name_arg) :
-    sys_var_character_set(name_arg) {}
-  void set_default(THD *thd, enum_var_type type);
-  CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
-};
-
-class sys_var_character_set_client :public sys_var_character_set
-{
-public:
-  sys_var_character_set_client(const char *name_arg) :
-    sys_var_character_set(name_arg) {}
-  void set_default(THD *thd, enum_var_type type);
-  CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
-};
 
-class sys_var_character_set_results :public sys_var_character_set
+class sys_var_character_set_sv :public sys_var_character_set
 {
+  CHARSET_INFO **global_default;
+  CHARSET_INFO *SV::*offset;
 public:
-  sys_var_character_set_results(const char *name_arg) :
-    sys_var_character_set(name_arg) 
-    { nullable= 1; }
+  sys_var_character_set_sv(sys_var_chain *chain, const char *name_arg,
+                            CHARSET_INFO *SV::*offset_arg,
+                            CHARSET_INFO **global_default_arg, 
+                            bool is_nullable= 0)
+    : sys_var_character_set(name_arg, is_nullable),
+      offset(offset_arg), global_default(global_default_arg)
+  { chain_sys_var(chain); }
   void set_default(THD *thd, enum_var_type type);
   CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
 };
 
-class sys_var_character_set_server :public sys_var_character_set
-{
-public:
-  sys_var_character_set_server(const char *name_arg) :
-    sys_var_character_set(name_arg) {}
-  void set_default(THD *thd, enum_var_type type);
-  CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
-};
 
 class sys_var_character_set_database :public sys_var_character_set
 {
 public:
-  sys_var_character_set_database(const char *name_arg) :
-    sys_var_character_set(name_arg) {}
+  sys_var_character_set_database(sys_var_chain *chain, const char *name_arg) :
+    sys_var_character_set(name_arg)
+  { chain_sys_var(chain); }
   void set_default(THD *thd, enum_var_type type);
   CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
 };
 
-class sys_var_character_set_connection :public sys_var_character_set
+class sys_var_collation_sv :public sys_var_collation
 {
+  CHARSET_INFO **global_default;
+  CHARSET_INFO *SV::*offset;
 public:
-  sys_var_character_set_connection(const char *name_arg) :
-    sys_var_character_set(name_arg) {}
-  void set_default(THD *thd, enum_var_type type);
-  CHARSET_INFO **ci_ptr(THD *thd, enum_var_type type);
-};
-
-class sys_var_collation_connection :public sys_var_collation
-{
-public:
-  sys_var_collation_connection(const char *name_arg) :sys_var_collation(name_arg) {}
-  bool update(THD *thd, set_var *var);
-  void set_default(THD *thd, enum_var_type type);
-  byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
-};
-
-class sys_var_collation_server :public sys_var_collation
-{
-public:
-  sys_var_collation_server(const char *name_arg) :sys_var_collation(name_arg) {}
-  bool update(THD *thd, set_var *var);
-  void set_default(THD *thd, enum_var_type type);
-  byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
-};
-
-class sys_var_collation_database :public sys_var_collation
-{
-public:
-  sys_var_collation_database(const char *name_arg) :sys_var_collation(name_arg) {}
+  sys_var_collation_sv(sys_var_chain *chain, const char *name_arg,
+                               CHARSET_INFO *SV::*offset_arg,
+                               CHARSET_INFO **global_default_arg)
+    :sys_var_collation(name_arg),
+     offset(offset_arg), global_default(global_default_arg)
+  {
+    chain_sys_var(chain);
+  }
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
@@ -719,9 +690,10 @@ class sys_var_key_cache_param :public sys_var
 protected:
   size_t offset;
 public:
-  sys_var_key_cache_param(const char *name_arg, size_t offset_arg)
+  sys_var_key_cache_param(sys_var_chain *chain, const char *name_arg, 
+                          size_t offset_arg)
     :sys_var(name_arg), offset(offset_arg)
-  {}
+  { chain_sys_var(chain); }
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
   bool check_default(enum_var_type type) { return 1; }
   bool is_struct() { return 1; }
@@ -731,8 +703,9 @@ public:
 class sys_var_key_buffer_size :public sys_var_key_cache_param
 {
 public:
-  sys_var_key_buffer_size(const char *name_arg)
-    :sys_var_key_cache_param(name_arg, offsetof(KEY_CACHE, param_buff_size))
+  sys_var_key_buffer_size(sys_var_chain *chain, const char *name_arg)
+    :sys_var_key_cache_param(chain, name_arg,
+                             offsetof(KEY_CACHE, param_buff_size))
   {}
   bool update(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
@@ -742,8 +715,8 @@ public:
 class sys_var_key_cache_long :public sys_var_key_cache_param
 {
 public:
-  sys_var_key_cache_long(const char *name_arg, size_t offset_arg)
-    :sys_var_key_cache_param(name_arg, offset_arg)
+  sys_var_key_cache_long(sys_var_chain *chain, const char *name_arg, size_t offset_arg)
+    :sys_var_key_cache_param(chain, name_arg, offset_arg)
   {}
   bool update(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_LONG; }
@@ -755,12 +728,12 @@ class sys_var_thd_date_time_format :public sys_var_thd
   DATE_TIME_FORMAT *SV::*offset;
   timestamp_type date_time_type;
 public:
-  sys_var_thd_date_time_format(const char *name_arg,
+  sys_var_thd_date_time_format(sys_var_chain *chain, const char *name_arg,
 			       DATE_TIME_FORMAT *SV::*offset_arg,
 			       timestamp_type date_time_type_arg)
     :sys_var_thd(name_arg), offset(offset_arg),
     date_time_type(date_time_type_arg)
-  {}
+  { chain_sys_var(chain); }
   SHOW_TYPE show_type() { return SHOW_CHAR; }
   bool check_update_type(Item_result type)
   {
@@ -779,8 +752,9 @@ class sys_var_log_state :public sys_var_bool_ptr
 {
   uint log_type;
 public:
-  sys_var_log_state(const char *name_arg, my_bool *value_arg, uint log_type_arg)
-    :sys_var_bool_ptr(name_arg, value_arg), log_type(log_type_arg) {}
+  sys_var_log_state(sys_var_chain *chain, const char *name_arg, my_bool *value_arg, 
+                    uint log_type_arg)
+    :sys_var_bool_ptr(chain, name_arg, value_arg), log_type(log_type_arg) {}
   bool update(THD *thd, set_var *var);
   void set_default(THD *thd, enum_var_type type);
 };
@@ -791,10 +765,10 @@ class sys_var_log_output :public sys_var
   ulong *value;
   TYPELIB *enum_names;
 public:
-  sys_var_log_output(const char *name_arg, ulong *value_arg,
+  sys_var_log_output(sys_var_chain *chain, const char *name_arg, ulong *value_arg,
                      TYPELIB *typelib, sys_after_update_func func)
     :sys_var(name_arg,func), value(value_arg), enum_names(typelib)
-  {}
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var)
   {
     return check_set(thd, var, enum_names);
@@ -815,12 +789,12 @@ public:
   enum_var_type var_type;
   SHOW_TYPE show_type_value;
   sys_value_ptr_func value_ptr_func;
-  sys_var_readonly(const char *name_arg, enum_var_type type,
+  sys_var_readonly(sys_var_chain *chain, const char *name_arg, enum_var_type type,
 		   SHOW_TYPE show_type_arg,
 		   sys_value_ptr_func value_ptr_func_arg)
     :sys_var(name_arg), var_type(type), 
        show_type_value(show_type_arg), value_ptr_func(value_ptr_func_arg)
-  {}
+  { chain_sys_var(chain); }
   bool update(THD *thd, set_var *var) { return 1; }
   bool check_default(enum_var_type type) { return 1; }
   bool check_type(enum_var_type type) { return type != var_type; }
@@ -834,19 +808,17 @@ public:
 };
 
 
-class sys_var_have_variable: public sys_var
+class sys_var_have_option: public sys_var
 {
-  SHOW_COMP_OPTION *have_variable;
-
+protected:
+  virtual SHOW_COMP_OPTION get_option() = 0;
 public:
-  sys_var_have_variable(const char *variable_name,
-                        SHOW_COMP_OPTION *have_variable_arg):
-    sys_var(variable_name),
-    have_variable(have_variable_arg)
-  { }
+  sys_var_have_option(sys_var_chain *chain, const char *variable_name):
+    sys_var(variable_name)
+  { chain_sys_var(chain); }
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
   {
-    return (byte*) show_comp_option_name[*have_variable];
+    return (byte*) show_comp_option_name[get_option()];
   }
   bool update(THD *thd, set_var *var) { return 1; }
   bool check_default(enum_var_type type) { return 1; }
@@ -857,13 +829,47 @@ public:
 };
 
 
+class sys_var_have_variable: public sys_var_have_option
+{
+  SHOW_COMP_OPTION *have_variable;
+
+public:
+  sys_var_have_variable(sys_var_chain *chain, const char *variable_name,
+                        SHOW_COMP_OPTION *have_variable_arg):
+    sys_var_have_option(chain, variable_name),
+    have_variable(have_variable_arg)
+  { }
+  SHOW_COMP_OPTION get_option() { return *have_variable; }
+};
+
+
+class sys_var_have_plugin: public sys_var_have_option
+{
+  const char *plugin_name_str;
+  const uint plugin_name_len;
+  const int plugin_type;
+
+public:
+  sys_var_have_plugin(sys_var_chain *chain, const char *variable_name,
+                      const char *plugin_name_str_arg, uint plugin_name_len_arg, 
+                      int plugin_type_arg):
+    sys_var_have_option(chain, variable_name), 
+    plugin_name_str(plugin_name_str_arg), plugin_name_len(plugin_name_len_arg),
+    plugin_type(plugin_type_arg)
+  { }
+  /* the following method is declared in sql_plugin.cc */
+  SHOW_COMP_OPTION get_option();
+};
+
+
 class sys_var_thd_time_zone :public sys_var_thd
 {
 public:
-  sys_var_thd_time_zone(const char *name_arg):
+  sys_var_thd_time_zone(sys_var_chain *chain, const char *name_arg):
     sys_var_thd(name_arg) 
   {
     no_support_one_shot= 0;
+    chain_sys_var(chain);
   }
   bool check(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_CHAR; }
@@ -881,8 +887,9 @@ public:
 class sys_var_max_user_conn : public sys_var_thd
 {
 public:
-  sys_var_max_user_conn(const char *name_arg):
-    sys_var_thd(name_arg) {}
+  sys_var_max_user_conn(sys_var_chain *chain, const char *name_arg):
+    sys_var_thd(name_arg)
+  { chain_sys_var(chain); }
   bool check(THD *thd, set_var *var);
   bool update(THD *thd, set_var *var);
   bool check_default(enum_var_type type)
@@ -898,8 +905,9 @@ class sys_var_trust_routine_creators :public sys_var_bool_ptr
 {
   /* We need a derived class only to have a warn_deprecated() */
 public:
-  sys_var_trust_routine_creators(const char *name_arg, my_bool *value_arg) :
-    sys_var_bool_ptr(name_arg, value_arg) {};
+  sys_var_trust_routine_creators(sys_var_chain *chain, const char *name_arg, 
+                                 my_bool *value_arg) :
+    sys_var_bool_ptr(chain, name_arg, value_arg) {};
   void warn_deprecated(THD *thd);
   void set_default(THD *thd, enum_var_type type);
   bool update(THD *thd, set_var *var);
@@ -913,8 +921,9 @@ public:
 class sys_var_opt_readonly :public sys_var_bool_ptr
 {
 public:
-  sys_var_opt_readonly(const char *name_arg, my_bool *value_arg) :
-    sys_var_bool_ptr(name_arg, value_arg) {};
+  sys_var_opt_readonly(sys_var_chain *chain, const char *name_arg, 
+                       my_bool *value_arg) :
+    sys_var_bool_ptr(chain, name_arg, value_arg) {};
   ~sys_var_opt_readonly() {};
   bool update(THD *thd, set_var *var);
 };
@@ -923,12 +932,13 @@ public:
 class sys_var_thd_lc_time_names :public sys_var_thd
 {
 public:
-  sys_var_thd_lc_time_names(const char *name_arg):
-    sys_var_thd(name_arg) 
+  sys_var_thd_lc_time_names(sys_var_chain *chain, const char *name_arg):
+    sys_var_thd(name_arg)
   {
 #if MYSQL_VERSION_ID < 50000
     no_support_one_shot= 0;
 #endif
+    chain_sys_var(chain);
   }
   bool check(THD *thd, set_var *var);
   SHOW_TYPE show_type() { return SHOW_CHAR; }
@@ -947,8 +957,8 @@ class sys_var_event_scheduler :public sys_var_long_ptr
 {
   /* We need a derived class only to have a warn_deprecated() */
 public:
-  sys_var_event_scheduler(const char *name_arg) :
-    sys_var_long_ptr(name_arg, NULL, NULL) {};
+  sys_var_event_scheduler(sys_var_chain *chain, const char *name_arg) :
+    sys_var_long_ptr(chain, name_arg, NULL, NULL) {};
   bool update(THD *thd, set_var *var);
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
   SHOW_TYPE show_type() { return SHOW_CHAR; }
@@ -964,8 +974,9 @@ extern void fix_binlog_format_after_update(THD *thd, enum_var_type type);
 class sys_var_thd_binlog_format :public sys_var_thd_enum
 {
 public:
-  sys_var_thd_binlog_format(const char *name_arg, ulong SV::*offset_arg)
-    :sys_var_thd_enum(name_arg, offset_arg,
+  sys_var_thd_binlog_format(sys_var_chain *chain, const char *name_arg, 
+                            ulong SV::*offset_arg)
+    :sys_var_thd_enum(chain, name_arg, offset_arg,
                       &binlog_format_typelib
                       , fix_binlog_format_after_update
                       )
@@ -1003,7 +1014,7 @@ public:
     CHARSET_INFO *charset;
     ulong ulong_value;
     ulonglong ulonglong_value;
-    handlerton *hton;
+    plugin_ref plugin;
     DATE_TIME_FORMAT *date_time_format;
     Time_zone *time_zone;
     MY_LOCALE *locale_value;
@@ -1132,9 +1143,13 @@ struct sys_var_with_base
   Prototypes for helper functions
 */
 
-void set_var_init();
+int set_var_init();
 void set_var_free();
-sys_var *find_sys_var(const char *str, uint length=0);
+int mysql_append_static_vars(const SHOW_VAR *show_vars, uint count);
+SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted);
+int mysql_add_sys_var_chain(sys_var *chain, struct my_option *long_options);
+int mysql_del_sys_var_chain(sys_var *chain);
+sys_var *find_sys_var(THD *thd, const char *str, uint length=0);
 int sql_set_variables(THD *thd, List<set_var_base> *var_list);
 bool not_all_support_one_shot(List<set_var_base> *var_list);
 void fix_delay_key_write(THD *thd, enum_var_type type);
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 15d616bdd4f..131e7c66557 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1596,7 +1596,7 @@ void close_temporary_table(THD *thd, TABLE *table,
 
 void close_temporary(TABLE *table, bool free_share, bool delete_table)
 {
-  handlerton *table_type= table->s->db_type;
+  handlerton *table_type= table->s->db_type();
   DBUG_ENTER("close_temporary");
 
   free_io_cache(table);
@@ -6186,7 +6186,7 @@ my_bool mysql_rm_tmp_tables(void)
           init_tmp_table_share(&share, "", 0, "", filePathCopy);
           if (!open_table_def(thd, &share, 0) &&
               ((handler_file= get_new_handler(&share, thd->mem_root,
-                                              share.db_type))))
+                                              share.db_type()))))
           {
             handler_file->delete_table(filePathCopy);
             delete handler_file;
diff --git a/sql/sql_cache.cc b/sql/sql_cache.cc
index 8c0cb72e1f4..1f6a84462ae 100644
--- a/sql/sql_cache.cc
+++ b/sql/sql_cache.cc
@@ -2384,7 +2384,12 @@ Query_cache::register_tables_from_list(TABLE_LIST *tables_used,
                         tables_used->engine_data))
         DBUG_RETURN(0);
 
-      if (tables_used->table->s->db_type->db_type == DB_TYPE_MRG_MYISAM)
+#ifdef WITH_MYISAMMRG_STORAGE_ENGINE      
+      /*
+        XXX FIXME: Some generic mechanism is required here instead of this
+        MYISAMMRG-specific implementation.
+      */
+      if (tables_used->table->s->db_type()->db_type == DB_TYPE_MRG_MYISAM)
       {
         ha_myisammrg *handler = (ha_myisammrg *) tables_used->table->file;
         MYRG_INFO *file = handler->myrg_info();
@@ -2407,6 +2412,7 @@ Query_cache::register_tables_from_list(TABLE_LIST *tables_used,
             DBUG_RETURN(0);
         }
       }
+#endif
     }
   }
   DBUG_RETURN(n - counter);
@@ -2983,7 +2989,7 @@ static TABLE_COUNTER_TYPE process_and_count_tables(TABLE_LIST *tables_used,
       DBUG_PRINT("qcache", ("table: %s  db:  %s  type: %u",
                             tables_used->table->s->table_name.str,
                             tables_used->table->s->db.str,
-                            tables_used->table->s->db_type->db_type));
+                            tables_used->table->s->db_type()->db_type));
       if (tables_used->derived)
       {
         table_count--;
@@ -3008,12 +3014,18 @@ static TABLE_COUNTER_TYPE process_and_count_tables(TABLE_LIST *tables_used,
                     "other non-cacheable table(s)"));
         DBUG_RETURN(0);
       }
-      if (tables_used->table->s->db_type->db_type == DB_TYPE_MRG_MYISAM)
+#ifdef WITH_MYISAMMRG_STORAGE_ENGINE      
+      /*
+        XXX FIXME: Some generic mechanism is required here instead of this
+        MYISAMMRG-specific implementation.
+      */
+      if (tables_used->table->s->db_type()->db_type == DB_TYPE_MRG_MYISAM)
       {
         ha_myisammrg *handler = (ha_myisammrg *)tables_used->table->file;
         MYRG_INFO *file = handler->myrg_info();
         table_count+= (file->end_table - file->open_tables);
       }
+#endif
     }
   }
   DBUG_RETURN(table_count);
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 039fd71d670..eab6fea9558 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -167,15 +167,15 @@ Open_tables_state::Open_tables_state(ulong version_arg)
   reset_open_tables_state();
 }
 
-my_bool thd_in_lock_tables(const THD *thd)
+int thd_in_lock_tables(const THD *thd)
 {
-  return thd->in_lock_tables;
+  return test(thd->in_lock_tables);
 }
 
 
-my_bool thd_tablespace_op(const THD *thd)
+int thd_tablespace_op(const THD *thd)
 {
-  return thd->tablespace_op;
+  return test(thd->tablespace_op);
 }
 
 
@@ -191,6 +191,82 @@ void **thd_ha_data(const THD *thd, const struct handlerton *hton)
   return (void **) thd->ha_data + hton->slot;
 }
 
+long long thd_test_options(const THD *thd, long long test_options)
+{
+  return thd->options & test_options;
+}
+
+int thd_sql_command(const THD *thd)
+{
+  return (int) thd->lex->sql_command;
+}
+
+
+/*
+  Dumps a text description of a thread, its security context
+  (user, host) and the current query.
+  
+  SYNOPSIS
+    thd_security_context()
+    thd                 current thread context
+    buffer              pointer to preferred result buffer
+    length              length of buffer
+    max_query_len       how many chars of query to copy (0 for all)
+  
+  RETURN VALUES
+    pointer to string
+*/
+char *thd_security_context(THD *thd, char *buffer, int length,
+                           int max_query_len)
+{
+  String str(buffer, length, &my_charset_latin1);
+  const Security_context *sctx= &thd->main_security_ctx;
+  char header[64];
+  int len;
+  
+  len= my_snprintf(header, sizeof(header), 
+                   "MySQL thread id %lu, query id %lu",
+                   thd->thread_id, (ulong) thd->query_id);
+  str.length(0);
+  str.append(header, len);
+  
+  if (sctx->host)
+  {
+    str.append(' ');
+    str.append(sctx->host);
+  }
+
+  if (sctx->ip)
+  {
+    str.append(' ');
+    str.append(sctx->ip);
+  }
+
+  if (sctx->user)
+  {
+    str.append(' ');
+    str.append(sctx->user);
+  }
+
+  if (thd->proc_info)
+  {
+    str.append(' ');
+    str.append(thd->proc_info);
+  }
+
+  if (thd->query)
+  {
+    if (max_query_len < 1)
+      len= thd->query_length;
+    else
+      len= min(thd->query_length, max_query_len);
+    str.append('\n');
+    str.append(thd->query, len);
+  }
+  if (str.c_ptr_safe() == buffer)
+    return buffer;
+  return thd->strmake(str.ptr(), str.length());
+}
 
 /*
   Pass nominal parameters to Statement constructor only to ensure that
@@ -320,6 +396,7 @@ void THD::init(void)
 {
   pthread_mutex_lock(&LOCK_global_system_variables);
   variables= global_system_variables;
+  plugin_thdvar_init(this, false);
   variables.time_format= date_time_format_copy((THD*) 0,
 					       variables.time_format);
   variables.date_format= date_time_format_copy((THD*) 0,
@@ -465,6 +542,7 @@ THD::~THD()
     cleanup();
 
   ha_close_connection(this);
+  plugin_thdvar_cleanup(this);
 
   DBUG_PRINT("info", ("freeing security context"));
   main_security_ctx.destroy();
@@ -1682,7 +1760,7 @@ Statement::Statement(enum enum_state state_arg, ulong id_arg,
   :Query_arena(&main_mem_root, state_arg),
   id(id_arg),
   mark_used_columns(MARK_COLUMNS_READ),
-  lex(&main_lex),
+  main_lex(), lex(&main_lex),
   query(0),
   query_length(0),
   cursor(0)
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 1f5f7aedbb4..08b5c772c8a 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -180,6 +180,20 @@ class Time_zone;
 
 struct system_variables
 {
+  /*
+    How dynamically allocated system variables are handled:
+    
+    The global_system_variables and max_system_variables are "authoritative"
+    They both should have the same 'version' and 'size'.
+    When attempting to access a dynamic variable, if the session version
+    is out of date, then the session version is updated and realloced if
+    neccessary and bytes copied from global to make up for missing data.
+  */ 
+  ulong dynamic_variables_version;
+  char* dynamic_variables_ptr;
+  uint dynamic_variables_head;  /* largest valid variable offset */
+  uint dynamic_variables_size;  /* how many bytes are in use */
+  
   ulonglong myisam_max_extra_sort_file_size;
   ulonglong myisam_max_sort_file_size;
   ulonglong max_heap_table_size;
@@ -245,8 +259,6 @@ struct system_variables
   my_bool new_mode;
   my_bool query_cache_wlock_invalidate;
   my_bool engine_condition_pushdown;
-  my_bool innodb_table_locks;
-  my_bool innodb_support_xa;
   my_bool ndb_force_send;
   my_bool ndb_use_copying_alter_table;
   my_bool ndb_use_exact_count;
@@ -256,7 +268,7 @@ struct system_variables
   my_bool old_alter_table;
   my_bool old_passwords;
 
-  handlerton *table_type;
+  plugin_ref table_plugin;
 
   /* Only charset part of these variables is sensible */
   CHARSET_INFO  *character_set_filesystem;
diff --git a/sql/sql_connect.cc b/sql/sql_connect.cc
index 09ee4962235..41b4c1b8e31 100644
--- a/sql/sql_connect.cc
+++ b/sql/sql_connect.cc
@@ -966,6 +966,7 @@ bool login_connection(THD *thd)
 void end_connection(THD *thd)
 {
   NET *net= &thd->net;
+  plugin_thdvar_cleanup(thd);
   if (thd->user_connect)
     decrease_user_connections(thd->user_connect);
   if (net->error && net->vio != 0 && net->report_error)
@@ -1003,6 +1004,8 @@ void prepare_new_connection_state(THD* thd)
   if (thd->client_capabilities & CLIENT_COMPRESS)
     thd->net.compress=1;				// Use compression
 
+  plugin_thdvar_init(thd, true);
+
   thd->version= refresh_version;
   thd->proc_info= 0;
   thd->command= COM_SLEEP;
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index ea8c0e2d83e..2ce1486e278 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -868,7 +868,7 @@ bool mysql_truncate(THD *thd, TABLE_LIST *table_list, bool dont_send_ok)
   /* If it is a temporary table, close and regenerate it */
   if (!dont_send_ok && (table= find_temporary_table(thd, table_list)))
   {
-    handlerton *table_type= table->s->db_type;
+    handlerton *table_type= table->s->db_type();
     TABLE_SHARE *share= table->s;
     if (!ha_check_storage_engine_flag(table_type, HTON_CAN_RECREATE))
       goto trunc_by_del;
diff --git a/sql/sql_insert.cc b/sql/sql_insert.cc
index 6f4cdbba3dd..f63aaf2d0fc 100644
--- a/sql/sql_insert.cc
+++ b/sql/sql_insert.cc
@@ -3232,7 +3232,7 @@ void select_create::abort()
   {
     table->file->extra(HA_EXTRA_NO_IGNORE_DUP_KEY);
     table->file->extra(HA_EXTRA_WRITE_CANNOT_REPLACE);
-    handlerton *table_type=table->s->db_type;
+    handlerton *table_type=table->s->db_type();
     if (!table->s->tmp_table)
     {
       ulong version= table->s->version;
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index af2929b6268..1c78aada405 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -172,6 +172,7 @@ void lex_start(THD *thd, const uchar *buf, uint length)
   lex->spcont= NULL;
   lex->proc_list.first= 0;
   lex->escape_used= FALSE;
+  lex->query_tables= 0;
   lex->reset_query_tables_list(FALSE);
   lex->expr_allows_subselect= TRUE;
 
@@ -211,6 +212,12 @@ void lex_end(LEX *lex)
     lex->yacc_yyss= 0;
     lex->yacc_yyvs= 0;
   }
+
+  /* release used plugins */
+  plugin_unlock_list(0, (plugin_ref*)lex->plugins.buffer, 
+                     lex->plugins.elements);
+  reset_dynamic(&lex->plugins);
+
   DBUG_VOID_RETURN;
 }
 
@@ -1673,6 +1680,17 @@ void st_select_lex::print_limit(THD *thd, String *str)
 
 void Query_tables_list::reset_query_tables_list(bool init)
 {
+  if (!init && query_tables)
+  {
+    TABLE_LIST *table= query_tables;
+    for (;;)
+    {
+      delete table->view;
+      if (query_tables_last == &table->next_global ||
+          !(table= table->next_global))
+        break;
+    }
+  }
   query_tables= 0;
   query_tables_last= &query_tables;
   query_tables_own_last= 0;
@@ -1727,6 +1745,10 @@ st_lex::st_lex()
   :result(0), yacc_yyss(0), yacc_yyvs(0),
    sql_command(SQLCOM_END)
 {
+  my_init_dynamic_array2(&plugins, sizeof(plugin_ref),
+                         plugins_static_buffer,
+                         INITIAL_LEX_PLUGIN_LIST_SIZE, 
+                         INITIAL_LEX_PLUGIN_LIST_SIZE);
   reset_query_tables_list(TRUE);
 }
 
diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 821af3f946d..415745eb2aa 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -952,6 +952,11 @@ typedef struct st_lex : public Query_tables_list
   XID *xid;
   gptr yacc_yyss,yacc_yyvs;
   THD *thd;
+
+  /* maintain a list of used plugins for this LEX */
+  DYNAMIC_ARRAY plugins;
+  plugin_ref plugins_static_buffer[INITIAL_LEX_PLUGIN_LIST_SIZE];
+  
   CHARSET_INFO *charset, *underscore_charset;
   /* store original leaf_tables for INSERT SELECT and PS/SP */
   TABLE_LIST *leaf_tables_insert;
@@ -1155,6 +1160,8 @@ typedef struct st_lex : public Query_tables_list
   virtual ~st_lex()
   {
     destroy_query_tables_list();
+    plugin_unlock_list(NULL, (plugin_ref *)plugins.buffer, plugins.elements);
+    delete_dynamic(&plugins);
   }
 
   inline void uncacheable(uint8 cause)
diff --git a/sql/sql_partition.cc b/sql/sql_partition.cc
index dbac53ed5f6..cb16a5fbcfd 100644
--- a/sql/sql_partition.cc
+++ b/sql/sql_partition.cc
@@ -784,9 +784,9 @@ static bool handle_list_of_fields(List_iterator<char> it,
     }
     else
     {
-      if (table->s->db_type->partition_flags &&
-          (table->s->db_type->partition_flags() & HA_USE_AUTO_PARTITION) &&
-          (table->s->db_type->partition_flags() & HA_CAN_PARTITION))
+      if (table->s->db_type()->partition_flags &&
+          (table->s->db_type()->partition_flags() & HA_USE_AUTO_PARTITION) &&
+          (table->s->db_type()->partition_flags() & HA_CAN_PARTITION))
       {
         /*
           This engine can handle automatic partitioning and there is no
@@ -1664,8 +1664,8 @@ bool fix_partition_func(THD *thd, TABLE *table,
     goto end;
   if (unlikely(check_primary_key(table)))
     goto end;
-  if (unlikely((!(table->s->db_type->partition_flags &&
-      (table->s->db_type->partition_flags() & HA_CAN_PARTITION_UNIQUE))) &&
+  if (unlikely((!(table->s->db_type()->partition_flags &&
+      (table->s->db_type()->partition_flags() & HA_CAN_PARTITION_UNIQUE))) &&
                check_unique_keys(table)))
     goto end;
   if (unlikely(set_up_partition_bitmap(thd, part_info)))
@@ -1872,7 +1872,7 @@ static int add_keyword_int(File fptr, const char *keyword, longlong num)
 
 static int add_engine(File fptr, handlerton *engine_type)
 {
-  const char *engine_str= hton2plugin[engine_type->slot]->name.str;
+  const char *engine_str= ha_resolve_storage_engine_name(engine_type);
   DBUG_PRINT("info", ("ENGINE: %s", engine_str));
   int err= add_string(fptr, "ENGINE = ");
   return err + add_string(fptr, engine_str);
@@ -2185,8 +2185,8 @@ bool partition_key_modified(TABLE *table, const MY_BITMAP *fields)
 
   if (!part_info)
     DBUG_RETURN(FALSE);
-  if (table->s->db_type->partition_flags &&
-      (table->s->db_type->partition_flags() & HA_CAN_UPDATE_PARTITION_KEY))
+  if (table->s->db_type()->partition_flags &&
+      (table->s->db_type()->partition_flags() & HA_CAN_UPDATE_PARTITION_KEY))
     DBUG_RETURN(FALSE);
   for (fld= part_info->full_part_field_array; *fld; fld++)
     if (bitmap_is_set(fields, (*fld)->field_index))
@@ -4201,8 +4201,8 @@ uint prep_alter_part_table(THD *thd, TABLE *table, ALTER_INFO *alter_info,
         alter_info->no_parts= curr_part_no - new_part_no;
       }
     }
-    if (table->s->db_type->alter_table_flags &&
-        (!(flags= table->s->db_type->alter_table_flags(alter_info->flags))))
+    if (table->s->db_type()->alter_table_flags &&
+        (!(flags= table->s->db_type()->alter_table_flags(alter_info->flags))))
     {
       my_error(ER_PARTITION_FUNCTION_FAILURE, MYF(0));
       DBUG_RETURN(1);
@@ -4948,7 +4948,7 @@ the generated partition syntax in a correct manner.
           create_info->db_type= table->part_info->default_engine_type;
         }
         DBUG_PRINT("info", ("New engine type: %s",
-                   hton2plugin[create_info->db_type->slot]->name.str));
+                   ha_resolve_storage_engine_name(create_info->db_type)));
         thd->work_part_info= NULL;
         *partition_changed= TRUE;
       }
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index e3e24c1f375..06f687e779f 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -15,11 +15,21 @@
 
 #include "mysql_priv.h"
 #include <my_pthread.h>
+#include <my_getopt.h>
 #define REPORT_TO_LOG  1
 #define REPORT_TO_USER 2
 
+#ifdef DBUG_OFF
+#define plugin_ref_to_int(A) A
+#define plugin_int_to_ref(A) A
+#else
+#define plugin_ref_to_int(A) (A ? A[0] : NULL)
+#define plugin_int_to_ref(A) &(A)
+#endif
+
 extern struct st_mysql_plugin *mysqld_builtins[];
 
+char *opt_plugin_load= NULL;
 char *opt_plugin_dir_ptr;
 char opt_plugin_dir[FN_REFLEN];
 /*
@@ -85,25 +95,207 @@ static int cur_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
 static DYNAMIC_ARRAY plugin_dl_array;
 static DYNAMIC_ARRAY plugin_array;
 static HASH plugin_hash[MYSQL_MAX_PLUGIN_TYPE_NUM];
-static rw_lock_t THR_LOCK_plugin;
+/* we are always manipulating ref count, so a rwlock is unneccessary */
+static pthread_mutex_t LOCK_plugin;
 static bool initialized= 0;
+static bool reap_needed= false;
 
 static int plugin_array_version=0;
 
+
+/*
+  write-lock on LOCK_system_variables_hash is required before modifying
+  the following variables/structures
+*/
+static MEM_ROOT plugin_mem_root;
+static uint global_variables_dynamic_size= 0;
+static HASH bookmark_hash;
+
+
+/*
+  hidden part of opaque value passed to variable check functions.
+  Used to provide a object-like structure to non C++ consumers.
+*/
+struct st_item_value_holder : public st_mysql_value
+{
+  Item *item;
+};
+
+
+/*
+  stored in bookmark_hash, this structure is never removed from the
+  hash and is used to mark a single offset for a thd local variable 
+  even if plugins have been uninstalled and reinstalled, repeatedly.
+  This structure is allocated from plugin_mem_root.
+*/
+struct st_bookmark
+{
+  char *name;
+  uint name_len;
+  int offset;
+  uint version;
+};
+
+
+/*
+  skeleton of a plugin variable - portion of structure common to all.
+*/
+struct st_mysql_sys_var
+{
+  MYSQL_PLUGIN_VAR_HEADER;
+};
+
+
+/*
+  sys_var class for access to all plugin variables visible to the user
+*/
+class sys_var_pluginvar: public sys_var
+{
+public:
+  struct st_plugin_int *plugin;
+  struct st_mysql_sys_var *plugin_var;
+
+  static void *operator new(size_t size, MEM_ROOT *mem_root)
+  { return (void*) alloc_root(mem_root, (uint) size); }
+  static void operator delete(void *ptr_arg,size_t size)
+  { TRASH(ptr_arg, size); }
+
+  sys_var_pluginvar(const char *name_arg,
+                    struct st_plugin_int *plugin_arg,
+                    struct st_mysql_sys_var *plugin_var_arg)
+    :sys_var(name_arg), plugin(plugin_arg), plugin_var(plugin_var_arg) {}
+  sys_var_pluginvar *cast_pluginvar() { return this; }
+  bool is_readonly() const { return plugin_var->flags & PLUGIN_VAR_READONLY; }
+  bool check_type(enum_var_type type)
+  { return !(plugin_var->flags & PLUGIN_VAR_THDLOCAL) && type != OPT_GLOBAL; }
+  bool check_update_type(Item_result type);
+  SHOW_TYPE show_type();
+  byte* real_value_ptr(THD *thd, enum_var_type type);
+  TYPELIB* plugin_var_typelib(void);
+  byte* value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
+  bool check(THD *thd, set_var *var);
+  void set_default(THD *thd, enum_var_type type);
+  bool update(THD *thd, set_var *var);
+};
+
+
 /* prototypes */
-my_bool plugin_register_builtin(struct st_mysql_plugin *plugin);
-void plugin_load(void);
+static void plugin_load(MEM_ROOT *tmp_root, int *argc, char **argv);
+static bool plugin_load_list(MEM_ROOT *tmp_root, int *argc, char **argv,
+                             const char *list);
+static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
+                               int *argc, char **argv, my_bool default_enabled);
+static bool register_builtin(struct st_mysql_plugin *plugin, 
+                             struct st_plugin_int *tmp,
+                             struct st_plugin_int **ptr);
+static void cleanup_variables(THD *thd, struct system_variables *vars, 
+                              bool free_memory);
+static void plugin_opt_set_limits(struct my_option *options,
+                                  const struct st_mysql_sys_var *opt);
+#define my_intern_plugin_lock(A,B) intern_plugin_lock(A,B CALLER_INFO)
+#define my_intern_plugin_lock_ci(A,B) intern_plugin_lock(A,B ORIG_CALLER_INFO)
+static plugin_ref intern_plugin_lock(LEX *lex, plugin_ref plugin
+                                     CALLER_INFO_PROTO);
+static void intern_plugin_unlock(LEX *lex, plugin_ref plugin);
+static void reap_plugins(void);
+
+
+/* declared in set_var.cc */
+extern sys_var *intern_find_sys_var(const char *str, uint length, bool no_error);
+
+
+/****************************************************************************
+  Value type thunks, allows the C world to play in the C++ world
+****************************************************************************/
+
+static int item_value_type(struct st_mysql_value *value)
+{
+  switch (((st_item_value_holder*)value)->item->result_type()) {
+  case INT_RESULT:
+    return MYSQL_VALUE_TYPE_INT;
+  case REAL_RESULT:
+    return MYSQL_VALUE_TYPE_REAL;
+  default:
+    return MYSQL_VALUE_TYPE_STRING;  
+  }
+}
+
+static const char *item_val_str(struct st_mysql_value *value, 
+                                char *buffer, int *length)
+{
+  String str(buffer, *length, system_charset_info), *res;
+  if (!(res= ((st_item_value_holder*)value)->item->val_str(&str)))
+    return NULL;
+  *length= res->length();
+  if (res->c_ptr_quick() == buffer)
+    return buffer;
+    
+  /*
+    Lets be nice and create a temporary string since the 
+    buffer was too small
+  */
+  return current_thd->strmake(res->c_ptr_quick(), res->length());
+}
+
+
+static int item_val_int(struct st_mysql_value *value, void *buf, int intsize)
+{
+  Item *item= ((st_item_value_holder*)value)->item;
+  switch (intsize) {
+  case 1:
+    *(char*)buf= item->val_int();
+    break;
+  case 2:
+    *(short*)buf= item->val_int();
+    break;
+  case 4:
+    *(int*)buf= item->val_int();
+    break;
+  case 8:
+    *(longlong*)buf= item->val_int();
+    break;
+  default:
+    return -1;
+  }
+  if (item->is_null())
+    return 1;
+  return 0;
+}
+
+
+static int item_val_real(struct st_mysql_value *value, void *buf, int realsize)
+{
+  Item *item= ((st_item_value_holder*)value)->item;
+  switch (realsize) {
+  case 8:
+    *(double*)buf= item->val_real();
+    break;
+  case 4:
+    *(float*)buf= item->val_real();
+    break;
+  default:
+    return -1;
+  }
+  if (item->is_null())
+    return 1;
+  return 0;
+}
+
+
+/****************************************************************************
+  Plugin support code
+****************************************************************************/
 
 #ifdef HAVE_DLOPEN
 
 static struct st_plugin_dl *plugin_dl_find(const LEX_STRING *dl)
 {
   uint i;
+  struct st_plugin_dl *tmp;
   DBUG_ENTER("plugin_dl_find");
   for (i= 0; i < plugin_dl_array.elements; i++)
   {
-    struct st_plugin_dl *tmp= dynamic_element(&plugin_dl_array, i,
-                                              struct st_plugin_dl *);
+    tmp= dynamic_element(&plugin_dl_array, i, struct st_plugin_dl *);
     if (tmp->ref_count &&
         ! my_strnncoll(files_charset_info,
                        (const uchar *)dl->str, dl->length,
@@ -117,11 +309,11 @@ static struct st_plugin_dl *plugin_dl_find(const LEX_STRING *dl)
 static st_plugin_dl *plugin_dl_insert_or_reuse(struct st_plugin_dl *plugin_dl)
 {
   uint i;
+  struct st_plugin_dl *tmp;
   DBUG_ENTER("plugin_dl_insert_or_reuse");
   for (i= 0; i < plugin_dl_array.elements; i++)
   {
-    struct st_plugin_dl *tmp= dynamic_element(&plugin_dl_array, i,
-                                              struct st_plugin_dl *);
+    tmp= dynamic_element(&plugin_dl_array, i, struct st_plugin_dl *);
     if (! tmp->ref_count)
     {
       memcpy(tmp, plugin_dl, sizeof(struct st_plugin_dl));
@@ -147,6 +339,7 @@ static inline void free_plugin_mem(struct st_plugin_dl *p)
     my_free((gptr)p->plugins, MYF(MY_ALLOW_ZERO_PTR));
 }
 
+
 static st_plugin_dl *plugin_dl_add(const LEX_STRING *dl, int report)
 {
 #ifdef HAVE_DLOPEN
@@ -334,6 +527,9 @@ static void plugin_dl_del(const LEX_STRING *dl)
 #ifdef HAVE_DLOPEN
   uint i;
   DBUG_ENTER("plugin_dl_del");
+
+  safe_mutex_assert_owner(&LOCK_plugin);
+
   for (i= 0; i < plugin_dl_array.elements; i++)
   {
     struct st_plugin_dl *tmp= dynamic_element(&plugin_dl_array, i,
@@ -363,6 +559,9 @@ static struct st_plugin_int *plugin_find_internal(const LEX_STRING *name, int ty
   DBUG_ENTER("plugin_find_internal");
   if (! initialized)
     DBUG_RETURN(0);
+
+  safe_mutex_assert_owner(&LOCK_plugin);
+
   if (type == MYSQL_ANY_PLUGIN)
   {
     for (i= 0; i < MYSQL_MAX_PLUGIN_TYPE_NUM; i++)
@@ -380,33 +579,105 @@ static struct st_plugin_int *plugin_find_internal(const LEX_STRING *name, int ty
 }
 
 
-my_bool plugin_is_ready(const LEX_STRING *name, int type)
+static SHOW_COMP_OPTION plugin_status(const LEX_STRING *name, int type)
 {
-  my_bool rc= FALSE;
+  SHOW_COMP_OPTION rc= SHOW_OPTION_NO;
   struct st_plugin_int *plugin;
   DBUG_ENTER("plugin_is_ready");
-  rw_rdlock(&THR_LOCK_plugin);
-  if ((plugin= plugin_find_internal(name, type)) &&
-      plugin->state == PLUGIN_IS_READY)
-    rc= TRUE;
-  rw_unlock(&THR_LOCK_plugin);
+  pthread_mutex_lock(&LOCK_plugin);
+  if ((plugin= plugin_find_internal(name, type)))
+  {
+    rc= SHOW_OPTION_DISABLED;
+    if (plugin->state == PLUGIN_IS_READY)
+      rc= SHOW_OPTION_YES;
+  }
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(rc);
 }
 
 
-struct st_plugin_int *plugin_lock(const LEX_STRING *name, int type)
+bool plugin_is_ready(const LEX_STRING *name, int type)
 {
-  struct st_plugin_int *rc;
-  DBUG_ENTER("plugin_lock");
-  rw_wrlock(&THR_LOCK_plugin);
-  if ((rc= plugin_find_internal(name, type)))
+  bool rc= FALSE;
+  if (plugin_status(name, type) == SHOW_OPTION_YES)
+    rc= TRUE;
+  return rc;
+}
+
+
+SHOW_COMP_OPTION sys_var_have_plugin::get_option()
+{
+  LEX_STRING plugin_name= { (char *) plugin_name_str, plugin_name_len };
+  return plugin_status(&plugin_name, plugin_type);
+}
+
+
+static plugin_ref intern_plugin_lock(LEX *lex, plugin_ref rc CALLER_INFO_PROTO)
+{
+  st_plugin_int *pi= plugin_ref_to_int(rc);
+  DBUG_ENTER("intern_plugin_lock");
+  
+  safe_mutex_assert_owner(&LOCK_plugin);
+  
+  if (pi->state & (PLUGIN_IS_READY | PLUGIN_IS_UNINITIALIZED))
   {
-    if (rc->state & (PLUGIN_IS_READY | PLUGIN_IS_UNINITIALIZED))
-      rc->ref_count++;
-    else
-      rc= 0;
+    plugin_ref plugin;
+#ifdef DBUG_OFF
+    /* built-in plugins don't need ref counting */
+    if (!pi->plugin_dl)
+      DBUG_RETURN(pi);
+
+    plugin= pi;
+#else
+    if (!(plugin= (plugin_ref) my_malloc_ci(sizeof(pi), MYF(MY_WME))))
+      DBUG_RETURN(NULL);
+    //if (0x4620a20L == (long) plugin)
+    if (0x4656b10L == (long) plugin)
+    {
+      DBUG_PRINT("debug",("trap"));
+    }
+
+    *plugin= pi;
+#endif
+    pi->ref_count++;
+    DBUG_PRINT("info",("thd: 0x%lx, plugin: \"%s\", ref_count: %d",
+                       (long) current_thd, pi->name.str, pi->ref_count));
+
+    if (lex)
+      insert_dynamic(&lex->plugins, (gptr)&plugin);
+    DBUG_RETURN(plugin);
   }
-  rw_unlock(&THR_LOCK_plugin);
+  DBUG_RETURN(NULL);
+}
+
+
+plugin_ref plugin_lock(THD *thd, plugin_ref *ptr CALLER_INFO_PROTO)
+{
+  LEX *lex= NULL;
+  plugin_ref rc;
+  DBUG_ENTER("plugin_lock");
+  if (thd)
+    lex= !thd->lex ? &thd->main_lex : thd->lex;
+  pthread_mutex_lock(&LOCK_plugin);
+  rc= my_intern_plugin_lock_ci(lex, *ptr);
+  pthread_mutex_unlock(&LOCK_plugin);
+  DBUG_RETURN(rc);
+}
+
+
+plugin_ref plugin_lock_by_name(THD *thd, const LEX_STRING *name, int type
+                               CALLER_INFO_PROTO)
+{
+  LEX *lex= NULL;
+  plugin_ref rc= NULL;
+  st_plugin_int *plugin;
+  DBUG_ENTER("plugin_lock");
+  if (thd)
+    lex= !thd->lex ? &thd->main_lex : thd->lex;
+  pthread_mutex_lock(&LOCK_plugin);
+  if ((plugin= plugin_find_internal(name, type)))
+    rc= my_intern_plugin_lock_ci(lex, plugin_int_to_ref(plugin));
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(rc);
 }
 
@@ -431,7 +702,14 @@ static st_plugin_int *plugin_insert_or_reuse(struct st_plugin_int *plugin)
                               struct st_plugin_int *));
 }
 
-static my_bool plugin_add(const LEX_STRING *name, const LEX_STRING *dl, int report)
+
+/*
+  NOTE
+    Requires that a write-lock is held on LOCK_system_variables_hash
+*/
+static bool plugin_add(MEM_ROOT *tmp_root,
+                       const LEX_STRING *name, const LEX_STRING *dl, 
+                       int *argc, char **argv, int report)
 {
   struct st_plugin_int tmp;
   struct st_mysql_plugin *plugin;
@@ -477,14 +755,26 @@ static my_bool plugin_add(const LEX_STRING *name, const LEX_STRING *dl, int repo
       tmp.name.length= name_len;
       tmp.ref_count= 0;
       tmp.state= PLUGIN_IS_UNINITIALIZED;
-      if (! (tmp_plugin_ptr= plugin_insert_or_reuse(&tmp)))
-        goto err;
-      plugin_array_version++;
-      if (my_hash_insert(&plugin_hash[plugin->type], (byte*)tmp_plugin_ptr))
+      
+      if (!test_plugin_options(tmp_root, &tmp, argc, argv, true))
       {
-        tmp_plugin_ptr->state= PLUGIN_IS_FREED;
-        goto err;
+        if ((tmp_plugin_ptr= plugin_insert_or_reuse(&tmp)))
+        {
+          plugin_array_version++;
+          if (!my_hash_insert(&plugin_hash[plugin->type], (byte*)tmp_plugin_ptr))
+          {
+            init_alloc_root(&tmp_plugin_ptr->mem_root, 4096, 4096);
+            DBUG_RETURN(FALSE);
+          }
+          tmp_plugin_ptr->state= PLUGIN_IS_FREED;
+          goto err;
+        }
+        mysql_del_sys_var_chain(tmp.system_vars);
+        plugin_dl_del(dl);
+        DBUG_RETURN(TRUE);
       }
+      /* plugin was disabled */
+      plugin_dl_del(dl);
       DBUG_RETURN(FALSE);
     }
   }
@@ -498,8 +788,14 @@ err:
 }
 
 
-void plugin_deinitialize(struct st_plugin_int *plugin)
+static void plugin_deinitialize(struct st_plugin_int *plugin, bool ref_check)
 {
+  /*
+    we don't want to hold the LOCK_plugin mutex as it may cause
+    deinitialization to deadlock if plugins have worker threads
+    with plugin locks
+  */
+  safe_mutex_assert_not_owner(&LOCK_plugin);  
 
   if (plugin->plugin->status_vars)
   {
@@ -539,16 +835,29 @@ void plugin_deinitialize(struct st_plugin_int *plugin)
     }
   }
   plugin->state= PLUGIN_IS_UNINITIALIZED;
+
+  /*
+    We do the check here because NDB has a worker THD which doesn't
+    exit until NDB is shut down.
+  */
+  if (ref_check && plugin->ref_count)
+    sql_print_error("Plugin '%s' has ref_count=%d after deinitialization.",
+                    plugin->name.str, plugin->ref_count);
 }
 
 
 static void plugin_del(struct st_plugin_int *plugin)
 {
   DBUG_ENTER("plugin_del(plugin)");
+  safe_mutex_assert_owner(&LOCK_plugin);
   hash_delete(&plugin_hash[plugin->plugin->type], (byte*)plugin);
   plugin_dl_del(&plugin->plugin_dl->dl);
   plugin->state= PLUGIN_IS_FREED;
   plugin_array_version++;
+  rw_wrlock(&LOCK_system_variables_hash);
+  mysql_del_sys_var_chain(plugin->system_vars);
+  rw_unlock(&LOCK_system_variables_hash);
+  free_root(&plugin->mem_root, MYF(0));
   DBUG_VOID_RETURN;
 }
 
@@ -565,18 +874,120 @@ static void plugin_del(const LEX_STRING *name)
 
 #endif
 
-void plugin_unlock(struct st_plugin_int *plugin)
+static void reap_plugins(void)
 {
-  DBUG_ENTER("plugin_unlock");
-  rw_wrlock(&THR_LOCK_plugin);
-  DBUG_ASSERT(plugin && plugin->ref_count);
-  plugin->ref_count--;
-  if (plugin->state == PLUGIN_IS_DELETED && ! plugin->ref_count)
+  uint count, idx;
+  struct st_plugin_int *plugin, **reap, **list;
+  
+  safe_mutex_assert_owner(&LOCK_plugin);
+
+  if (!reap_needed)
+    return;
+    
+  reap_needed= false;
+  count= plugin_array.elements;
+  reap= (struct st_plugin_int **)my_alloca(sizeof(plugin)*(count+1));
+  *(reap++)= NULL;
+  
+  for (idx= 0; idx < count; idx++)
   {
-    plugin_deinitialize(plugin);
+    plugin= dynamic_element(&plugin_array, idx, struct st_plugin_int *);
+    if (plugin->state == PLUGIN_IS_DELETED && !plugin->ref_count)
+    {
+      /* change the status flag to prevent reaping by another thread */
+      plugin->state= PLUGIN_IS_DYING;
+      *(reap++)= plugin;
+    }
+  }
+  
+  pthread_mutex_unlock(&LOCK_plugin);
+
+  list= reap;
+  while ((plugin= *(--list)))
+    plugin_deinitialize(plugin, true);
+  
+  pthread_mutex_lock(&LOCK_plugin);
+  
+  while ((plugin= *(--reap)))
     plugin_del(plugin);
+  
+  my_afree(reap);
+}
+
+static void intern_plugin_unlock(LEX *lex, plugin_ref plugin)
+{
+  int i;
+  st_plugin_int *pi;
+  DBUG_ENTER("intern_plugin_unlock");
+
+  safe_mutex_assert_owner(&LOCK_plugin);
+
+  if (!plugin)
+    DBUG_VOID_RETURN;
+
+  pi= plugin_ref_to_int(plugin);
+
+#ifdef DBUG_OFF
+  if (!pi->plugin_dl)
+    DBUG_VOID_RETURN;
+#else
+  *(long *) plugin= -1; /* salt the ground, we're debugging */
+  my_free((gptr) plugin, MYF(MY_WME));
+#endif
+
+  DBUG_PRINT("info",("unlocking plugin, name= %s, ref_count= %d",
+                     pi->name.str, pi->ref_count));
+  if (lex)
+  {
+    /* remove one instance of this plugin from the use list */
+    for (i= lex->plugins.elements - 1; i >= 0; i--)
+      if (plugin == *dynamic_element(&lex->plugins, i, plugin_ref*))
+      {
+        delete_dynamic_element(&lex->plugins, i);
+        break;
+      }
+    DBUG_ASSERT(i >= 0);    
   }
-  rw_unlock(&THR_LOCK_plugin);
+
+  DBUG_ASSERT(pi->ref_count);
+  pi->ref_count--;
+
+  if (pi->state == PLUGIN_IS_DELETED && !pi->ref_count)
+    reap_needed= true;
+
+  DBUG_VOID_RETURN;
+}
+
+
+void plugin_unlock(THD *thd, plugin_ref plugin)
+{
+  LEX *lex= thd ? ( !thd->lex ? &thd->main_lex : thd->lex) : NULL;
+  DBUG_ENTER("plugin_unlock");
+  if (!plugin)
+    DBUG_VOID_RETURN;
+#ifdef DBUG_OFF
+  /* built-in plugins don't need ref counting */
+  if (!plugin_dlib(plugin))
+    DBUG_VOID_RETURN;
+#endif
+  pthread_mutex_lock(&LOCK_plugin);
+  intern_plugin_unlock(lex, plugin);
+  reap_plugins();
+  pthread_mutex_unlock(&LOCK_plugin);
+  DBUG_VOID_RETURN;
+}
+
+
+void plugin_unlock_list(THD *thd, plugin_ref *list, uint count)
+{
+  LEX *lex= thd ? ( !thd->lex ? &thd->main_lex : thd->lex) : NULL;
+  DBUG_ENTER("plugin_unlock_list");
+  DBUG_ASSERT(list);
+  pthread_mutex_lock(&LOCK_plugin);
+  while (count--)
+    intern_plugin_unlock(lex, *list++);
+  reap_plugins();
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_VOID_RETURN;
 }
 
@@ -585,6 +996,8 @@ static int plugin_initialize(struct st_plugin_int *plugin)
 {
   DBUG_ENTER("plugin_initialize");
 
+  safe_mutex_assert_owner(&LOCK_plugin);  
+
   if (plugin_type_initialize[plugin->plugin->type])
   {
     if ((*plugin_type_initialize[plugin->plugin->type])(plugin))
@@ -626,12 +1039,29 @@ static int plugin_initialize(struct st_plugin_int *plugin)
     add_status_vars(plugin->plugin->status_vars); // add_status_vars makes a copy
 #endif /* FIX_LATER */
   }
+  
+  /*
+    set the plugin attribute of plugin's sys vars so they are pointing
+    to the active plugin
+  */
+  if (plugin->system_vars)
+  {
+    sys_var_pluginvar *var= plugin->system_vars->cast_pluginvar();
+    for (;;)
+    {
+      var->plugin= plugin;
+      if (!var->next)
+        break;
+      var= var->next->cast_pluginvar();
+    }
+  }
 
   DBUG_RETURN(0);
 err:
   DBUG_RETURN(1);
 }
 
+
 static byte *get_hash_key(const byte *buff, uint *length,
                    my_bool not_used __attribute__((unused)))
 {
@@ -641,6 +1071,15 @@ static byte *get_hash_key(const byte *buff, uint *length,
 }
 
 
+static byte *get_bookmark_hash_key(const byte *buff, uint *length,
+                   my_bool not_used __attribute__((unused)))
+{
+  struct st_bookmark *var= (st_bookmark *)buff;
+  *length= var->name_len + 1;
+  return (byte*) var->name;
+}
+
+
 /*
   The logic is that we first load and initialize all compiled in plugins.
   From there we load up the dynamic types (assuming we have not been told to
@@ -648,17 +1087,28 @@ static byte *get_hash_key(const byte *buff, uint *length,
 
   Finally we inializie everything, aka the dynamic that have yet to initialize.
 */
-int plugin_init(int skip_dynamic_loading)
+int plugin_init(int *argc, char **argv, int flags)
 {
   uint i;
+  bool def_enabled, is_myisam;
   struct st_mysql_plugin **builtins;
   struct st_mysql_plugin *plugin;
+  struct st_plugin_int tmp, *plugin_ptr, **reap;
+  MEM_ROOT tmp_root;
   DBUG_ENTER("plugin_init");
 
   if (initialized)
     DBUG_RETURN(0);
 
-  my_rwlock_init(&THR_LOCK_plugin, NULL);
+  init_alloc_root(&plugin_mem_root, 4096, 4096);
+  init_alloc_root(&tmp_root, 4096, 4096);
+
+  if (hash_init(&bookmark_hash, &my_charset_bin, 16, 0, 0,
+                  get_bookmark_hash_key, NULL, HASH_UNIQUE))
+      goto err;
+  
+
+  pthread_mutex_init(&LOCK_plugin, MY_MUTEX_INIT_FAST);
 
   if (my_init_dynamic_array(&plugin_dl_array,
                             sizeof(struct st_plugin_dl),16,16) ||
@@ -669,10 +1119,14 @@ int plugin_init(int skip_dynamic_loading)
   for (i= 0; i < MYSQL_MAX_PLUGIN_TYPE_NUM; i++)
   {
     if (hash_init(&plugin_hash[i], system_charset_info, 16, 0, 0,
-                  get_hash_key, NULL, 0))
+                  get_hash_key, NULL, HASH_UNIQUE))
       goto err;
   }
 
+  pthread_mutex_lock(&LOCK_plugin);
+
+  initialized= 1;
+
   /*
     First we register builtin plugins
   */
@@ -680,83 +1134,179 @@ int plugin_init(int skip_dynamic_loading)
   {
     for (plugin= *builtins; plugin->info; plugin++)
     {
-//      if (!(strcmp(plugin->name, "MyISAM")))
+      /* by default, only ndbcluster is disabled */
+      def_enabled= 
+        my_strcasecmp(&my_charset_latin1, plugin->name, "NDBCLUSTER") != 0;
+      bzero(&tmp, sizeof(tmp));
+      tmp.plugin= plugin;
+
+      free_root(&tmp_root, MYF(MY_MARK_BLOCKS_FREE));
+      if (test_plugin_options(&tmp_root, &tmp, argc, argv, def_enabled))
+        continue;
+        
+      if (register_builtin(plugin, &tmp, &plugin_ptr))
+        goto err_unlock;
+
+      /* only initialize MyISAM and CSV at this stage */
+      if (!(is_myisam= 
+            !my_strcasecmp(&my_charset_latin1, plugin->name, "MyISAM")) &&
+          my_strcasecmp(&my_charset_latin1, plugin->name, "CSV"))
+        continue;
+
+      if (plugin_initialize(plugin_ptr))
+        goto err_unlock;
+
+      /*
+        initialize the global default storage engine so that it may 
+        not be null in any child thread.
+      */
+      if (is_myisam)
       {
-        if (plugin_register_builtin(plugin))
-          goto err;
-        struct st_plugin_int *tmp= dynamic_element(&plugin_array,
-                                                   plugin_array.elements-1,
-                                                   struct st_plugin_int *);
-        if (plugin_initialize(tmp))
-          goto err;
+        DBUG_ASSERT(!global_system_variables.table_plugin);
+        global_system_variables.table_plugin= (plugin_ref)
+                my_malloc(sizeof(plugin_ptr), MYF(MY_WME | MY_FAE));
+        global_system_variables.table_plugin[0]= plugin_ptr;
+        plugin_ptr->ref_count++;
+        DBUG_ASSERT(plugin_ptr->ref_count == 1);
       }
     }
   }
+  
+  /* should now be set to MyISAM storage engine */
+  DBUG_ASSERT(global_system_variables.table_plugin);
+  
+  pthread_mutex_unlock(&LOCK_plugin);
 
   /* Register all dynamic plugins */
-  if (!skip_dynamic_loading)
-    plugin_load();
+  if (!(flags & PLUGIN_INIT_SKIP_DYNAMIC_LOADING))
+  {
+    if (opt_plugin_load &&
+        plugin_load_list(&tmp_root, argc, argv, opt_plugin_load))
+      goto err;
+    if (!(flags & PLUGIN_INIT_SKIP_PLUGIN_TABLE))
+      plugin_load(&tmp_root, argc, argv);
+  }
 
-  initialized= 1;
+  if (flags & PLUGIN_INIT_SKIP_INITIALIZATION)
+    goto end;
 
   /*
     Now we initialize all remaining plugins
   */
+  pthread_mutex_lock(&LOCK_plugin);
+  reap= (st_plugin_int **) my_alloca((plugin_array.elements+1) * sizeof(void*));
+  *(reap++)= NULL;
+
   for (i= 0; i < plugin_array.elements; i++)
   {
-    struct st_plugin_int *tmp= dynamic_element(&plugin_array, i,
-                                               struct st_plugin_int *);
-    if (tmp->state == PLUGIN_IS_UNINITIALIZED)
+    plugin_ptr= dynamic_element(&plugin_array, i, struct st_plugin_int *);
+    if (plugin_ptr->state == PLUGIN_IS_UNINITIALIZED)
     {
-      if (plugin_initialize(tmp))
+      if (plugin_initialize(plugin_ptr))
       {
-        plugin_deinitialize(tmp);
-        plugin_del(tmp);
+        plugin_ptr->state= PLUGIN_IS_DYING;
+        *(reap++)= plugin_ptr;
       }
     }
   }
 
+  /*
+    Check if any plugins have to be reaped
+  */  
+  while ((plugin_ptr= *(--reap)))
+  {
+    pthread_mutex_unlock(&LOCK_plugin);
+    plugin_deinitialize(plugin_ptr, true);
+    pthread_mutex_lock(&LOCK_plugin);
+    plugin_del(plugin_ptr);
+  }
+
+  pthread_mutex_unlock(&LOCK_plugin);
+  my_afree(reap);
+
+end:
+  free_root(&tmp_root, MYF(0));
   DBUG_RETURN(0);
 
+err_unlock:
+  pthread_mutex_unlock(&LOCK_plugin);
 err:
+  free_root(&tmp_root, MYF(0));
   DBUG_RETURN(1);
 }
 
 
-my_bool plugin_register_builtin(struct st_mysql_plugin *plugin)
+static bool register_builtin(struct st_mysql_plugin *plugin, 
+                             struct st_plugin_int *tmp,
+                             struct st_plugin_int **ptr)
 {
-  struct st_plugin_int tmp;
   DBUG_ENTER("plugin_register_builtin");
 
-  tmp.plugin= plugin;
-  tmp.name.str= (char *)plugin->name;
-  tmp.name.length= strlen(plugin->name);
-  tmp.state= PLUGIN_IS_UNINITIALIZED;
-
-  /* Cannot be unloaded */
-  tmp.ref_count= 1;
-  tmp.plugin_dl= 0;
+  tmp->plugin= plugin;
+  tmp->name.str= (char *)plugin->name;
+  tmp->name.length= strlen(plugin->name);
+  tmp->state= PLUGIN_IS_UNINITIALIZED;
+  tmp->ref_count= 0;
+  tmp->plugin_dl= 0;
 
-  if (insert_dynamic(&plugin_array, (gptr)&tmp))
+  if (insert_dynamic(&plugin_array, (gptr)tmp))
     DBUG_RETURN(1);
 
-  if (my_hash_insert(&plugin_hash[plugin->type],
-                     (byte*)dynamic_element(&plugin_array,
-                                            plugin_array.elements - 1,
-                                            struct st_plugin_int *)))
+  *ptr= dynamic_element(&plugin_array, plugin_array.elements - 1,
+                        struct st_plugin_int *);
+
+  if (my_hash_insert(&plugin_hash[plugin->type],(byte*) *ptr))
     DBUG_RETURN(1);
 
   DBUG_RETURN(0);
 }
 
 
-void plugin_load(void)
+/*
+  Register a plugin at run time. (note, this doesn't initialize a plugin)
+
+  SYNOPSIS
+    plugin_register_builtin()
+    thd         current thread (used to store scratch data in mem_root)
+    plugin      static plugin to install
+
+  RETURN
+    false - plugin registered successfully
+*/
+bool plugin_register_builtin(THD *thd, struct st_mysql_plugin *plugin)
+{
+  struct st_plugin_int tmp, *ptr;
+  bool result= true;
+  int dummy_argc= 0;
+  DBUG_ENTER("plugin_register_builtin");
+
+  bzero(&tmp, sizeof(tmp));
+  tmp.plugin= plugin;
+
+  rw_wrlock(&LOCK_system_variables_hash);
+
+  if (test_plugin_options(thd->mem_root, &tmp, &dummy_argc, NULL, true))
+    goto end;
+
+  if ((result= register_builtin(plugin, &tmp, &ptr)))
+    mysql_del_sys_var_chain(tmp.system_vars);
+
+end:
+  rw_unlock(&LOCK_system_variables_hash);
+
+  DBUG_RETURN(result);;
+}
+
+
+/*
+  called only by plugin_init()
+*/
+static void plugin_load(MEM_ROOT *tmp_root, int *argc, char **argv)
 {
   TABLE_LIST tables;
   TABLE *table;
   READ_RECORD read_record_info;
   int error;
-  MEM_ROOT mem;
   THD *new_thd;
   DBUG_ENTER("plugin_load");
 
@@ -766,7 +1316,6 @@ void plugin_load(void)
     delete new_thd;
     DBUG_VOID_RETURN;
   }
-  init_sql_alloc(&mem, 1024, 0);
   new_thd->thread_stack= (char*) &tables;
   new_thd->store_globals();
   new_thd->db= my_strdup("mysql", MYF(0));
@@ -788,13 +1337,14 @@ void plugin_load(void)
   {
     DBUG_PRINT("info", ("init plugin record"));
     String str_name, str_dl;
-    get_field(&mem, table->field[0], &str_name);
-    get_field(&mem, table->field[1], &str_dl);
+    get_field(tmp_root, table->field[0], &str_name);
+    get_field(tmp_root, table->field[1], &str_dl);
     
     LEX_STRING name= {(char *)str_name.ptr(), str_name.length()};
     LEX_STRING dl= {(char *)str_dl.ptr(), str_dl.length()};
 
-    if (plugin_add(&name, &dl, REPORT_TO_LOG))
+    free_root(tmp_root, MYF(MY_MARK_BLOCKS_FREE));
+    if (plugin_add(tmp_root, &name, &dl, argc, argv, REPORT_TO_LOG))
       sql_print_warning("Couldn't load plugin named '%s' with soname '%s'.",
                         str_name.c_ptr(), str_dl.c_ptr());
   }
@@ -803,7 +1353,6 @@ void plugin_load(void)
   end_read_record(&read_record_info);
   new_thd->version--; // Force close to free memory
 end:
-  free_root(&mem, MYF(0));
   close_thread_tables(new_thd);
   delete new_thd;
   /* Remember that we don't have a THD */
@@ -812,46 +1361,195 @@ end:
 }
 
 
+/*
+  called only by plugin_init()
+*/
+static bool plugin_load_list(MEM_ROOT *tmp_root, int *argc, char **argv,
+                             const char *list)
+{
+  char buffer[FN_REFLEN];
+  LEX_STRING name= {buffer, 0}, dl= {NULL, 0}, *str= &name;
+  struct st_plugin_dl *plugin_dl;
+  struct st_mysql_plugin *plugin;
+  char *p= buffer;
+  DBUG_ENTER("plugin_load_list");
+  while (list)
+  {
+    if (p == buffer + sizeof(buffer) - 1)
+      break;
+    switch ((*(p++)= *(list++))) {
+    case '\0':
+      list= NULL; /* terminate the loop */
+      /* fall through */
+#ifndef __WIN__
+    case ':':     /* can't use this as delimiter as it may be drive letter */
+#endif
+    case ';':
+      name.str[name.length]= '\0';
+      if (str != &dl)  // load all plugins in named module
+      {
+        dl= name;
+        if ((plugin_dl= plugin_dl_add(&dl, REPORT_TO_LOG)))
+        {
+          for (plugin= plugin_dl->plugins; plugin->info; plugin++)
+          {
+            name.str= (char *) plugin->name;
+            name.length= strlen(name.str);
+            
+            free_root(tmp_root, MYF(MY_MARK_BLOCKS_FREE));
+            if (plugin_add(tmp_root, &name, &dl, argc, argv, REPORT_TO_LOG))
+              goto error;
+          }
+          plugin_dl_del(&dl); // reduce ref count
+        }
+      }
+      else
+      {
+        free_root(tmp_root, MYF(MY_MARK_BLOCKS_FREE));
+        if (plugin_add(tmp_root, &name, &dl, argc, argv, REPORT_TO_LOG))
+          goto error;
+      }
+      name.length= dl.length= 0;
+      dl.str= NULL; name.str= p= buffer;
+      str= &name;
+      continue;
+    case '=':
+    case '#':
+      if (str == &name)
+      {
+        str= &dl;
+        str->str= p;
+        continue;
+      }
+    default:
+      str->length++;
+      continue;
+    }
+  }
+  DBUG_RETURN(FALSE);
+error:
+  sql_print_error("Couldn't load plugin named '%s' with soname '%s'.",
+                  name.str, dl.str);
+  DBUG_RETURN(TRUE);
+}
+
+
 void plugin_shutdown(void)
 {
-  uint i;
+  uint i, count= plugin_array.elements;
+  struct st_plugin_int **plugins, *plugin;
+  struct st_plugin_dl **dl;
   DBUG_ENTER("plugin_shutdown");
-
-  /*
-    We loop through all plugins and call deinit() if they have one.
-  */
-  for (i= 0; i < plugin_array.elements; i++)
+  
+  if (initialized)
   {
-    struct st_plugin_int *tmp= dynamic_element(&plugin_array, i,
-                                               struct st_plugin_int *);
-    plugin_deinitialize(tmp);
+    pthread_mutex_lock(&LOCK_plugin);
+
+    cleanup_variables(NULL, &global_system_variables, false);
+    cleanup_variables(NULL, &max_system_variables, false);
+
+    reap_needed= true;
+    
+    /*
+      We want to shut down plugins in a reasonable order, this will
+      become important when we have plugins which depend upon each other.
+      Circular references cannot be reaped so they are forced afterwards.
+      TODO: Have an additional step here to notify all active plugins that
+      shutdown is requested to allow plugins to deinitialize in parallel.
+    */
+    while (reap_needed && (count= plugin_array.elements))
+    {
+      for (i= 0; i < count; i++)
+      {
+        plugin= dynamic_element(&plugin_array, i, struct st_plugin_int *);
+        if (plugin->state == PLUGIN_IS_READY)
+        {
+          plugin->state= PLUGIN_IS_DELETED;
+          reap_needed= true;
+        }
+      }
+      reap_plugins();
+    }
+    
+    plugins= (struct st_plugin_int **) my_alloca(sizeof(void*) * (count+1));
+
+    /*
+      If we have any plugins which did not die cleanly, we force shutdown
+    */
+    for (i= 0; i < count; i++)
+    {
+      plugins[i]= dynamic_element(&plugin_array, i, struct st_plugin_int *);
+      /* change the state to ensure no reaping races */
+      if (plugins[i]->state == PLUGIN_IS_DELETED)
+        plugins[i]->state= PLUGIN_IS_DYING;
+    }
+    pthread_mutex_unlock(&LOCK_plugin);
+    
+    /*
+      We loop through all plugins and call deinit() if they have one.
+    */
+    for (i= 0; i < count; i++)
+      if (!(plugins[i]->state & (PLUGIN_IS_UNINITIALIZED | PLUGIN_IS_FREED)))
+      {
+        sql_print_information("Plugin '%s' will be forced to shutdown", 
+                              plugins[i]->name.str);
+        plugin_deinitialize(plugins[i], false);
+      }
+
+    pthread_mutex_lock(&LOCK_plugin);
+    
+    /*
+      We defer checking ref_counts until after all plugins are deinitialized
+      as some may have worker threads holding on to plugin references.
+    */
+    for (i= 0; i < count; i++)
+      if (plugins[i]->ref_count)
+        sql_print_error("Plugin '%s' has ref_count=%d after shutdown.",
+                        plugins[i]->name.str, plugins[i]->ref_count);
+
+    for (i= 0; i < count; i++)
+      if (plugins[i]->state & PLUGIN_IS_UNINITIALIZED)
+        plugin_del(plugins[i]);
+
+    cleanup_variables(NULL, &global_system_variables, true);
+    cleanup_variables(NULL, &max_system_variables, true);
+
+    initialized= 0;
+    pthread_mutex_unlock(&LOCK_plugin);
+    pthread_mutex_destroy(&LOCK_plugin);
 
   }
+  my_afree(plugins);
 
+  /* Dispose of the memory */
+  
   for (i= 0; i < MYSQL_MAX_PLUGIN_TYPE_NUM; i++)
     hash_free(&plugin_hash[i]);
   delete_dynamic(&plugin_array);
+
+  count= plugin_dl_array.elements;
+  dl= (struct st_plugin_dl **)my_alloca(sizeof(void*) * count);
+  for (i= 0; i < count; i++)
+    dl[i]= dynamic_element(&plugin_dl_array, i, struct st_plugin_dl *);
   for (i= 0; i < plugin_dl_array.elements; i++)
-  {
-    struct st_plugin_dl *tmp= dynamic_element(&plugin_dl_array, i,
-                                              struct st_plugin_dl *);
-    free_plugin_mem(tmp);
-  }
+    free_plugin_mem(dl[i]);
+  my_afree(dl);
   delete_dynamic(&plugin_dl_array);
-  if (initialized)
-  {
-    initialized= 0;
-    rwlock_destroy(&THR_LOCK_plugin);
-  }
+  
+  hash_free(&bookmark_hash);
+  free_root(&plugin_mem_root, MYF(0));
+  
+  global_variables_dynamic_size= 0;
+
   DBUG_VOID_RETURN;
 }
 
 
-my_bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl)
+bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl)
 {
   TABLE_LIST tables;
   TABLE *table;
-  int error;
+  int error, argc=0;
   struct st_plugin_int *tmp;
   DBUG_ENTER("mysql_install_plugin");
 
@@ -861,14 +1559,17 @@ my_bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING
   if (check_table_access(thd, INSERT_ACL, &tables, 0))
     DBUG_RETURN(TRUE);
 
-  /* need to open before acquiring THR_LOCK_plugin or it will deadlock */
+  /* need to open before acquiring LOCK_plugin or it will deadlock */
   if (! (table = open_ltable(thd, &tables, TL_WRITE)))
     DBUG_RETURN(TRUE);
 
-  rw_wrlock(&THR_LOCK_plugin);
-  if (plugin_add(name, dl, REPORT_TO_USER))
-    goto err;
-  tmp= plugin_find_internal(name, MYSQL_ANY_PLUGIN);
+  pthread_mutex_lock(&LOCK_plugin);
+  rw_wrlock(&LOCK_system_variables_hash);
+  error= plugin_add(thd->mem_root, name, dl, &argc, NULL, REPORT_TO_USER);
+  rw_unlock(&LOCK_system_variables_hash);
+
+  if (error || !(tmp= plugin_find_internal(name, MYSQL_ANY_PLUGIN)))
+    goto err;  
 
   if (plugin_initialize(tmp))
   {
@@ -888,18 +1589,19 @@ my_bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING
     goto deinit;
   }
 
-  rw_unlock(&THR_LOCK_plugin);
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(FALSE);
 deinit:
-  plugin_deinitialize(tmp);
-  plugin_del(tmp);
+  tmp->state= PLUGIN_IS_DELETED;
+  reap_needed= true;
+  reap_plugins();
 err:
-  rw_unlock(&THR_LOCK_plugin);
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(TRUE);
 }
 
 
-my_bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
+bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
 {
   TABLE *table;
   TABLE_LIST tables;
@@ -910,11 +1612,11 @@ my_bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
   tables.db= (char *)"mysql";
   tables.table_name= tables.alias= (char *)"plugin";
 
-  /* need to open before acquiring THR_LOCK_plugin or it will deadlock */
+  /* need to open before acquiring LOCK_plugin or it will deadlock */
   if (! (table= open_ltable(thd, &tables, TL_WRITE)))
     DBUG_RETURN(TRUE);
 
-  rw_wrlock(&THR_LOCK_plugin);
+  pthread_mutex_lock(&LOCK_plugin);
   if (!(plugin= plugin_find_internal(name, MYSQL_ANY_PLUGIN)))
   {
     my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "PLUGIN", name->str);
@@ -928,17 +1630,14 @@ my_bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
     goto err;
   }
 
+  plugin->state= PLUGIN_IS_DELETED;
   if (plugin->ref_count)
-  {
     push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN, 0,
                  "Plugin is busy and will be uninstalled on shutdown");
-    plugin->state= PLUGIN_IS_DELETED;
-  }
   else
-  {
-    plugin_deinitialize(plugin);
-    plugin_del(plugin);
-  }
+    reap_needed= true;
+  reap_plugins();
+  pthread_mutex_unlock(&LOCK_plugin);
 
   table->use_all_columns();
   table->field[0]->store(name->str, name->length, system_charset_info);
@@ -951,17 +1650,17 @@ my_bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
     if ((error= table->file->ha_delete_row(table->record[0])))
     {
       table->file->print_error(error, MYF(0));
-      goto err;
+      DBUG_RETURN(TRUE);
     }
   }
-  rw_unlock(&THR_LOCK_plugin);
   DBUG_RETURN(FALSE);
 err:
-  rw_unlock(&THR_LOCK_plugin);
+  pthread_mutex_unlock(&LOCK_plugin);
   DBUG_RETURN(TRUE);
 }
 
-my_bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
+
+bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
                        int type, uint state_mask, void *arg)
 {
   uint idx, total;
@@ -969,16 +1668,19 @@ my_bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
   int version=plugin_array_version;
   DBUG_ENTER("plugin_foreach_with_mask");
 
+  if (!initialized)
+    DBUG_RETURN(FALSE);
+
   state_mask= ~state_mask; // do it only once
 
-  rw_rdlock(&THR_LOCK_plugin);
+  pthread_mutex_lock(&LOCK_plugin);
   total= type == MYSQL_ANY_PLUGIN ? plugin_array.elements 
                                   : plugin_hash[type].records;
   /*
     Do the alloca out here in case we do have a working alloca:
 	leaving the nested stack frame invalidates alloca allocation.
   */
-  plugins=(struct st_plugin_int **)my_alloca(total*sizeof(*plugins));
+  plugins=(struct st_plugin_int **)my_alloca(total*sizeof(plugin));
   if (type == MYSQL_ANY_PLUGIN)
   {
     for (idx= 0; idx < total; idx++)
@@ -996,20 +1698,20 @@ my_bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
       plugins[idx]= !(plugin->state & state_mask) ? plugin : NULL;
     }
   }
-  rw_unlock(&THR_LOCK_plugin);
+  pthread_mutex_unlock(&LOCK_plugin);
 
   for (idx= 0; idx < total; idx++)
   {
     if (unlikely(version != plugin_array_version))
     {
-      rw_rdlock(&THR_LOCK_plugin);
+      pthread_mutex_lock(&LOCK_plugin);
       for (uint i=idx; i < total; i++)
         if (plugins[i] && plugins[i]->state & state_mask)
           plugins[i]=0;
-      rw_unlock(&THR_LOCK_plugin);
+      pthread_mutex_unlock(&LOCK_plugin);
     }
     plugin= plugins[idx];
-    if (plugin && func(thd, plugin, arg))
+    if (plugin && func(thd, plugin_int_to_ref(plugin), arg))
         goto err;
   }
 
@@ -1020,3 +1722,1320 @@ err:
   DBUG_RETURN(TRUE);
 }
 
+
+/****************************************************************************
+  Internal type declarations for variables support
+****************************************************************************/
+
+#undef MYSQL_SYSVAR_NAME
+#define MYSQL_SYSVAR_NAME(name) name
+#define PLUGIN_VAR_TYPEMASK 0x007f
+
+#define EXTRA_OPTIONS 3 /* options for: 'foo', 'plugin-foo' and NULL */
+
+typedef DECLARE_MYSQL_SYSVAR_BASIC(sysvar_bool_t, my_bool);
+typedef DECLARE_MYSQL_THDVAR_BASIC(thdvar_bool_t, my_bool);
+typedef DECLARE_MYSQL_SYSVAR_BASIC(sysvar_str_t, char *);
+typedef DECLARE_MYSQL_THDVAR_BASIC(thdvar_str_t, char *);
+
+typedef DECLARE_MYSQL_SYSVAR_TYPELIB(sysvar_typelib_t);
+typedef DECLARE_MYSQL_THDVAR_TYPELIB(thdvar_typelib_t);
+
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_int_t, int);
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_long_t, long);
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_longlong_t, longlong);
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_uint_t, uint);
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_ulong_t, ulong);
+typedef DECLARE_MYSQL_SYSVAR_SIMPLE(sysvar_ulonglong_t, ulonglong);
+
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_int_t, int);
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_long_t, long);
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_longlong_t, longlong);
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_uint_t, uint);
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_ulong_t, ulong);
+typedef DECLARE_MYSQL_THDVAR_SIMPLE(thdvar_ulonglong_t, ulonglong);
+
+#define SET_PLUGIN_VAR_RESOLVE(opt)\
+  *(mysql_sys_var_ptr_p*)&((opt)->resolve)= mysql_sys_var_ptr
+typedef byte *(*mysql_sys_var_ptr_p)(void* a_thd, int offset);
+
+
+/****************************************************************************
+  default variable data check and update functions
+****************************************************************************/
+
+static int check_func_bool(THD *thd, struct st_mysql_sys_var *var,
+                           void *save, st_mysql_value *value)
+{
+  char buff[STRING_BUFFER_USUAL_SIZE];
+  const char *strvalue= "NULL", *str;
+  int result, length;
+  ulonglong tmp;
+  
+  if (value->value_type(value) == MYSQL_VALUE_TYPE_STRING)
+  {
+    length= sizeof(buff);
+    if (!(str= value->val_str(value, buff, &length)) ||
+        (result= find_type(&bool_typelib, str, length, 1)-1) < 0)
+    {
+      if (str)
+        strvalue= str;
+      goto err;
+    }
+  }
+  else
+  {
+    if (value->val_int(value, &tmp, sizeof(tmp)) < 0)
+      goto err;
+    if (tmp > 1)
+    {
+      llstr(tmp, buff);
+      strvalue= buff;
+      goto err;
+    }
+    result= (int) tmp;
+  }
+  *(int*)save= -result;
+  return 0;
+err:
+  my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), var->name, strvalue);
+  return 1;
+}
+
+
+static int check_func_int(THD *thd, struct st_mysql_sys_var *var,
+                          void *save, st_mysql_value *value)
+{
+  ulonglong tmp;
+  struct my_option options;
+  value->val_int(value, &tmp, sizeof(tmp));
+  plugin_opt_set_limits(&options, var);
+  *(int *)save= (int) getopt_ull_limit_value(tmp, &options);
+  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) && 
+         (*(int *)save != (int) tmp);
+}
+
+
+static int check_func_long(THD *thd, struct st_mysql_sys_var *var,
+                          void *save, st_mysql_value *value)
+{
+  ulonglong tmp;
+  struct my_option options;
+  value->val_int(value, &tmp, sizeof(tmp));
+  plugin_opt_set_limits(&options, var);
+  *(long *)save= (long) getopt_ull_limit_value(tmp, &options);
+  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) && 
+         (*(long *)save != (long) tmp);
+}
+
+
+static int check_func_longlong(THD *thd, struct st_mysql_sys_var *var,
+                          void *save, st_mysql_value *value)
+{
+  ulonglong tmp;
+  struct my_option options;
+  value->val_int(value, &tmp, sizeof(tmp));
+  plugin_opt_set_limits(&options, var);
+  *(ulonglong *)save= getopt_ull_limit_value(tmp, &options);
+  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) && 
+         (*(ulonglong *)save != tmp);
+}
+
+static int check_func_str(THD *thd, struct st_mysql_sys_var *var,
+                          void *save, st_mysql_value *value)
+{
+  char buff[STRING_BUFFER_USUAL_SIZE];
+  const char *str;
+  int length;
+  
+  length= sizeof(buff);
+  if ((str= value->val_str(value, buff, &length)))
+    str= thd->strmake(str, length);
+  *(const char**)save= str;
+  return 0;
+}
+
+
+static int check_func_enum(THD *thd, struct st_mysql_sys_var *var,
+                           void *save, st_mysql_value *value)
+{
+  char buff[STRING_BUFFER_USUAL_SIZE];
+  const char *strvalue= "NULL", *str;
+  TYPELIB *typelib;
+  ulonglong tmp;
+  long result;
+  int length;
+  
+  if (var->flags & PLUGIN_VAR_THDLOCAL)
+    typelib= ((thdvar_typelib_t*) var)->typelib;
+  else
+    typelib= ((sysvar_typelib_t*) var)->typelib;
+  
+  if (value->value_type(value) == MYSQL_VALUE_TYPE_STRING)
+  {
+    length= sizeof(buff);
+    if (!(str= value->val_str(value, buff, &length)))
+      goto err;
+    if ((result= find_type(typelib, str, length, 1)-1) < 0)
+    {
+      strvalue= str;
+      goto err;
+    }
+  }
+  else
+  {
+    if (value->val_int(value, &tmp, sizeof(tmp)))
+      goto err;
+    if (tmp >= typelib->count)
+    {
+      llstr(tmp, buff);
+      strvalue= buff;
+      goto err;
+    }
+    result= (long) tmp;
+  }
+  *(long*)save= result;
+  return 0;
+err:
+  my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), var->name, strvalue);
+  return 1;
+}
+
+
+static int check_func_set(THD *thd, struct st_mysql_sys_var *var,
+                          void *save, st_mysql_value *value)
+{
+  char buff[STRING_BUFFER_USUAL_SIZE], *error= 0;
+  const char *strvalue= "NULL", *str;
+  TYPELIB *typelib;
+  long result;
+  ulonglong tmp;
+  uint error_len;
+  bool not_used;
+  int length;
+  
+  if (var->flags & PLUGIN_VAR_THDLOCAL)
+    typelib= ((thdvar_typelib_t*) var)->typelib;
+  else
+    typelib= ((sysvar_typelib_t*)var)->typelib;
+
+  if (value->value_type(value) == MYSQL_VALUE_TYPE_STRING)
+  {
+    length= sizeof(buff);
+    if (!(str= value->val_str(value, buff, &length)))
+      goto err;
+    result= find_set(typelib, str, length, NULL,
+                     &error, &error_len, &not_used);
+    if (error_len)
+    {
+      strmake(buff, error, min(sizeof(buff), error_len));
+      strvalue= buff;
+      goto err;
+    }
+  }
+  else
+  {
+    if (value->val_int(value, &tmp, sizeof(tmp)))
+      goto err;
+    if (unlikely((tmp >= (ULL(1) << typelib->count)) &&
+                 (typelib->count < sizeof(long)*8)))
+    {
+      llstr(tmp, buff);
+      strvalue= buff;
+      goto err;
+    }
+    result= (long) tmp;
+  }
+  *(long*)save= result;
+  return 0;
+err:
+  my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), var->name, strvalue);
+  return 1;
+}
+
+
+static void update_func_bool(THD *thd, struct st_mysql_sys_var *var,
+                             void *tgt, void *save)
+{
+  *(my_bool *) tgt= *(int *) save ? 1 : 0;
+}
+
+
+static void update_func_int(THD *thd, struct st_mysql_sys_var *var,
+                             void *tgt, void *save)
+{
+  *(int *)tgt= *(int *) save;
+}
+
+
+static void update_func_long(THD *thd, struct st_mysql_sys_var *var,
+                             void *tgt, void *save)
+{
+  *(long *)tgt= *(long *) save;
+}
+
+
+static void update_func_longlong(THD *thd, struct st_mysql_sys_var *var,
+                             void *tgt, void *save)
+{
+  *(longlong *)tgt= *(ulonglong *) save;
+}
+
+
+static void update_func_str(THD *thd, struct st_mysql_sys_var *var,
+                             void *tgt, void *save)
+{
+  char *old= *(char **) tgt;
+  *(char **)tgt= *(char **) save;
+  if (var->flags & PLUGIN_VAR_MEMALLOC)
+  {
+    *(char **)tgt= my_strdup(*(char **) save, MYF(0));
+    my_free(old, MYF(0));
+  }
+}
+
+
+/****************************************************************************
+  System Variables support
+****************************************************************************/
+
+
+sys_var *find_sys_var(THD *thd, const char *str, uint length)
+{
+  sys_var *var;
+  sys_var_pluginvar *pi= NULL;
+  plugin_ref plugin;
+  DBUG_ENTER("find_sys_var");
+  
+  rw_rdlock(&LOCK_system_variables_hash);
+  if ((var= intern_find_sys_var(str, length, false)) &&
+      (pi= var->cast_pluginvar()))
+  {
+    LEX *lex= thd ? ( !thd->lex ? &thd->main_lex : thd->lex ) : NULL;
+    pthread_mutex_lock(&LOCK_plugin);
+    if (!(plugin= my_intern_plugin_lock(lex, plugin_int_to_ref(pi->plugin))))
+      var= NULL; /* failed to lock it, it must be uninstalling */
+    else
+    if (!(plugin_state(plugin) & PLUGIN_IS_READY))
+    {
+      /* initialization not completed */
+      var= NULL;
+      intern_plugin_unlock(lex, plugin);
+    }
+    pthread_mutex_unlock(&LOCK_plugin);
+  }
+  rw_unlock(&LOCK_system_variables_hash);
+  
+  /*
+    If the variable exists but the plugin it is associated with is not ready
+    then the intern_plugin_lock did not raise an error, so we do it here.
+  */
+  if (pi && !var)
+    my_error(ER_UNKNOWN_SYSTEM_VARIABLE, MYF(0), (char*) str);
+  DBUG_RETURN(var);
+}
+
+
+/*
+  called by register_var, construct_options and test_plugin_options.
+  Returns the 'bookmark' for the named variable.
+  LOCK_system_variables_hash should be at least read locked
+*/
+static st_bookmark *find_bookmark(const char *plugin, const char *name,
+                                  int flags)
+{
+  st_bookmark *result= NULL;
+  uint namelen, length, pluginlen= 0;
+  char *varname, *p;
+  
+  if (!(flags & PLUGIN_VAR_THDLOCAL))
+    return NULL;
+  
+  namelen= strlen(name);
+  if (plugin)
+    pluginlen= strlen(plugin) + 1;
+  length= namelen + pluginlen + 2;
+  varname= (char*) my_alloca(length);
+  
+  if (plugin)
+  {
+    strxmov(varname + 1, plugin, "_", name, NullS);
+    for (p= varname + 1; *p; p++)
+      if (*p == '-')
+	*p= '_';
+  }
+  else
+    memcpy(varname + 1, name, namelen + 1);
+
+  varname[0]= flags & PLUGIN_VAR_TYPEMASK;
+  
+  result= (st_bookmark*) hash_search(&bookmark_hash, 
+                                     (const byte*) varname, length - 1);
+
+  my_afree(varname);
+  return result;
+}
+
+
+/*
+  returns a bookmark for thd-local variables, creating if neccessary.
+  returns null for non thd-local variables.
+  Requires that a write lock is obtained on LOCK_system_variables_hash
+*/
+static st_bookmark *register_var(const char *plugin, const char *name,
+                                 int flags)
+{
+  uint length= strlen(plugin) + strlen(name) + 3, size= 0, offset, new_size;
+  st_bookmark *result;
+  char *varname, *p;
+
+  if (!(flags & PLUGIN_VAR_THDLOCAL))
+    return NULL;
+    
+  switch (flags & PLUGIN_VAR_TYPEMASK) {
+  case PLUGIN_VAR_BOOL:
+    size= sizeof(my_bool);
+    break;
+  case PLUGIN_VAR_INT:
+    size= sizeof(int);
+    break;
+  case PLUGIN_VAR_LONG:
+    size= sizeof(long);
+    break;
+  case PLUGIN_VAR_LONGLONG:
+    size= sizeof(ulonglong);
+    break;
+  case PLUGIN_VAR_STR:
+    size= sizeof(char*);
+    break;
+  default:
+    DBUG_ASSERT(0);
+    return NULL;
+  };
+
+  varname= ((char*) my_alloca(length));
+  strxmov(varname + 1, plugin, "_", name, NullS);
+  for (p= varname + 1; *p; p++)
+    if (*p == '-')
+      *p= '_';
+
+  if (!(result= find_bookmark(NULL, varname + 1, flags)))
+  {
+    result= (st_bookmark*) alloc_root(&plugin_mem_root, 
+                                        sizeof(struct st_bookmark) + length);
+    varname[0]= flags & PLUGIN_VAR_TYPEMASK;
+    result->name= (char *) memcpy(&result[1], varname, length);
+    result->name_len= length - 2;
+    result->offset= -1;
+    
+    DBUG_ASSERT(size && !(size & (size-1))); /* must be power of 2 */
+
+    offset= global_system_variables.dynamic_variables_size;
+    offset= (offset + size - 1) & ~(size - 1);
+    result->offset= (int) offset;
+    
+    new_size= (offset + size + 63) & ~63;
+
+    if (new_size > global_variables_dynamic_size)
+    {
+      global_system_variables.dynamic_variables_ptr=
+        my_realloc(global_system_variables.dynamic_variables_ptr, new_size,
+                   MYF(MY_WME | MY_FAE | MY_ALLOW_ZERO_PTR));
+      max_system_variables.dynamic_variables_ptr=
+        my_realloc(max_system_variables.dynamic_variables_ptr, new_size,
+                   MYF(MY_WME | MY_FAE | MY_ALLOW_ZERO_PTR));
+      global_variables_dynamic_size= new_size;
+    }
+    
+    global_system_variables.dynamic_variables_head= offset;
+    max_system_variables.dynamic_variables_head= offset;
+    global_system_variables.dynamic_variables_size= offset + size;
+    max_system_variables.dynamic_variables_size= offset + size;
+    global_system_variables.dynamic_variables_version++;
+    max_system_variables.dynamic_variables_version++;
+    
+    result->version= global_system_variables.dynamic_variables_version;
+
+    /* this should succeed because we have already checked if a dup exists */
+    if (my_hash_insert(&bookmark_hash, (byte*) result))
+    {
+      fprintf(stderr, "failed to add placeholder to hash");
+      DBUG_ASSERT(0);
+    }
+  }
+  my_afree(varname);
+  return result;
+}
+
+
+/*
+  returns a pointer to the memory which holds the thd-local variable or
+  a pointer to the global variable if thd==null.
+  If required, will sync with global variables if the requested variable
+  has not yet been allocated in the current thread.
+*/
+static byte *intern_sys_var_ptr(THD* thd, int offset, bool global_lock)
+{
+  DBUG_ASSERT(offset >= 0);
+  DBUG_ASSERT((uint)offset <= global_system_variables.dynamic_variables_head);
+  
+  if (!thd)
+    return (byte*) global_system_variables.dynamic_variables_ptr + offset;
+  
+  /*
+    dynamic_variables_size points to the largest valid offset
+  */
+  if (!thd->variables.dynamic_variables_ptr ||
+      (uint)offset > thd->variables.dynamic_variables_head)
+  {
+    uint idx;
+  
+    rw_rdlock(&LOCK_system_variables_hash);
+  
+    thd->variables.dynamic_variables_ptr=
+      my_realloc(thd->variables.dynamic_variables_ptr,
+                 global_variables_dynamic_size,
+                 MYF(MY_WME | MY_FAE | MY_ALLOW_ZERO_PTR));
+
+    if (global_lock)
+      pthread_mutex_lock(&LOCK_global_system_variables);
+
+    safe_mutex_assert_owner(&LOCK_global_system_variables);
+
+    memcpy(thd->variables.dynamic_variables_ptr + 
+             thd->variables.dynamic_variables_size,
+           global_system_variables.dynamic_variables_ptr +
+             thd->variables.dynamic_variables_size,
+           global_system_variables.dynamic_variables_size -
+             thd->variables.dynamic_variables_size);
+    if (global_lock)
+      pthread_mutex_unlock(&LOCK_global_system_variables);
+
+    /*
+      now we need to iterate through any newly copied 'defaults'
+      and if it is a string type with MEMALLOC flag, we need to strdup
+    */
+    for (idx= 0; idx < bookmark_hash.records; idx++)
+    {
+      sys_var_pluginvar *pi;
+      sys_var *var;
+      st_bookmark *v= (st_bookmark*) hash_element(&bookmark_hash,idx);
+      
+      if (v->version <= thd->variables.dynamic_variables_version ||
+          !(var= intern_find_sys_var(v->name + 1, v->name_len, true)) ||
+          !(pi= var->cast_pluginvar()) ||
+          v->name[0] != (pi->plugin_var->flags & PLUGIN_VAR_TYPEMASK))
+        continue;
+
+      /* Here we do anything special that may be required of the data types */
+      
+      if ((pi->plugin_var->flags & PLUGIN_VAR_TYPEMASK) == PLUGIN_VAR_STR &&
+          pi->plugin_var->flags & PLUGIN_VAR_MEMALLOC)
+      {
+         char **pp;
+         if (global_lock)
+           pthread_mutex_lock(&LOCK_global_system_variables);
+         pp= (char**) (thd->variables.dynamic_variables_ptr + 
+                             *(int*)(pi->plugin_var + 1));         
+         if ((*pp= *(char**) (global_system_variables.dynamic_variables_ptr + 
+                             *(int*)(pi->plugin_var + 1))))
+           *pp= my_strdup(*pp, MYF(MY_WME|MY_FAE));
+         if (global_lock)
+           pthread_mutex_unlock(&LOCK_global_system_variables);
+      }
+    }       
+
+    thd->variables.dynamic_variables_version= 
+           global_system_variables.dynamic_variables_version;
+    thd->variables.dynamic_variables_head= 
+           global_system_variables.dynamic_variables_head;
+    thd->variables.dynamic_variables_size= 
+           global_system_variables.dynamic_variables_size;
+
+    rw_unlock(&LOCK_system_variables_hash);
+  }
+  return (byte*)thd->variables.dynamic_variables_ptr + offset;
+}
+
+static byte *mysql_sys_var_ptr(void* a_thd, int offset)
+{
+  return intern_sys_var_ptr((THD *)a_thd, offset, true);
+}
+
+
+void plugin_thdvar_init(THD *thd, bool lock_locals)
+{
+  /* we are going to allocate these lazily */
+  thd->variables.dynamic_variables_version= 0;
+  thd->variables.dynamic_variables_size= 0;
+  thd->variables.dynamic_variables_ptr= 0;
+
+  if (lock_locals)
+  {
+    DBUG_ASSERT(!(thd->variables.table_plugin));
+    thd->variables.table_plugin= 
+        my_plugin_lock(NULL, &global_system_variables.table_plugin);
+  }
+  else
+  {
+    thd->variables.table_plugin= NULL;
+  }
+}
+
+static void cleanup_variables(THD *thd, struct system_variables *vars,
+                              bool free_memory)
+{
+  st_bookmark *v;
+  sys_var_pluginvar *pivar;
+  sys_var *var;
+  int flags;
+  uint idx;
+
+  rw_rdlock(&LOCK_system_variables_hash);
+  for (idx= 0; idx < bookmark_hash.records; idx++)
+  {
+    v= (st_bookmark*) hash_element(&bookmark_hash, idx);
+    if (v->version > vars->dynamic_variables_version ||
+        !(var= intern_find_sys_var(v->name + 1, v->name_len, true)) ||
+        !(pivar= var->cast_pluginvar()) || 
+        v->name[0] != (pivar->plugin_var->flags & PLUGIN_VAR_TYPEMASK))
+      continue;
+
+    flags= pivar->plugin_var->flags;
+    
+    if ((flags & PLUGIN_VAR_TYPEMASK) == PLUGIN_VAR_STR &&
+        flags & PLUGIN_VAR_THDLOCAL && flags & PLUGIN_VAR_MEMALLOC)
+    {
+      char **ptr= (char**) pivar->real_value_ptr(thd, OPT_SESSION);
+      my_free(*ptr, MYF(MY_WME | MY_FAE | MY_ALLOW_ZERO_PTR));
+      *ptr= NULL;
+    }
+  }       
+  rw_unlock(&LOCK_system_variables_hash);
+  
+  intern_plugin_unlock(NULL, vars->table_plugin);
+  vars->table_plugin= NULL;
+  
+  if (free_memory)
+  {
+    my_free(vars->dynamic_variables_ptr, MYF(MY_ALLOW_ZERO_PTR));
+    vars->dynamic_variables_ptr= NULL;
+    vars->dynamic_variables_size= 0;
+    vars->dynamic_variables_version= 0;
+  }
+}
+
+
+void plugin_thdvar_cleanup(THD *thd)
+{
+  uint idx;
+  plugin_ref *list;
+  DBUG_ENTER("plugin_thdvar_cleanup");
+
+  pthread_mutex_lock(&LOCK_plugin);
+
+  cleanup_variables(thd, &thd->variables, true);
+
+  if ((idx= thd->main_lex.plugins.elements))
+  {
+    list= ((plugin_ref*) thd->main_lex.plugins.buffer) + idx - 1;
+    DBUG_PRINT("info",("unlocking %d plugins", idx));
+    while ((char*) list >= thd->main_lex.plugins.buffer)
+      intern_plugin_unlock(NULL, *list--);
+  }
+
+  reap_plugins();
+  pthread_mutex_unlock(&LOCK_plugin);
+
+  reset_dynamic(&thd->main_lex.plugins);
+
+  DBUG_VOID_RETURN;
+}
+
+
+bool sys_var_pluginvar::check_update_type(Item_result type)
+{
+  if (is_readonly())
+    return 1;
+  switch (plugin_var->flags & PLUGIN_VAR_TYPEMASK) {
+  case PLUGIN_VAR_INT:
+  case PLUGIN_VAR_LONG:
+  case PLUGIN_VAR_LONGLONG:
+    return type != INT_RESULT;
+  case PLUGIN_VAR_STR:
+    return type != STRING_RESULT;
+  default:
+    return 0;
+  }
+}
+  
+
+SHOW_TYPE sys_var_pluginvar::show_type()
+{
+  switch (plugin_var->flags & PLUGIN_VAR_TYPEMASK) {
+  case PLUGIN_VAR_BOOL:
+    return SHOW_MY_BOOL;
+  case PLUGIN_VAR_INT:
+    return SHOW_INT;
+  case PLUGIN_VAR_LONG:
+    return SHOW_LONG;
+  case PLUGIN_VAR_LONGLONG:
+    return SHOW_LONGLONG;
+  case PLUGIN_VAR_STR:
+    return SHOW_CHAR_PTR;
+  case PLUGIN_VAR_ENUM:
+  case PLUGIN_VAR_SET:
+    return SHOW_CHAR;
+  default:
+    DBUG_ASSERT(0);
+    return SHOW_UNDEF;
+  }
+}
+  
+
+byte* sys_var_pluginvar::real_value_ptr(THD *thd, enum_var_type type)
+{ 
+  DBUG_ASSERT(thd);
+  if (plugin_var->flags & PLUGIN_VAR_THDLOCAL)
+  {
+    if (type == OPT_GLOBAL)
+      thd= NULL;
+    
+    return intern_sys_var_ptr(thd, *(int*) (plugin_var+1), false);
+  }
+  return *(byte**) (plugin_var+1);
+}
+  
+
+TYPELIB* sys_var_pluginvar::plugin_var_typelib(void)
+{
+  int type= plugin_var->flags & PLUGIN_VAR_TYPEMASK;
+  if (type == PLUGIN_VAR_ENUM || type == PLUGIN_VAR_SET)
+  {
+    if (plugin_var->flags & PLUGIN_VAR_THDLOCAL)
+      return ((thdvar_typelib_t *)plugin_var)->typelib;
+    else
+      return ((sysvar_typelib_t *)plugin_var)->typelib;
+  }
+  return NULL;
+}
+  
+
+byte* sys_var_pluginvar::value_ptr(THD *thd, enum_var_type type,
+                                   LEX_STRING *base)
+{
+  byte* result;
+
+  result= real_value_ptr(thd, type);
+
+  if ((plugin_var->flags && PLUGIN_VAR_TYPEMASK) == PLUGIN_VAR_ENUM)
+    result= (byte*) get_type(plugin_var_typelib(), *(ulong*)result);
+  else
+  if ((plugin_var->flags && PLUGIN_VAR_TYPEMASK) == PLUGIN_VAR_SET)
+  {
+    char buffer[STRING_BUFFER_USUAL_SIZE];
+    String str(buffer, sizeof(buffer), system_charset_info);
+    TYPELIB *typelib= plugin_var_typelib();
+    ulong mask= 1, value= *(ulong*) result;
+    uint i;
+
+    str.length(0);
+    for (i= 0; i < typelib->count; i++, mask<<=1)
+    {
+      if (!(value & mask))
+        continue;
+      str.append(typelib->type_names[i], typelib->type_lengths[i]);
+      str.append(',');
+    }
+
+    result= (byte*) "";
+    if (str.length())
+      result= (byte*) thd->strmake(str.ptr(), str.length()-1);
+  }
+  return result;
+}
+
+
+bool sys_var_pluginvar::check(THD *thd, set_var *var)
+{
+  st_item_value_holder value;
+  DBUG_ASSERT(is_readonly() || plugin_var->check);
+  
+  value.value_type= item_value_type;
+  value.val_str= item_val_str;
+  value.val_int= item_val_int;
+  value.val_real= item_val_real;
+  value.item= var->value;
+  
+  return is_readonly() ||
+         plugin_var->check(thd, plugin_var, &var->save_result, &value);
+}
+
+
+void sys_var_pluginvar::set_default(THD *thd, enum_var_type type)
+{
+  void *tgt, *src;
+
+  DBUG_ASSERT(is_readonly() || plugin_var->update);
+
+  if (is_readonly())
+    return;
+
+  tgt= real_value_ptr(thd, type);
+  src= ((void **) (plugin_var + 1) + 1);
+
+  if (plugin_var->flags & PLUGIN_VAR_THDLOCAL)
+  {
+    src= ((int*) (plugin_var + 1) + 1);
+    if (type != OPT_GLOBAL)
+      src= real_value_ptr(thd, OPT_GLOBAL);
+  }
+
+  /* thd must equal current_thd if PLUGIN_VAR_THDLOCAL flag is set */
+  DBUG_ASSERT(!(plugin_var->flags & PLUGIN_VAR_THDLOCAL) || 
+              thd == current_thd);
+
+  if (!(plugin_var->flags & PLUGIN_VAR_THDLOCAL) || type == OPT_GLOBAL)
+  {
+    pthread_mutex_lock(&LOCK_plugin);
+    plugin_var->update(thd, plugin_var, tgt, src);
+    pthread_mutex_unlock(&LOCK_plugin);
+  }
+  else
+    plugin_var->update(thd, plugin_var, tgt, src);
+}
+  
+
+bool sys_var_pluginvar::update(THD *thd, set_var *var)
+{
+  void *tgt;
+
+  DBUG_ASSERT(is_readonly() || plugin_var->update);
+
+  /* thd must equal current_thd if PLUGIN_VAR_THDLOCAL flag is set */
+  DBUG_ASSERT(!(plugin_var->flags & PLUGIN_VAR_THDLOCAL) || 
+              thd == current_thd);
+
+  if (is_readonly())
+    return 1;
+
+  pthread_mutex_lock(&LOCK_global_system_variables);
+  tgt= real_value_ptr(thd, var->type);
+
+  if (!(plugin_var->flags & PLUGIN_VAR_THDLOCAL) || var->type == OPT_GLOBAL)
+  {
+    /* variable we are updating has global scope, so we unlock after updating */
+    plugin_var->update(thd, plugin_var, tgt, &var->save_result);
+    pthread_mutex_unlock(&LOCK_global_system_variables);
+  }
+  else
+  {
+    pthread_mutex_unlock(&LOCK_global_system_variables);
+    plugin_var->update(thd, plugin_var, tgt, &var->save_result);
+  }
+ return 0;
+}
+
+
+#define OPTION_SET_LIMITS(type, options, opt) \
+  options->var_type= type; \
+  options->def_value= (opt)->def_val; \
+  options->min_value= (opt)->min_val; \
+  options->max_value= (opt)->max_val; \
+  options->block_size= (opt)->blk_sz
+
+
+static void plugin_opt_set_limits(struct my_option *options,
+                                  const struct st_mysql_sys_var *opt)
+{
+  switch (opt->flags & (PLUGIN_VAR_TYPEMASK | 
+                        PLUGIN_VAR_UNSIGNED | PLUGIN_VAR_THDLOCAL)) {
+  /* global system variables */
+  case PLUGIN_VAR_INT:
+    OPTION_SET_LIMITS(GET_INT, options, (sysvar_int_t*) opt);
+    break;
+  case PLUGIN_VAR_INT | PLUGIN_VAR_UNSIGNED:
+    OPTION_SET_LIMITS(GET_UINT, options, (sysvar_uint_t*) opt);
+    break;
+  case PLUGIN_VAR_LONG:
+    OPTION_SET_LIMITS(GET_LONG, options, (sysvar_long_t*) opt);
+    break;
+  case PLUGIN_VAR_LONG | PLUGIN_VAR_UNSIGNED:
+    OPTION_SET_LIMITS(GET_ULONG, options, (sysvar_ulong_t*) opt);
+    break;
+  case PLUGIN_VAR_LONGLONG:
+    OPTION_SET_LIMITS(GET_LL, options, (sysvar_longlong_t*) opt);
+    break;
+  case PLUGIN_VAR_LONGLONG | PLUGIN_VAR_UNSIGNED:
+    OPTION_SET_LIMITS(GET_ULL, options, (sysvar_ulonglong_t*) opt);
+    break;
+  case PLUGIN_VAR_ENUM:
+    options->var_type= GET_ENUM;
+    options->typelib= ((sysvar_typelib_t*) opt)->typelib;
+    options->def_value= *(ulong*) ((int*) (opt + 1) + 1);
+    options->min_value= options->block_size= 0;
+    options->max_value= options->typelib->count - 1;
+    break;
+  case PLUGIN_VAR_SET:
+    options->var_type= GET_SET;
+    options->typelib= ((sysvar_typelib_t*) opt)->typelib;
+    options->def_value= *(ulong*) ((int*) (opt + 1) + 1);
+    options->min_value= options->block_size= 0;
+    options->max_value= (ULL(1) << options->typelib->count) - 1;
+    break;
+  case PLUGIN_VAR_BOOL:
+    options->var_type= GET_BOOL;
+    options->def_value= *(my_bool*) ((void**)(opt + 1) + 1);
+    break;
+  case PLUGIN_VAR_STR:
+    options->var_type= GET_STR;
+    break;
+  /* threadlocal variables */
+  case PLUGIN_VAR_INT | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_INT, options, (thdvar_int_t*) opt);
+    break;
+  case PLUGIN_VAR_INT | PLUGIN_VAR_UNSIGNED | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_UINT, options, (thdvar_uint_t*) opt);
+    break;
+  case PLUGIN_VAR_LONG | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_LONG, options, (thdvar_long_t*) opt);
+    break;
+  case PLUGIN_VAR_LONG | PLUGIN_VAR_UNSIGNED | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_ULONG, options, (thdvar_ulong_t*) opt);
+    break;
+  case PLUGIN_VAR_LONGLONG | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_LL, options, (thdvar_longlong_t*) opt);
+    break;
+  case PLUGIN_VAR_LONGLONG | PLUGIN_VAR_UNSIGNED | PLUGIN_VAR_THDLOCAL:
+    OPTION_SET_LIMITS(GET_ULL, options, (thdvar_ulonglong_t*) opt);
+    break;
+  case PLUGIN_VAR_ENUM | PLUGIN_VAR_THDLOCAL:
+    options->var_type= GET_ENUM;
+    options->typelib= ((thdvar_typelib_t*) opt)->typelib;
+    options->def_value= *(ulong*) ((int*) (opt + 1) + 1);
+    options->min_value= options->block_size= 0;
+    options->max_value= options->typelib->count - 1;
+    break;
+  case PLUGIN_VAR_SET | PLUGIN_VAR_THDLOCAL:
+    options->var_type= GET_SET;
+    options->typelib= ((thdvar_typelib_t*) opt)->typelib;
+    options->def_value= *(ulong*) ((int*) (opt + 1) + 1);
+    options->min_value= options->block_size= 0;
+    options->max_value= (ULL(1) << options->typelib->count) - 1;
+    break;
+  case PLUGIN_VAR_BOOL | PLUGIN_VAR_THDLOCAL:
+    options->var_type= GET_BOOL;
+    options->def_value= *(my_bool*) ((int*) (opt + 1) + 1);
+    break;
+  case PLUGIN_VAR_STR | PLUGIN_VAR_THDLOCAL:
+    options->var_type= GET_STR;
+    break;
+  default:
+    DBUG_ASSERT(0);
+  }
+  options->arg_type= REQUIRED_ARG;
+  if (opt->flags & PLUGIN_VAR_NOCMDARG)
+    options->arg_type= NO_ARG;
+  if (opt->flags & PLUGIN_VAR_OPCMDARG)
+    options->arg_type= OPT_ARG;    
+}
+
+
+static my_bool get_one_option(int optid __attribute__((unused)),
+                              const struct my_option *opt,
+                              char *argument)
+{
+  return 0;
+}
+
+
+static int construct_options(MEM_ROOT *mem_root,
+                             struct st_plugin_int *tmp,
+                             my_option *options,
+                             my_bool **enabled, bool can_disable)
+{
+  const char *plugin_name= tmp->plugin->name;
+  uint namelen= strlen(plugin_name), optnamelen;
+  uint buffer_length= namelen * 4 + (can_disable ? 75 : 10);
+  char *name= (char*) alloc_root(mem_root, buffer_length) + 1;
+  char *optname, *p;
+  int index= 0, offset= 0;
+  st_mysql_sys_var *opt, **plugin_option;
+  st_bookmark *v;
+  DBUG_ENTER("construct_options");
+    
+  /* support --skip-plugin-foo syntax */
+  memcpy(name, plugin_name, namelen + 1);
+  my_casedn_str(&my_charset_latin1, name);
+  strxmov(name + namelen + 1, "plugin-", name, NullS);
+  
+  for (p= name + namelen*2 + 8; p > name; p--)
+    if (*p == '_')
+      *p= '-';
+  
+  if (can_disable)
+  {
+    strxmov(name + namelen*2 + 10, "Enable ", plugin_name, " plugin. "
+            "Disable with --skip-plugin-", name," (will save memory).", NullS);
+
+    options[0].comment= name + namelen*2 + 10;
+  }
+
+  *((my_bool *)(name -1))= **enabled;
+  *enabled= (my_bool *)(name - 1);
+  
+  
+  options[1].name= (options[0].name= name) + namelen + 1;
+  options[0].id= options[1].id= 256; /* must be >255. dup id ok */
+  options[0].var_type= options[1].var_type= GET_BOOL;
+  options[0].arg_type= options[1].arg_type= NO_ARG;
+  options[0].def_value= options[1].def_value= **enabled;
+  options[0].value= options[0].u_max_value=
+  options[1].value= options[1].u_max_value= (gptr*) (name - 1);
+  options+= 2;
+
+  /*
+    Two passes as the 2nd pass will take pointer addresses for use
+    by my_getopt and register_var() in the first pass uses realloc
+  */
+
+  for (plugin_option= tmp->plugin->system_vars; 
+       plugin_option && *plugin_option; plugin_option++, index++)
+  {
+    opt= *plugin_option;    
+    if (!(opt->flags & PLUGIN_VAR_THDLOCAL))
+      continue;
+    if (!(register_var(name, opt->name, opt->flags)))
+      continue;
+    switch (opt->flags & PLUGIN_VAR_TYPEMASK) {
+    case PLUGIN_VAR_BOOL:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_bool_t *) opt);
+      break;
+    case PLUGIN_VAR_INT:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_int_t *) opt);
+      break;
+    case PLUGIN_VAR_LONG:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_long_t *) opt);
+      break;
+    case PLUGIN_VAR_LONGLONG:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_longlong_t *) opt);
+      break;
+    case PLUGIN_VAR_STR:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_str_t *) opt);
+      break;
+    case PLUGIN_VAR_ENUM:
+    case PLUGIN_VAR_SET:
+      SET_PLUGIN_VAR_RESOLVE((thdvar_typelib_t *) opt);
+      break;
+    default:
+      sql_print_error("Unknown variable type code 0x%x in plugin '%s'.",
+                      opt->flags, tmp->plugin->name);
+      DBUG_RETURN(-1);
+    };
+  }
+
+  for (plugin_option= tmp->plugin->system_vars; 
+       plugin_option && *plugin_option; plugin_option++, index++)
+  {
+    switch ((opt= *plugin_option)->flags & PLUGIN_VAR_TYPEMASK) {
+    case PLUGIN_VAR_BOOL:
+      if (!opt->check)
+        opt->check= check_func_bool;
+      if (!opt->update)
+        opt->update= update_func_bool;
+      break;
+    case PLUGIN_VAR_INT:
+      if (!opt->check)
+        opt->check= check_func_int;
+      if (!opt->update)
+        opt->update= update_func_int;
+      break;
+    case PLUGIN_VAR_LONG:
+      if (!opt->check)
+        opt->check= check_func_long;
+      if (!opt->update)
+        opt->update= update_func_long;
+      break;
+    case PLUGIN_VAR_LONGLONG:
+      if (!opt->check)
+        opt->check= check_func_longlong;
+      if (!opt->update)
+        opt->update= update_func_longlong;
+      break;
+    case PLUGIN_VAR_STR:
+      if (!opt->check)
+        opt->check= check_func_str;
+      if (!opt->update)
+      {
+        opt->update= update_func_str;
+        if (!(opt->flags & PLUGIN_VAR_MEMALLOC))
+          opt->flags |= PLUGIN_VAR_READONLY;
+      }
+      break;
+    case PLUGIN_VAR_ENUM:
+      if (!opt->check)
+        opt->check= check_func_enum;
+      if (!opt->update)
+        opt->update= update_func_long;
+      break;
+    case PLUGIN_VAR_SET:
+      if (!opt->check)
+        opt->check= check_func_set;
+      if (!opt->update)
+        opt->update= update_func_long;
+      break;
+    default:
+      sql_print_error("Unknown variable type code 0x%x in plugin '%s'.",
+                      opt->flags, tmp->plugin->name);
+      DBUG_RETURN(-1);
+    }
+  
+    if (opt->flags & PLUGIN_VAR_NOCMDOPT)
+      continue;
+
+    if (!opt->name)
+    {
+      sql_print_error("Missing variable name in plugin '%s'.",
+                      tmp->plugin->name);
+      DBUG_RETURN(-1);
+    }
+
+    if (!(v= find_bookmark(name, opt->name, opt->flags)))
+    {
+      optnamelen= strlen(opt->name);
+      optname= (char*) alloc_root(mem_root, namelen + optnamelen + 2);
+      strxmov(optname, name, "-", opt->name, NullS);
+      optnamelen= namelen + optnamelen + 1;
+    }
+    else
+      optname= memdup_root(mem_root, v->name + 1, (optnamelen= v->name_len) + 1);
+
+    /* convert '_' to '-' */
+    for (p= optname; *p; p++)
+      if (*p == '_')
+        *p= '-';
+
+    options->name= optname;
+    options->comment= opt->comment;
+    options->app_type= (long) opt;
+    options->id= (options-1)->id + 1;
+    
+    if (opt->flags & PLUGIN_VAR_THDLOCAL)
+      *(int*)(opt + 1)= offset= v->offset;
+
+    plugin_opt_set_limits(options, opt);
+    
+    if ((opt->flags & PLUGIN_VAR_TYPEMASK) != PLUGIN_VAR_ENUM &&
+        (opt->flags & PLUGIN_VAR_TYPEMASK) != PLUGIN_VAR_SET)
+    {
+      if (opt->flags & PLUGIN_VAR_THDLOCAL)
+        options->value= options->u_max_value= (gptr*)
+          (global_system_variables.dynamic_variables_ptr + offset);
+      else
+        options->value= options->u_max_value= *(gptr**) (opt + 1);
+    }
+
+    options[1]= options[0];
+    options[1].name= p= (char*) alloc_root(mem_root, optnamelen + 8);
+    options[1].comment= NULL; /* hide this option */
+    strxmov(p, "plugin-", optname, NullS);
+
+    options+= 2;
+  }
+
+  DBUG_RETURN(0);
+}
+
+
+static my_option *construct_help_options(MEM_ROOT *mem_root,
+                                         struct st_plugin_int *p)
+{
+  st_mysql_sys_var **opt;
+  my_option *opts;
+  my_bool dummy;
+  my_bool *dummy2= &dummy;
+  uint count= EXTRA_OPTIONS;
+  DBUG_ENTER("construct_help_options");
+
+  for (opt= p->plugin->system_vars; opt && *opt; opt++, count++);
+
+  if (!(opts= (my_option*) alloc_root(mem_root, sizeof(my_option) * count)))
+    DBUG_RETURN(NULL);
+
+  bzero(opts, sizeof(my_option) * count);
+
+  if (construct_options(mem_root, p, opts, &dummy2, FALSE))
+    DBUG_RETURN(NULL);
+
+  DBUG_RETURN(opts);
+}
+
+
+/*
+  SYNOPSIS
+    test_plugin_options()
+    tmp_root                    temporary scratch space
+    plugin                      internal plugin structure
+    argc                        user supplied arguments
+    argv                        user supplied arguments
+    default_enabled             default plugin enable status
+  RETURNS:
+    0 SUCCESS - plugin should be enabled/loaded
+  NOTE:
+    Requires that a write-lock is held on LOCK_system_variables_hash
+*/
+static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
+                               int *argc, char **argv, my_bool default_enabled)
+{
+  struct sys_var_chain chain= { NULL, NULL };
+  my_bool enabled_saved= default_enabled, can_disable;
+  my_bool *enabled= &default_enabled;
+  MEM_ROOT *mem_root= alloc_root_inited(&tmp->mem_root) ? 
+                      &tmp->mem_root : &plugin_mem_root;
+  st_mysql_sys_var **opt;
+  my_option *opts;
+  char *p, *varname;
+  int error;
+  st_mysql_sys_var *o;
+  sys_var *v;
+  struct st_bookmark *var;
+  uint len, count= EXTRA_OPTIONS;
+  DBUG_ENTER("test_plugin_options");
+  DBUG_ASSERT(tmp->plugin && tmp->plugin->name);
+
+  for (opt= tmp->plugin->system_vars; opt && *opt; opt++)
+    count+= 2; /* --{plugin}-{optname} and --plugin-{plugin}-{optname} */
+
+  can_disable=
+      my_strcasecmp(&my_charset_latin1, tmp->plugin->name, "MyISAM") &&
+      my_strcasecmp(&my_charset_latin1, tmp->plugin->name, "MEMORY");
+  
+  if (count > EXTRA_OPTIONS || (*argc > 1))
+  {  
+    if (!(opts= (my_option*) alloc_root(tmp_root, sizeof(my_option) * count)))
+    {
+      sql_print_error("Out of memory for plugin '%s'.", tmp->plugin->name);
+      DBUG_RETURN(-1);
+    }
+    bzero(opts, sizeof(my_option) * count);
+    
+    if (construct_options(tmp_root, tmp, opts, &enabled, can_disable))
+    {
+      sql_print_error("Bad options for plugin '%s'.", tmp->plugin->name);
+      DBUG_RETURN(-1);
+    }
+
+    error= handle_options(argc, &argv, opts, get_one_option);
+    (*argc)++; /* add back one for the program name */
+    
+    if (error)
+    {
+       sql_print_error("Parsing options for plugin '%s' failed.", 
+                       tmp->plugin->name);
+       DBUG_RETURN(error);
+    }
+  }
+
+  if (!*enabled && !can_disable)
+  {
+    sql_print_warning("Plugin '%s' cannot be disabled", tmp->plugin->name);
+    *enabled= TRUE;
+  }
+
+  if (*enabled)
+  {    
+    for (opt= tmp->plugin->system_vars; opt && *opt; opt++)
+    {
+      if (((o= *opt)->flags & PLUGIN_VAR_NOSYSVAR))
+        continue;
+      
+      if ((var= find_bookmark(tmp->plugin->name, o->name, o->flags)))
+        v= new (mem_root) sys_var_pluginvar(var->name + 1, tmp, o);
+      else
+      {
+        len= strlen(tmp->plugin->name) + strlen(o->name) + 2;
+        varname= (char*) alloc_root(mem_root, len);
+        strxmov(varname, tmp->plugin->name, "-", o->name, NullS);
+        my_casedn_str(&my_charset_latin1, varname);
+
+        for (p= varname; *p; p++)
+          if (*p == '-')
+            *p= '_';
+
+        v= new (mem_root) sys_var_pluginvar(varname, tmp, o);
+      }
+      DBUG_ASSERT(v); /* check that an object was actually constructed */
+
+      v->chain_sys_var(&chain);
+    }
+    if (chain.first)
+    {
+      chain.last->next = NULL;
+      if (mysql_add_sys_var_chain(chain.first, NULL))
+      {
+        sql_print_error("Plugin '%s' has conflicting system variables",
+                        tmp->plugin->name);
+        DBUG_RETURN(1);  
+      }
+      tmp->system_vars= chain.first;
+    }
+    DBUG_RETURN(0);
+  }
+
+  if (enabled_saved)
+    sql_print_information("Plugin '%s' disabled by command line option",
+                          tmp->plugin->name);
+  DBUG_RETURN(1);
+}
+
+
+/****************************************************************************
+  Help Verbose text with Plugin System Variables
+****************************************************************************/
+
+static int option_cmp(my_option *a, my_option *b)
+{
+  return my_strcasecmp(&my_charset_latin1, a->name, b->name);
+}
+
+
+void my_print_help_inc_plugins(my_option *main_options, uint size)
+{
+  DYNAMIC_ARRAY all_options;
+  struct st_plugin_int *p;
+  MEM_ROOT mem_root;
+  my_option *opt;
+
+  init_alloc_root(&mem_root, 4096, 4096);
+  my_init_dynamic_array(&all_options, sizeof(my_option), size, size/4);
+  
+  if (initialized)
+    for (uint idx= 0; idx < plugin_array.elements; idx++)
+    {
+      p= dynamic_element(&plugin_array, idx, struct st_plugin_int *);
+
+      if (!p->plugin->system_vars ||
+          !(opt= construct_help_options(&mem_root, p)))
+        continue;
+
+      /* Only options with a non-NULL comment are displayed in help text */
+      for (;opt->id; opt++)
+        if (opt->comment)
+          insert_dynamic(&all_options, (gptr) opt);
+    }
+  
+  for (;main_options->id; main_options++)
+    insert_dynamic(&all_options, (gptr) main_options);
+  
+  sort_dynamic(&all_options, (qsort_cmp) option_cmp);
+  
+  /* main_options now points to the empty option terminator */
+  insert_dynamic(&all_options, (gptr) main_options);
+  
+  my_print_help((my_option*) all_options.buffer);
+  my_print_variables((my_option*) all_options.buffer);
+
+  delete_dynamic(&all_options);
+  free_root(&mem_root, MYF(0));
+}
+
diff --git a/sql/sql_plugin.h b/sql/sql_plugin.h
index d86d9332a92..b3293f3ebda 100644
--- a/sql/sql_plugin.h
+++ b/sql/sql_plugin.h
@@ -16,6 +16,17 @@
 #ifndef _sql_plugin_h
 #define _sql_plugin_h
 
+class sys_var;
+
+/*
+  the following flags are valid for plugin_init()
+*/
+#define PLUGIN_INIT_SKIP_DYNAMIC_LOADING 1
+#define PLUGIN_INIT_SKIP_PLUGIN_TABLE    2
+#define PLUGIN_INIT_SKIP_INITIALIZATION  4
+
+#define INITIAL_LEX_PLUGIN_LIST_SIZE    16
+
 /*
   the following #define adds server-only members to enum_mysql_show_type,
   that is defined in plugin.h
@@ -41,6 +52,7 @@ typedef struct st_mysql_show_var SHOW_VAR;
 #define PLUGIN_IS_DELETED       2
 #define PLUGIN_IS_UNINITIALIZED 4
 #define PLUGIN_IS_READY         8
+#define PLUGIN_IS_DYING         16
 
 /* A handle for the dynamic library containing a plugin or plugins. */
 
@@ -63,25 +75,57 @@ struct st_plugin_int
   uint state;
   uint ref_count;               /* number of threads using the plugin */
   void *data;                   /* plugin type specific, e.g. handlerton */
+  MEM_ROOT mem_root;            /* memory for dynamic plugin structures */
+  sys_var *system_vars;         /* server variables for this plugin */
 };
 
+#ifdef DBUG_OFF
+typedef struct st_plugin_int *plugin_ref;
+#define plugin_decl(pi) ((pi)->plugin)
+#define plugin_dlib(pi) ((pi)->plugin_dl)
+#define plugin_data(pi,cast) ((cast)((pi)->data))
+#define plugin_name(pi) (&((pi)->name))
+#define plugin_state(pi) ((pi)->state)
+#else
+typedef struct st_plugin_int **plugin_ref;
+#define plugin_decl(pi) ((pi)[0]->plugin)
+#define plugin_dlib(pi) ((pi)[0]->plugin_dl)
+#define plugin_data(pi,cast) ((cast)((pi)[0]->data))
+#define plugin_name(pi) (&((pi)[0]->name))
+#define plugin_state(pi) ((pi)[0]->state)
+#endif
+
 typedef int (*plugin_type_init)(struct st_plugin_int *);
 
+extern char *opt_plugin_load;
 extern char *opt_plugin_dir_ptr;
 extern char opt_plugin_dir[FN_REFLEN];
 extern const LEX_STRING plugin_type_names[];
-extern int plugin_init(int);
+
+extern int plugin_init(int *argc, char **argv, int init_flags);
 extern void plugin_shutdown(void);
-extern my_bool plugin_is_ready(const LEX_STRING *name, int type);
-extern st_plugin_int *plugin_lock(const LEX_STRING *name, int type);
-extern void plugin_unlock(struct st_plugin_int *plugin);
-extern my_bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl);
-extern my_bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name);
+extern void my_print_help_inc_plugins(struct my_option *options, uint size);
+extern bool plugin_is_ready(const LEX_STRING *name, int type);
+#define my_plugin_lock_by_name(A,B,C) plugin_lock_by_name(A,B,C CALLER_INFO)
+#define my_plugin_lock_by_name_ci(A,B,C) plugin_lock_by_name(A,B,C ORIG_CALLER_INFO)
+#define my_plugin_lock(A,B) plugin_lock(A,B CALLER_INFO)
+#define my_plugin_lock_ci(A,B) plugin_lock(A,B ORIG_CALLER_INFO)
+extern plugin_ref plugin_lock(THD *thd, plugin_ref *ptr CALLER_INFO_PROTO);
+extern plugin_ref plugin_lock_by_name(THD *thd, const LEX_STRING *name,
+                                      int type CALLER_INFO_PROTO);
+extern void plugin_unlock(THD *thd, plugin_ref plugin);
+extern void plugin_unlock_list(THD *thd, plugin_ref *list, uint count);
+extern bool mysql_install_plugin(THD *thd, const LEX_STRING *name,
+                                 const LEX_STRING *dl);
+extern bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name);
+extern bool plugin_register_builtin(struct st_mysql_plugin *plugin);
+extern void plugin_thdvar_init(THD *thd, bool lock_locals);
+extern void plugin_thdvar_cleanup(THD *thd);
 
 typedef my_bool (plugin_foreach_func)(THD *thd,
-                                      st_plugin_int *plugin,
+                                      plugin_ref plugin,
                                       void *arg);
 #define plugin_foreach(A,B,C,D) plugin_foreach_with_mask(A,B,C,PLUGIN_IS_READY,D)
-extern my_bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
-                                        int type, uint state_mask, void *arg);
+extern bool plugin_foreach_with_mask(THD *thd, plugin_foreach_func *func,
+                                     int type, uint state_mask, void *arg);
 #endif
diff --git a/sql/sql_repl.cc b/sql/sql_repl.cc
index 17163fb1940..589381ca61f 100644
--- a/sql/sql_repl.cc
+++ b/sql/sql_repl.cc
@@ -1596,6 +1596,149 @@ int log_loaded_block(IO_CACHE* file)
   return 0;
 }
 
+/*
+  Replication System Variables
+*/
+
+class sys_var_slave_skip_counter :public sys_var
+{
+public:
+  sys_var_slave_skip_counter(sys_var_chain *chain, const char *name_arg)
+    :sys_var(name_arg)
+  { chain_sys_var(chain); }
+  bool check(THD *thd, set_var *var);
+  bool update(THD *thd, set_var *var);
+  bool check_type(enum_var_type type) { return type != OPT_GLOBAL; }
+  /*
+    We can't retrieve the value of this, so we don't have to define
+    type() or value_ptr()
+  */
+};
+
+class sys_var_sync_binlog_period :public sys_var_long_ptr
+{
+public:
+  sys_var_sync_binlog_period(sys_var_chain *chain, const char *name_arg, 
+                             ulong *value_ptr)
+    :sys_var_long_ptr(chain, name_arg,value_ptr) {}
+  bool update(THD *thd, set_var *var);
+};
+
+static sys_var_chain vars = { NULL, NULL };
+
+static sys_var_bool_ptr	sys_relay_log_purge(&vars, "relay_log_purge",
+					    &relay_log_purge);
+static sys_var_long_ptr	sys_slave_net_timeout(&vars, "slave_net_timeout",
+					      &slave_net_timeout);
+static sys_var_long_ptr	sys_slave_trans_retries(&vars, "slave_transaction_retries",
+						&slave_trans_retries);
+static sys_var_sync_binlog_period sys_sync_binlog_period(&vars, "sync_binlog", &sync_binlog_period);
+static sys_var_slave_skip_counter sys_slave_skip_counter(&vars, "sql_slave_skip_counter");
+
+static int show_slave_skip_errors(THD *thd, SHOW_VAR *var, char *buff);
+
+
+static SHOW_VAR fixed_vars[]= {
+  {"log_slave_updates",       (char*) &opt_log_slave_updates,       SHOW_MY_BOOL},
+  {"relay_log_space_limit",   (char*) &relay_log_space_limit,       SHOW_LONGLONG},
+  {"slave_load_tmpdir",       (char*) &slave_load_tmpdir,           SHOW_CHAR_PTR},
+  {"slave_skip_errors",       (char*) &show_slave_skip_errors,      SHOW_FUNC},
+};
+
+static int show_slave_skip_errors(THD *thd, SHOW_VAR *var, char *buff)
+{
+  var->type=SHOW_CHAR;
+  var->value= buff;
+  if (!use_slave_mask || bitmap_is_clear_all(&slave_error_mask))
+  {
+    var->value= const_cast<char *>("OFF");
+  }
+  else if (bitmap_is_set_all(&slave_error_mask))
+  {
+    var->value= const_cast<char *>("ALL");
+  }
+  else
+  {
+    /* 10 is enough assuming errors are max 4 digits */
+    int i;
+    var->value= buff;
+    for (i= 1;
+         i < MAX_SLAVE_ERROR &&
+         (buff - var->value) < SHOW_VAR_FUNC_BUFF_SIZE;
+         i++)
+    {
+      if (bitmap_is_set(&slave_error_mask, i))
+      {
+        buff= int10_to_str(i, buff, 10);
+        *buff++= ',';
+      }
+    }
+    if (var->value != buff)
+      buff--;				// Remove last ','
+    if (i < MAX_SLAVE_ERROR)
+      buff= strmov(buff, "...");  // Couldn't show all errors
+    *buff=0;
+  }
+  return 0;
+}
+
+bool sys_var_slave_skip_counter::check(THD *thd, set_var *var)
+{
+  int result= 0;
+  pthread_mutex_lock(&LOCK_active_mi);
+  pthread_mutex_lock(&active_mi->rli.run_lock);
+  if (active_mi->rli.slave_running)
+  {
+    my_message(ER_SLAVE_MUST_STOP, ER(ER_SLAVE_MUST_STOP), MYF(0));
+    result=1;
+  }
+  pthread_mutex_unlock(&active_mi->rli.run_lock);
+  pthread_mutex_unlock(&LOCK_active_mi);
+  var->save_result.ulong_value= (ulong) var->value->val_int();
+  return result;
+}
+
+
+bool sys_var_slave_skip_counter::update(THD *thd, set_var *var)
+{
+  pthread_mutex_lock(&LOCK_active_mi);
+  pthread_mutex_lock(&active_mi->rli.run_lock);
+  /*
+    The following test should normally never be true as we test this
+    in the check function;  To be safe against multiple
+    SQL_SLAVE_SKIP_COUNTER request, we do the check anyway
+  */
+  if (!active_mi->rli.slave_running)
+  {
+    pthread_mutex_lock(&active_mi->rli.data_lock);
+    active_mi->rli.slave_skip_counter= var->save_result.ulong_value;
+    pthread_mutex_unlock(&active_mi->rli.data_lock);
+  }
+  pthread_mutex_unlock(&active_mi->rli.run_lock);
+  pthread_mutex_unlock(&LOCK_active_mi);
+  return 0;
+}
+
+
+bool sys_var_sync_binlog_period::update(THD *thd, set_var *var)
+{
+  sync_binlog_period= (ulong) var->save_result.ulonglong_value;
+  return 0;
+}
+
+int init_replication_sys_vars()
+{
+  mysql_append_static_vars(fixed_vars, sizeof(fixed_vars) / sizeof(SHOW_VAR));
+
+  if (mysql_add_sys_var_chain(vars.first, my_long_options))
+  {
+    /* should not happen */
+    fprintf(stderr, "failed to initialize replication system variables");
+    unireg_abort(1);
+  }
+  return 0;
+}
+
 #endif /* HAVE_REPLICATION */
 
 
diff --git a/sql/sql_repl.h b/sql/sql_repl.h
index b106391245d..da50d47c60d 100644
--- a/sql/sql_repl.h
+++ b/sql/sql_repl.h
@@ -67,6 +67,7 @@ typedef struct st_load_file_info
 } LOAD_FILE_INFO;
 
 int log_loaded_block(IO_CACHE* file);
+int init_replication_sys_vars();
 
 #endif /* HAVE_REPLICATION */
 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 75b3f5ae981..47495cb5ec3 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -9458,12 +9458,14 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   share->fields= field_count;
 
   /* If result table is small; use a heap */
+  /* future: storage engine selection can be made dynamic? */
   if (blob_count || using_unique_constraint ||
       (select_options & (OPTION_BIG_TABLES | SELECT_SMALL_RESULT)) ==
       OPTION_BIG_TABLES || (select_options & TMP_TABLE_FORCE_MYISAM))
   {
+    share->db_plugin= ha_lock_engine(0, myisam_hton);
     table->file= get_new_handler(share, &table->mem_root,
-                                 share->db_type= myisam_hton);
+                                 share->db_type());
     if (group &&
 	(param->group_parts > table->file->max_key_parts() ||
 	 param->group_length > table->file->max_key_length()))
@@ -9471,8 +9473,9 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   }
   else
   {
+    share->db_plugin= ha_lock_engine(0, heap_hton);
     table->file= get_new_handler(share, &table->mem_root,
-                                 share->db_type= heap_hton);
+                                 share->db_type());
   }
   if (!table->file)
     goto err;
@@ -9633,7 +9636,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   if (thd->variables.tmp_table_size == ~ (ulonglong) 0)		// No limit
     share->max_rows= ~(ha_rows) 0;
   else
-    share->max_rows= (ha_rows) (((share->db_type == heap_hton) ?
+    share->max_rows= (ha_rows) (((share->db_type() == heap_hton) ?
                                  min(thd->variables.tmp_table_size,
                                      thd->variables.max_heap_table_size) :
                                  thd->variables.tmp_table_size) /
@@ -9781,7 +9784,7 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   if (thd->is_fatal_error)				// If end of memory
     goto err;					 /* purecov: inspected */
   share->db_record_offset= 1;
-  if (share->db_type == myisam_hton)
+  if (share->db_type() == myisam_hton)
   {
     if (create_myisam_tmp_table(table,param,select_options))
       goto err;
@@ -10088,6 +10091,8 @@ free_tmp_table(THD *thd, TABLE *entry)
   if (entry->temp_pool_slot != MY_BIT_NONE)
     bitmap_lock_clear_bit(&temp_pool, entry->temp_pool_slot);
 
+  plugin_unlock(0, entry->s->db_plugin);
+
   free_root(&own_root, MYF(0)); /* the table is allocated in its own root */
   thd->proc_info=save_proc_info;
 
@@ -10107,7 +10112,7 @@ bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
   int write_err;
   DBUG_ENTER("create_myisam_from_heap");
 
-  if (table->s->db_type != heap_hton || 
+  if (table->s->db_type() != heap_hton || 
       error != HA_ERR_RECORD_FILE_FULL)
   {
     table->file->print_error(error,MYF(0));
@@ -10116,9 +10121,9 @@ bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
   new_table= *table;
   share= *table->s;
   new_table.s= &share;
-  new_table.s->db_type= myisam_hton;
+  new_table.s->db_plugin= ha_lock_engine(thd, myisam_hton);
   if (!(new_table.file= get_new_handler(&share, &new_table.mem_root,
-                                        myisam_hton)))
+                                        new_table.s->db_type())))
     DBUG_RETURN(1);				// End of memory
 
   save_proc_info=thd->proc_info;
@@ -10176,9 +10181,12 @@ bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
   (void) table->file->delete_table(table->s->table_name.str);
   delete table->file;
   table->file=0;
+  plugin_unlock(0, table->s->db_plugin);
+  share.db_plugin= my_plugin_lock(0, &share.db_plugin);
   new_table.s= table->s;                       // Keep old share
   *table= new_table;
   *table->s= share;
+  
   table->file->change_table_ptr(table, table->s);
   table->use_all_columns();
   if (save_proc_info)
@@ -12761,7 +12769,7 @@ remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
 
   free_io_cache(entry);				// Safety
   entry->file->info(HA_STATUS_VARIABLE);
-  if (entry->s->db_type == heap_hton ||
+  if (entry->s->db_type() == heap_hton ||
       (!entry->s->blob_fields &&
        ((ALIGN_SIZE(reclength) + HASH_OVERHEAD) * entry->file->stats.records <
 	thd->variables.sortbuff_size)))
diff --git a/sql/sql_show.cc b/sql/sql_show.cc
index 250d9d917eb..17f9c516971 100644
--- a/sql/sql_show.cc
+++ b/sql/sql_show.cc
@@ -77,24 +77,24 @@ append_algorithm(TABLE_LIST *table, String *buff);
 ** List all table types supported
 ***************************************************************************/
 
-static my_bool show_handlerton(THD *thd, st_plugin_int *plugin,
+static my_bool show_handlerton(THD *thd, plugin_ref plugin,
                                void *arg)
 {
   handlerton *default_type= (handlerton *) arg;
   Protocol *protocol= thd->protocol;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
 
   if (!(hton->flags & HTON_HIDDEN))
   {
     protocol->prepare_for_resend();
-    protocol->store(plugin->name.str, plugin->name.length,
+    protocol->store(plugin_name(plugin)->str, plugin_name(plugin)->length,
                     system_charset_info);
     const char *option_name= show_comp_option_name[(int) hton->state];
 
     if (hton->state == SHOW_OPTION_YES && default_type == hton)
       option_name= "DEFAULT";
     protocol->store(option_name, system_charset_info);
-    protocol->store(plugin->plugin->descr, system_charset_info);
+    protocol->store(plugin_decl(plugin)->descr, system_charset_info);
     protocol->store(hton->commit ? "YES" : "NO", system_charset_info);
     protocol->store(hton->prepare ? "YES" : "NO", system_charset_info);
     protocol->store(hton->savepoint_set ? "YES" : "NO", system_charset_info);
@@ -122,7 +122,7 @@ bool mysqld_show_storage_engines(THD *thd)
     DBUG_RETURN(TRUE);
 
   if (plugin_foreach(thd, show_handlerton,
-                     MYSQL_STORAGE_ENGINE_PLUGIN, thd->variables.table_type))
+                     MYSQL_STORAGE_ENGINE_PLUGIN, ha_default_handlerton(thd)))
     DBUG_RETURN(TRUE);
 
   send_eof(thd);
@@ -134,24 +134,26 @@ static int make_version_string(char *buf, int buf_length, uint version)
   return my_snprintf(buf, buf_length, "%d.%d", version>>8,version&0xff);
 }
 
-static my_bool show_plugins(THD *thd, st_plugin_int *plugin,
+static my_bool show_plugins(THD *thd, plugin_ref plugin,
                             void *arg)
 {
   TABLE *table= (TABLE*) arg;
-  struct st_mysql_plugin *plug= plugin->plugin;
+  struct st_mysql_plugin *plug= plugin_decl(plugin);
+  struct st_plugin_dl *plugin_dl= plugin_dlib(plugin);
   CHARSET_INFO *cs= system_charset_info;
   char version_buf[20];
 
   restore_record(table, s->default_values);
 
-  table->field[0]->store(plugin->name.str, plugin->name.length, cs);
+  table->field[0]->store(plugin_name(plugin)->str,
+                         plugin_name(plugin)->length, cs);
 
   table->field[1]->store(version_buf,
         make_version_string(version_buf, sizeof(version_buf), plug->version),
         cs);
 
 
-  switch (plugin->state) {
+  switch (plugin_state(plugin)) {
   /* case PLUGIN_IS_FREED: does not happen */
   case PLUGIN_IS_DELETED:
     table->field[2]->store(STRING_WITH_LEN("DELETED"), cs);
@@ -173,14 +175,13 @@ static my_bool show_plugins(THD *thd, st_plugin_int *plugin,
         make_version_string(version_buf, sizeof(version_buf),
                             *(uint *)plug->info), cs);
 
-  if (plugin->plugin_dl)
+  if (plugin_dl)
   {
-    table->field[5]->store(plugin->plugin_dl->dl.str,
-                           plugin->plugin_dl->dl.length, cs);
+    table->field[5]->store(plugin_dl->dl.str, plugin_dl->dl.length, cs);
     table->field[5]->set_notnull();
     table->field[6]->store(version_buf,
           make_version_string(version_buf, sizeof(version_buf),
-                              plugin->plugin_dl->version),
+                              plugin_dl->version),
           cs);
     table->field[6]->set_notnull();
   }
@@ -1236,9 +1237,9 @@ int store_create_info(THD *thd, TABLE_LIST *table_list, String *packet,
     store_key_options(thd, packet, table, key_info);
     if (key_info->parser)
     {
+      LEX_STRING *parser_name= plugin_name(key_info->parser);
       packet->append(STRING_WITH_LEN(" /*!50100 WITH PARSER "));
-      append_identifier(thd, packet, key_info->parser->name.str,
-                        key_info->parser->name.length);
+      append_identifier(thd, packet, parser_name->str, parser_name->length);
       packet->append(STRING_WITH_LEN(" */ "));
     }
   }
@@ -1933,6 +1934,18 @@ void init_status_vars()
   sort_dynamic(&all_status_vars, show_var_cmp);
 }
 
+void reset_status_vars()
+{
+  SHOW_VAR *ptr= (SHOW_VAR*) all_status_vars.buffer;
+  SHOW_VAR *last= ptr + all_status_vars.elements;
+  for (; ptr < last; ptr++)
+  {
+    /* Note that SHOW_LONG_NOFLUSH variables are not reset */
+    if (ptr->type == SHOW_LONG)
+      *(ulong*) ptr->value= 0;
+  }  
+}
+
 /*
   catch-all cleanup function, cleans up everything no matter what
 
@@ -2063,6 +2076,8 @@ static bool show_status_array(THD *thd, const char *wild,
         char *value=var->value;
         const char *pos, *end;                  // We assign a lot of const's
 
+        pthread_mutex_lock(&LOCK_global_system_variables);
+
         if (show_type == SHOW_SYS)
         {
           show_type= ((sys_var*) value)->show_type();
@@ -2145,6 +2160,9 @@ static bool show_status_array(THD *thd, const char *wild,
                                system_charset_info);
         table->field[1]->store(pos, (uint32) (end - pos), system_charset_info);
         table->field[1]->set_notnull();
+
+        pthread_mutex_unlock(&LOCK_global_system_variables);
+
         if (schema_table_store_record(thd, table))
           DBUG_RETURN(TRUE);
       }
@@ -2455,13 +2473,13 @@ struct st_add_schema_table
   const char *wild;
 };
 
-static my_bool add_schema_table(THD *thd, st_plugin_int *plugin,
+static my_bool add_schema_table(THD *thd, plugin_ref plugin,
                                 void* p_data)
 {
   st_add_schema_table *data= (st_add_schema_table *)p_data;
   List<char> *file_list= data->files;
   const char *wild= data->wild;
-  ST_SCHEMA_TABLE *schema_table= (ST_SCHEMA_TABLE *)plugin->data;
+  ST_SCHEMA_TABLE *schema_table= plugin_data(plugin, ST_SCHEMA_TABLE *);
   DBUG_ENTER("add_schema_table");
 
   if (schema_table->hidden)
@@ -2995,7 +3013,7 @@ static int get_schema_tables_record(THD *thd, struct st_table_list *tables,
                   ha_row_type[(uint) share->row_type],
                   NullS);
 #ifdef WITH_PARTITION_STORAGE_ENGINE
-    if (show_table->s->db_type == partition_hton && 
+    if (show_table->s->db_type() == partition_hton && 
         show_table->part_info != NULL && 
         show_table->part_info->no_parts > 0)
       ptr= strmov(ptr, " partitioned");
@@ -3270,19 +3288,20 @@ int fill_schema_charsets(THD *thd, TABLE_LIST *tables, COND *cond)
 }
 
 
-static my_bool iter_schema_engines(THD *thd, st_plugin_int *plugin,
+static my_bool iter_schema_engines(THD *thd, plugin_ref plugin,
                                    void *ptable)
 {
   TABLE *table= (TABLE *) ptable;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   const char *wild= thd->lex->wild ? thd->lex->wild->ptr() : NullS;
   CHARSET_INFO *scs= system_charset_info;
   DBUG_ENTER("iter_schema_engines");
 
   if (!(hton->flags & HTON_HIDDEN))
   {
+    LEX_STRING *name= plugin_name(plugin);
     if (!(wild && wild[0] &&
-          wild_case_compare(scs, plugin->name.str,wild)))
+          wild_case_compare(scs, name->str,wild)))
     {
       LEX_STRING state[2]= {{ C_STRING_WITH_LEN("ENABLED") },
                             { C_STRING_WITH_LEN("DISABLED") }};
@@ -3291,11 +3310,11 @@ static my_bool iter_schema_engines(THD *thd, st_plugin_int *plugin,
       LEX_STRING *tmp;
       restore_record(table, s->default_values);
 
-      table->field[0]->store(plugin->name.str, plugin->name.length, scs);
+      table->field[0]->store(name->str, name->length, scs);
       tmp= &state[test(hton->state)];
       table->field[1]->store(tmp->str, tmp->length, scs);
-      table->field[2]->store(plugin->plugin->descr,
-                             strlen(plugin->plugin->descr), scs);
+      table->field[2]->store(plugin_decl(plugin)->descr,
+                             strlen(plugin_decl(plugin)->descr), scs);
       tmp= &yesno[test(hton->commit)];
       table->field[3]->store(tmp->str, tmp->length, scs);
       tmp= &yesno[test(hton->prepare)];
@@ -4464,10 +4483,10 @@ int fill_variables(THD *thd, TABLE_LIST *tables, COND *cond)
   int res= 0;
   LEX *lex= thd->lex;
   const char *wild= lex->wild ? lex->wild->ptr() : NullS;
-  pthread_mutex_lock(&LOCK_global_system_variables);
-  res= show_status_array(thd, wild, init_vars,
+  rw_rdlock(&LOCK_system_variables_hash);
+  res= show_status_array(thd, wild, enumerate_sys_vars(thd, TRUE),
                          lex->option_type, 0, "", tables->table, 0);
-  pthread_mutex_unlock(&LOCK_global_system_variables);
+  rw_unlock(&LOCK_system_variables_hash);
   DBUG_RETURN(res);
 }
 
@@ -4583,12 +4602,12 @@ struct schema_table_ref
     0	table not found
     1   found the schema table
 */
-static my_bool find_schema_table_in_plugin(THD *thd, st_plugin_int *plugin,
+static my_bool find_schema_table_in_plugin(THD *thd, plugin_ref plugin,
                                            void* p_table)
 {
   schema_table_ref *p_schema_table= (schema_table_ref *)p_table;
   const char* table_name= p_schema_table->table_name;
-  ST_SCHEMA_TABLE *schema_table= (ST_SCHEMA_TABLE *)plugin->data;
+  ST_SCHEMA_TABLE *schema_table= plugin_data(plugin, ST_SCHEMA_TABLE *);
   DBUG_ENTER("find_schema_table_in_plugin");
 
   if (!my_strcasecmp(system_charset_info,
@@ -5125,12 +5144,12 @@ struct run_hton_fill_schema_files_args
   COND *cond;
 };
 
-static my_bool run_hton_fill_schema_files(THD *thd, st_plugin_int *plugin,
+static my_bool run_hton_fill_schema_files(THD *thd, plugin_ref plugin,
                                           void *arg)
 {
   struct run_hton_fill_schema_files_args *args=
     (run_hton_fill_schema_files_args *) arg;
-  handlerton *hton= (handlerton *)plugin->data;
+  handlerton *hton= plugin_data(plugin, handlerton *);
   if(hton->fill_files_table && hton->state == SHOW_OPTION_YES)
     hton->fill_files_table(hton, thd, args->tables, args->cond);
   return false;
@@ -5296,10 +5315,10 @@ int fill_schema_global_variables(THD *thd, TABLE_LIST *tables, COND *cond)
   int res= 0;
   DBUG_ENTER("fill_schema_global_variables");
   
-  pthread_mutex_lock(&LOCK_global_system_variables);
-  res= show_status_array(thd, "", init_vars, OPT_GLOBAL,
+  rw_rdlock(&LOCK_system_variables_hash);
+  res= show_status_array(thd, "", enumerate_sys_vars(thd, FALSE), OPT_GLOBAL,
                          NULL, "", tables->table, 1);
-  pthread_mutex_unlock(&LOCK_global_system_variables);
+  rw_unlock(&LOCK_system_variables_hash);
   
   DBUG_RETURN(res);
 }
@@ -5309,10 +5328,10 @@ int fill_schema_session_variables(THD *thd, TABLE_LIST *tables, COND *cond)
   int res= 0;
   DBUG_ENTER("fill_schema_session_variables");
   
-  pthread_mutex_lock(&LOCK_global_system_variables);
-  res= show_status_array(thd, "", init_vars, OPT_SESSION,
+  rw_rdlock(&LOCK_system_variables_hash);
+  res= show_status_array(thd, "", enumerate_sys_vars(thd, FALSE), OPT_SESSION,
                          NULL, "", tables->table, 1);
-  pthread_mutex_unlock(&LOCK_global_system_variables);
+  rw_unlock(&LOCK_system_variables_hash);
   
   DBUG_RETURN(res);
 }
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 36f0acd8f67..5998423790b 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -662,16 +662,14 @@ static int execute_ddl_log_action(THD *thd, DDL_LOG_ENTRY *ddl_log_entry)
     frm_action= TRUE;
   else
   {
-    TABLE_SHARE dummy;
-
-    hton= ha_resolve_by_name(thd, &handler_name);
-    if (!hton)
+    plugin_ref plugin= ha_resolve_by_name(thd, &handler_name);
+    if (!plugin)
     {
       my_error(ER_ILLEGAL_HA, MYF(0), ddl_log_entry->handler_name);
       goto error;
     }
-    bzero(&dummy, sizeof(TABLE_SHARE));
-    file= get_new_handler(&dummy, &mem_root, hton);
+    hton= plugin_data(plugin, handlerton*);
+    file= get_new_handler((TABLE_SHARE*)0, &mem_root, hton);
     if (!file)
     {
       mem_alloc_error(sizeof(handler));
@@ -1635,7 +1633,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     TABLE_SHARE *share;
     table->db_type= NULL;
     if ((share= get_cached_table_share(table->db, table->table_name)))
-      table->db_type= share->db_type;
+      table->db_type= share->db_type();
 
     /* Disable drop of enabled log tables */
     if (share && share->log_table &&
@@ -5031,7 +5029,7 @@ static uint compare_tables(TABLE *table, List<create_field> *create_list,
     See BUG#6236.
   */
   if (table->s->fields != create_list->elements ||
-      table->s->db_type != create_info->db_type ||
+      table->s->db_type() != create_info->db_type ||
       table->s->tmp_table ||
       create_info->used_fields & HA_CREATE_USED_ENGINE ||
       create_info->used_fields & HA_CREATE_USED_CHARSET ||
@@ -5490,7 +5488,7 @@ view_err:
     new_name= table_name;
   }
 
-  old_db_type= table->s->db_type;
+  old_db_type= table->s->db_type();
   if (!create_info->db_type)
   {
 #ifdef WITH_PARTITION_STORAGE_ENGINE
@@ -6002,7 +6000,7 @@ view_err:
   }
 
   if (thd->variables.old_alter_table
-      || (table->s->db_type != create_info->db_type)
+      || (table->s->db_type() != create_info->db_type)
 #ifdef WITH_PARTITION_STORAGE_ENGINE
       || partition_changed
 #endif
@@ -6040,8 +6038,8 @@ view_err:
     uint  *idx_p;
     uint  *idx_end_p;
 
-    if (table->s->db_type->alter_table_flags)
-      alter_flags= table->s->db_type->alter_table_flags(alter_info->flags);
+    if (table->s->db_type()->alter_table_flags)
+      alter_flags= table->s->db_type()->alter_table_flags(alter_info->flags);
     DBUG_PRINT("info", ("alter_flags: %lu", alter_flags));
     /* Check dropped indexes. */
     for (idx_p= index_drop_buffer, idx_end_p= idx_p + index_drop_count;
@@ -7066,7 +7064,7 @@ static bool check_engine(THD *thd, const char *table_name,
     if (create_info->used_fields & HA_CREATE_USED_ENGINE)
     {
       my_error(ER_ILLEGAL_HA_CREATE_OPTION, MYF(0),
-               hton2plugin[(*new_engine)->slot]->name.str, "TEMPORARY");
+               ha_resolve_storage_engine_name(*new_engine), "TEMPORARY");
       *new_engine= 0;
       return TRUE;
     }
diff --git a/sql/sql_tablespace.cc b/sql/sql_tablespace.cc
index 84391a54642..b4a03a370ba 100644
--- a/sql/sql_tablespace.cc
+++ b/sql/sql_tablespace.cc
@@ -34,7 +34,7 @@ int mysql_alter_tablespace(THD *thd, st_alter_tablespace *ts_info)
       push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                           ER_WARN_USING_OTHER_HANDLER,
                           ER(ER_WARN_USING_OTHER_HANDLER),
-                          hton2plugin[hton->slot]->name.str,
+                          ha_resolve_storage_engine_name(hton),
                           ts_info->tablespace_name ? ts_info->tablespace_name
                                                 : ts_info->logfile_group_name);
   }
@@ -63,7 +63,7 @@ int mysql_alter_tablespace(THD *thd, st_alter_tablespace *ts_info)
     push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                         ER_ILLEGAL_HA_CREATE_OPTION,
                         ER(ER_ILLEGAL_HA_CREATE_OPTION),
-                        hton2plugin[hton->slot]->name.str,
+                        ha_resolve_storage_engine_name(hton),
                         "TABLESPACE or LOGFILE GROUP");
   }
   if (mysql_bin_log.is_open())
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 9c062407921..b9eb9d9ffc9 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -1043,7 +1043,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 
 %type <interval_time_st> interval_time_st
 
-%type <db_type> storage_engines
+%type <db_type> storage_engines known_storage_engine
 
 %type <row_type> row_types
 
@@ -1447,14 +1447,26 @@ create:
 	  lex->change=NullS;
 	  bzero((char*) &lex->create_info,sizeof(lex->create_info));
 	  lex->create_info.options=$2 | $4;
-	  lex->create_info.db_type= lex->thd->variables.table_type;
+	  lex->create_info.db_type= ha_default_handlerton(thd);
 	  lex->create_info.default_table_charset= NULL;
 	  lex->name.str= 0;
           lex->name.length= 0;
          lex->like_name= 0;
 	}
 	create2
-	  { Lex->current_select= &Lex->select_lex; }
+	{
+	  LEX *lex= YYTHD->lex;
+          lex->current_select= &lex->select_lex; 
+          if (!lex->create_info.db_type)
+          {
+            lex->create_info.db_type= ha_default_handlerton(YYTHD);
+            push_warning_printf(YYTHD, MYSQL_ERROR::WARN_LEVEL_WARN,
+                                ER_WARN_USING_OTHER_HANDLER,
+                                ER(ER_WARN_USING_OTHER_HANDLER),
+                                ha_resolve_storage_engine_name(lex->create_info.db_type),
+                                $5->table.str);
+          }
+        }
 	| CREATE opt_unique_or_fulltext INDEX_SYM ident key_alg ON
 	  table_ident
 	  {
@@ -3365,7 +3377,7 @@ opt_ts_comment:
           };
 
 opt_ts_engine:
-          opt_storage ENGINE_SYM opt_equal storage_engines
+          opt_storage ENGINE_SYM opt_equal known_storage_engine
           {
             LEX *lex= Lex;
             if (lex->alter_tablespace_info->storage_engine != NULL)
@@ -3533,6 +3545,13 @@ partitioning:
         {
 #ifdef WITH_PARTITION_STORAGE_ENGINE
           LEX *lex= Lex;
+          LEX_STRING partition_name={C_STRING_WITH_LEN("partition")};
+          if (!plugin_is_ready(&partition_name, MYSQL_STORAGE_ENGINE_PLUGIN))
+          {
+            my_error(ER_FEATURE_DISABLED, MYF(0),
+                     "partitioning", "--with-partition");
+            YYABORT;
+          }
           lex->part_info= new partition_info();
           if (!lex->part_info)
           {
@@ -4046,7 +4065,7 @@ opt_part_option_list:
 opt_part_option:
         TABLESPACE opt_equal ident_or_text
         { Lex->part_info->curr_part_elem->tablespace_name= $3.str; }
-        | opt_storage ENGINE_SYM opt_equal storage_engines
+        | opt_storage ENGINE_SYM opt_equal known_storage_engine
         {
           LEX *lex= Lex;
           lex->part_info->curr_part_elem->engine_type= $4;
@@ -4251,21 +4270,43 @@ default_collation:
 storage_engines:
 	ident_or_text
 	{
-	  $$ = ha_resolve_by_name(YYTHD, &$1);
-	  if ($$ == NULL)
+          LEX *lex= YYTHD->lex;
+          plugin_ref plugin;
+          
+          if ((plugin= ha_resolve_by_name(YYTHD, &$1)))
+            $$= plugin_data(plugin, handlerton*);
+          else
           if (YYTHD->variables.sql_mode & MODE_NO_ENGINE_SUBSTITUTION)
 	  {
 	    my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(0), $1.str);
 	    YYABORT;
 	  }
           else
+          if (lex->sql_command == SQLCOM_ALTER_TABLE)
           {
-            push_warning_printf(YYTHD, MYSQL_ERROR::WARN_LEVEL_ERROR,
-                                ER_UNKNOWN_STORAGE_ENGINE,
-                                ER(ER_UNKNOWN_STORAGE_ENGINE), $1.str);
+            TABLE_LIST *table= (TABLE_LIST *) lex->select_lex.table_list.first;
+            $$= ha_default_handlerton(YYTHD);
+            push_warning_printf(YYTHD, MYSQL_ERROR::WARN_LEVEL_WARN,
+                                ER_WARN_USING_OTHER_HANDLER,
+                                ER(ER_WARN_USING_OTHER_HANDLER),
+                                ha_resolve_storage_engine_name($$),
+                                table->table_name);
           }
 	};
 
+known_storage_engine:
+	ident_or_text
+	{
+          plugin_ref plugin;
+          if ((plugin= ha_resolve_by_name(YYTHD, &$1)))
+            $$= plugin_data(plugin, handlerton*);
+          else
+	  {
+	    my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(0), $1.str);
+	    YYABORT;
+	  }
+	};
+
 row_types:
 	DEFAULT		{ $$= ROW_TYPE_DEFAULT; }
 	| FIXED_SYM	{ $$= ROW_TYPE_FIXED; }
@@ -8452,7 +8493,7 @@ show_param:
             if (prepare_schema_table(YYTHD, lex, 0, SCH_PLUGINS))
               YYABORT;
 	  }
-	| ENGINE_SYM storage_engines 
+	| ENGINE_SYM known_storage_engine
 	  { Lex->create_info.db_type= $2; }
 	  show_engine_param
 	| ENGINE_SYM ALL 
@@ -10095,7 +10136,7 @@ sys_option_value:
 	  LEX *lex=Lex;
 	  lex->option_type= $1;
 	  lex->var_list.push_back(new set_var(lex->option_type,
-                                              find_sys_var("tx_isolation"),
+                                              find_sys_var(YYTHD, "tx_isolation"),
                                               &null_lex_str,
                                               new Item_int((int32) $5)));
 	}
@@ -10184,7 +10225,7 @@ internal_variable_name:
 	  if (!spc || !(spv = spc->find_variable(&$1)))
 	  {
             /* Not an SP local variable */
-	    sys_var *tmp=find_sys_var($1.str, $1.length);
+	    sys_var *tmp=find_sys_var(YYTHD, $1.str, $1.length);
 	    if (!tmp)
 	      YYABORT;
 	    $$.var= tmp;
@@ -10246,7 +10287,7 @@ internal_variable_name:
             }
             else
             {
-              sys_var *tmp=find_sys_var($3.str, $3.length);
+              sys_var *tmp=find_sys_var(YYTHD, $3.str, $3.length);
               if (!tmp)
                 YYABORT;
               if (!tmp->is_struct())
@@ -10257,7 +10298,7 @@ internal_variable_name:
 	  }
 	| DEFAULT '.' ident
 	  {
-	    sys_var *tmp=find_sys_var($3.str, $3.length);
+	    sys_var *tmp=find_sys_var(YYTHD, $3.str, $3.length);
 	    if (!tmp)
 	      YYABORT;
 	    if (!tmp->is_struct())
diff --git a/sql/structs.h b/sql/structs.h
index 377d337dcfa..3c08b5a3de1 100644
--- a/sql/structs.h
+++ b/sql/structs.h
@@ -83,7 +83,11 @@ typedef struct st_key {
   */
   union
   {
+#ifdef DBUG_OFF
     struct st_plugin_int *parser;       /* Fulltext [pre]parser */
+#else
+    struct st_plugin_int **parser;      /* Fulltext [pre]parser */
+#endif
     LEX_STRING *parser_name;            /* Fulltext [pre]parser name */
   };
   KEY_PART_INFO *key_part;
diff --git a/sql/table.cc b/sql/table.cc
index ed3cac85214..08acaa0304f 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -238,6 +238,9 @@ void free_table_share(TABLE_SHARE *share)
     pthread_cond_destroy(&share->cond);
   }
   hash_free(&share->name_hash);
+  
+  plugin_unlock(NULL, share->db_plugin);
+  share->db_plugin= NULL;
 
   /* We must copy mem_root from share because share is allocated through it */
   memcpy((char*) &mem_root, (char*) &share->mem_root, sizeof(mem_root));
@@ -422,6 +425,7 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
   Field  **field_ptr, *reg_field;
   const char **interval_array;
   enum legacy_db_type legacy_db_type;
+  handlerton *hton;
   my_bitmap_map *bitmaps;
   DBUG_ENTER("open_binary_frm");
 
@@ -452,7 +456,11 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
   DBUG_PRINT("info", ("default_part_db_type = %u", head[61]));
 #endif
   legacy_db_type= (enum legacy_db_type) (uint) *(head+3);
-  share->db_type= ha_checktype(thd, legacy_db_type, 0, 0);
+  if ((hton= ha_checktype(thd, legacy_db_type, 0, 0)) != share->db_type())
+  {
+    plugin_unlock(NULL, share->db_plugin);
+    share->db_plugin= ha_lock_engine(NULL, hton);
+  }
   share->db_create_options= db_create_options= uint2korr(head+30);
   share->db_options_in_use= share->db_create_options;
   share->mysql_version= uint4korr(head+51);
@@ -611,24 +619,38 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
     {
       uint str_db_type_length= uint2korr(next_chunk);
       LEX_STRING name= { next_chunk + 2, str_db_type_length };
-      handlerton *tmp_db_type= ha_resolve_by_name(thd, &name);
-      if (tmp_db_type != NULL)
+      plugin_ref tmp_plugin= ha_resolve_by_name(thd, &name);
+      if (tmp_plugin != NULL)
       {
-        share->db_type= tmp_db_type;
+        /*
+          tmp_plugin is locked with a local lock.
+          we unlock the old value of share->db_plugin before
+          replacing it with a globally locked version of tmp_plugin
+        */
+        plugin_unlock(NULL, share->db_plugin);
+        share->db_plugin= my_plugin_lock(NULL, &tmp_plugin);
         DBUG_PRINT("info", ("setting dbtype to '%.*s' (%d)",
                             str_db_type_length, next_chunk + 2,
-                            ha_legacy_type(share->db_type)));
+                            ha_legacy_type(share->db_type())));
       }
 #ifdef WITH_PARTITION_STORAGE_ENGINE
       else
       {
-        if (!strncmp(next_chunk + 2, "partition", str_db_type_length))
+        LEX_STRING pname= { C_STRING_WITH_LEN( "partition" ) };
+        if (str_db_type_length == pname.length &&
+            !strncmp(next_chunk + 2, pname.str, pname.length))
         {
-          /* Use partition handler */
-          share->db_type= partition_hton;
+          /*
+            Use partition handler
+            tmp_plugin is locked with a local lock.
+            we unlock the old value of share->db_plugin before
+            replacing it with a globally locked version of tmp_plugin
+          */
+          plugin_unlock(NULL, share->db_plugin);
+          share->db_plugin= ha_lock_engine(NULL, partition_hton);
           DBUG_PRINT("info", ("setting dbtype to '%.*s' (%d)",
                               str_db_type_length, next_chunk + 2,
-                              ha_legacy_type(share->db_type)));
+                              ha_legacy_type(share->db_type())));
         }
       }
 #endif
@@ -694,7 +716,8 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
         }
         parser_name.str= next_chunk;
         parser_name.length= strlen(next_chunk);
-        keyinfo->parser= plugin_lock(&parser_name, MYSQL_FTPARSER_PLUGIN);
+        keyinfo->parser= my_plugin_lock_by_name(NULL, &parser_name,
+                                                MYSQL_FTPARSER_PLUGIN);
         if (! keyinfo->parser)
         {
           my_error(ER_PLUGIN_IS_NOT_LOADED, MYF(0), parser_name.str);
@@ -810,7 +833,7 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
 
  /* Allocate handler */
   if (!(handler_file= get_new_handler(share, thd->mem_root,
-                                      share->db_type)))
+                                      share->db_type())))
     goto err;
 
   record= (char*) share->default_values-1;	/* Fieldstart = 1 */
@@ -1344,7 +1367,7 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
 
   /* Allocate handler */
   if (!(outparam->file= get_new_handler(share, &outparam->mem_root,
-                                        share->db_type)))
+                                        share->db_type())))
     goto err;
 
   error= 4;
@@ -1628,7 +1651,7 @@ int closefrm(register TABLE *table, bool free_share)
   {
     if (key_info->flags & HA_USES_PARSER)
     {
-      plugin_unlock(key_info->parser);
+      plugin_unlock(NULL, key_info->parser);
       key_info->flags= 0;
     }
   }
@@ -1839,10 +1862,10 @@ void open_table_error(TABLE_SHARE *share, int error, int db_errno, int errarg)
     handler *file= 0;
     const char *datext= "";
     
-    if (share->db_type != NULL)
+    if (share->db_type() != NULL)
     {
       if ((file= get_new_handler(share, current_thd->mem_root,
-                                 share->db_type)))
+                                 share->db_type())))
       {
         if (!(datext= *file->bas_ext()))
           datext= "";
diff --git a/sql/table.h b/sql/table.h
index fc2f25f3aa8..6dba46a535e 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -172,7 +172,12 @@ typedef struct st_table_share
   ulong   timestamp_offset;		/* Set to offset+1 of record */
   ulong   reclength;			/* Recordlength */
 
-  handlerton *db_type;			/* table_type for handler */
+  plugin_ref db_plugin;			/* storage engine plugin */
+  inline handlerton *db_type() const	/* table_type for handler */
+  { 
+    // DBUG_ASSERT(db_plugin);
+    return db_plugin ? plugin_data(db_plugin, handlerton*) : NULL;
+  }
   enum row_type row_type;		/* How rows are stored */
   enum tmp_table_type tmp_table;
author	unknown <antony@ppcg5.local>	2007-03-02 08:43:45 -0800
committer	unknown <antony@ppcg5.local>	2007-03-02 08:43:45 -0800
commit	1fc7f2117bddfcf91e1220f22714beb86d26c544 (patch)
tree	23fe49e9ab83f6badb4e173587f9e194490a3859 /sql
parent	1eb71c68cb1b2f335a8e6b393cdb3e724ea65a0a (diff)
download	mariadb-git-1fc7f2117bddfcf91e1220f22714beb86d26c544.tar.gz