Merge bk-internal.mysql.com:/home/bk/mysql-5.1

into  sergbook.mysql.com:/usr/home/serg/Abk/mysql-5.1-wl2936


client/mysql.cc:
  Auto merged
include/my_global.h:
  Auto merged
include/my_sys.h:
  Auto merged
include/mysql.h:
  Auto merged
mysql-test/r/im_utils.result:
  Auto merged
mysql-test/r/variables.result:
  Auto merged
mysql-test/t/ndb_dd_basic.test:
  Auto merged
mysql-test/t/partition_innodb.test:
  Auto merged
mysql-test/t/variables.test:
  Auto merged
mysys/array.c:
  Auto merged
mysys/typelib.c:
  Auto merged
sql/event_queue.cc:
  Auto merged
sql/ha_partition.cc:
  Auto merged
sql/ha_partition.h:
  Auto merged
sql/handler.cc:
  Auto merged
sql/handler.h:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_sum.cc:
  Auto merged
sql/log.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/set_var.h:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_cache.cc:
  Auto merged
sql/sql_class.h:
  Auto merged
sql/sql_delete.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged
sql/sql_lex.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_partition.cc:
  Auto merged
sql/sql_plugin.cc:
  Auto merged
sql/sql_repl.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/sql_show.cc:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/table.cc:
  Auto merged
sql/table.h:
  Auto merged
storage/example/ha_example.cc:
  Auto merged
storage/federated/ha_federated.cc:
  Auto merged
storage/heap/ha_heap.cc:
  Auto merged
storage/innobase/include/trx0trx.h:
  Auto merged
storage/myisam/ha_myisam.cc:
  Auto merged
storage/myisammrg/ha_myisammrg.cc:
  Auto merged
storage/ndb/src/mgmsrv/InitConfigFileParser.cpp:
  Auto merged
include/typelib.h:
  merged
mysql-test/mysql-test-run.pl:
  merged
mysql-test/r/flush2.result:
  merged
mysql-test/r/ndb_dd_basic.result:
  merged
mysql-test/r/partition_innodb.result:
  merged
mysql-test/r/ps_1general.result:
  merged
mysql-test/t/ps_1general.test:
  merged
sql/ha_ndbcluster.cc:
  merged
sql/item_create.cc:
  merged
sql/mysqld.cc:
  merged
sql/rpl_utility.h:
  merged
sql/set_var.cc:
  merged
sql/sql_class.cc:
  merged
sql/sql_yacc.yy:
  merged
storage/innobase/handler/ha_innodb.cc:
  merged
storage/innobase/handler/ha_innodb.h:
  merged

1 files changed, 203 insertions, 188 deletions

diff --git a/sql/set_var.h b/sql/set_var.h
index a3963171192..5ec7eb7ef4a 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, const 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);
@@ -187,14 +197,14 @@ 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)
   {
@@ -219,9 +229,9 @@ 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;
@@ -248,9 +258,9 @@ 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;
@@ -278,10 +288,10 @@ 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);
@@ -296,7 +306,8 @@ 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; }
@@ -312,13 +323,13 @@ 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);
@@ -331,13 +342,15 @@ 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; }
@@ -350,14 +363,16 @@ 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; }
@@ -377,13 +392,13 @@ 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; }
@@ -403,23 +418,23 @@ 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;
@@ -440,8 +455,9 @@ 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)
@@ -458,11 +474,12 @@ 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)
@@ -477,8 +494,9 @@ 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);
@@ -492,12 +510,12 @@ 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; }
@@ -509,7 +527,9 @@ 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; }
@@ -525,7 +545,9 @@ 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; }
@@ -538,7 +560,9 @@ 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; }
@@ -549,7 +573,9 @@ 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; }
@@ -557,33 +583,12 @@ 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; }
 };
@@ -591,7 +596,9 @@ 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; }
 };
@@ -600,7 +607,8 @@ 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;
     }
@@ -618,10 +626,9 @@ 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.
@@ -641,83 +648,47 @@ 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 *SV::*offset;
+  CHARSET_INFO **global_default;
 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 *SV::*offset;
+  CHARSET_INFO **global_default;
 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);
@@ -729,9 +700,10 @@ 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; }
@@ -741,8 +713,9 @@ 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; }
@@ -752,8 +725,8 @@ 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; }
@@ -765,12 +738,12 @@ 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)
   {
@@ -789,8 +762,9 @@ 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);
 };
@@ -801,10 +775,10 @@ 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);
@@ -825,12 +799,12 @@ 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; }
@@ -844,19 +818,17 @@ 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; }
@@ -867,13 +839,47 @@ 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; }
@@ -891,8 +897,9 @@ 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)
@@ -908,8 +915,9 @@ 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);
@@ -923,8 +931,9 @@ 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);
 };
@@ -933,12 +942,13 @@ 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; }
@@ -957,8 +967,8 @@ 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; }
@@ -974,8 +984,9 @@ 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
                       )
@@ -1013,7 +1024,7 @@ 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;
@@ -1142,9 +1153,13 @@ 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);