Implementation of Multi-source replication (MDEV:253)

Documentation of the feature can be found at: http://kb.askmonty.org/en/multi-source-replication/
This code is based on code from Taobao, developed by Plinux

BUILD/SETUP.sh:
  Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
client/mysqltest.cc:
  Added support for error names starting with 'W'
  Added connection_name support to --sync_with_master
cmake/maintainer.cmake:
  Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
mysql-test/r/mysqltest.result:
  Updated results
mysql-test/r/parser.result:
  Updated results
mysql-test/suite/multi_source/my.cnf:
  Setup of multi-master tests
mysql-test/suite/multi_source/simple.result:
  Simple basic test of multi-source functionality
mysql-test/suite/multi_source/simple.test:
  Simple basic test of multi-source functionality
mysql-test/suite/multi_source/syntax.result:
  Test of multi-source syntax
mysql-test/suite/multi_source/syntax.test:
  Test of multi-source syntax
mysql-test/suite/rpl/r/rpl_rotate_logs.result:
  Updated results because of new error messages
mysql-test/t/parser.test:
  Updated test as master_pos_wait() now takes more arguments than before
sql/event_scheduler.cc:
  No reason to initialize slave_thread (it's guaranteed to be zero here)
sql/item_create.cc:
  Added connection_name argument to master_pos_wait()
  Simplified code
sql/item_func.cc:
  Added connection_name argument to master_pos_wait()
sql/item_func.h:
  Added connection_name argument to master_pos_wait()
sql/log.cc:
  Added tag "Master 'connection_name'" to slave errors that has a connection name.
sql/mysqld.cc:
  Added variable mysqld_server_initialized so that other functions can test if server is fully initialized.
  Free all slave data in one place (fewer ifdef's)
  Removed not needed call to close_active_mi()
  Initialize slaves() later in startup to ensure that everthing is really initialized when slaves start.
  Made status variable slave_running multi-source safe
sql/mysqld.h:
  Added mysqld_server_initialized
sql/rpl_mi.cc:
  Store connection name and cmp_connection_name (only used for show full slave status) in Master_info
  Added code for Master_info_index, which handles storage of multi-master information
  Don't write the empty "" connection_name to multi-master.info file. This is handled by the original code.
sql/rpl_mi.h:
  Added connection_name and Master_info_index
sql/rpl_rli.cc:
  Added connection_name to relay log files.
sql/rpl_rli.h:
  Fixed type of slave_skip_counter as we now access it directly in sys_vars.cc, so it must be uint
sql/share/errmsg-utf8.txt:
  Added new error messages needed for multi-source
  Added multi-source name to error ER_MASTER_INFO and WARN_NO_MASTER_INFO
sql/slave.cc:
  Moved things a bit around to make it easier to handle error conditions.
  Create a global master_info_index and add the "" connection to it
  Ensure that new Master_info doesn't fail.
  Don't call terminate_slave_threads(active_mi..) on end_slave() as this is now done automaticly when deleting master_info_index.
  Delete not needed function close_active_mi(). One can achive same thing by calling end_slave().
  Added support for SHOW FULL SLAVE STATUS (show status for all master connections with connection_name as first column)
sql/slave.h:
  Added new prototypes
sql/sql_base.cc:
  More DBUG_PRINT
sql/sql_class.cc:
  Reset thd->connection_name and thd-->default_master_connection
sql/sql_class.h:
  Added thd->connection_name and thd-->default_master_connection
  Added slave_skip_count to variables to make changing the @@sql_slave_skip_count variable thread safe
sql/sql_const.h:
  Added MAX_CONNECTION_NAME
sql/sql_lex.cc:
  Reset 'lex->verbose' (to simplify some sql_yacc.yy code)
sql/sql_lex.h:
  Added connection_name
sql/sql_parse.cc:
  Added support for connection_name to all SLAVE commands.
  - Instead of using active_mi, we now get the current Master_info from master_info_index.
  - Create new replication threads with CHANGE MASTER
  - Added support for show_all_master_info()
sql/sql_reload.cc:
  Made reset/full slave use master_info_index->get_master_info() instead of active_mi.
  If one uses 'RESET SLAVE "connection_name" all' the connection is removed from master_info_index.
sql/sql_repl.cc:
  sql_slave_skip_counter is moved to thd->variables to make it thread safe and fix some bugs with it
  Add connection name to relay log files.
  Added connection name to errors.
  Added some logging for multi-master if log_warnings > 1
  stop_slave():
  - Don't check if thd is set. It's guaranteed to always be set.
  change_master():
  - Check for duplicate connection names in change_master()
  - Check for wrong arguments first in file (to simplify error handling)
  - Register new connections in master_info_index
sql/sql_yacc.yy:
  Added optional connection_name to a all relevant master/slave commands
sql/strfunc.cc:
  my_global.h shoud always be included first.
sql/sys_vars.cc:
  Added variable default_master_connection
  Made variable sql_slave_skip_counter multi-source safe
sql/sys_vars.h:
  Added Sys_var_session_lexstring (needed for default_master_connection)
  Added Sys_var_multi_source_uint (needed for sql_slave_skip_counter).

1 files changed, 142 insertions, 0 deletions

diff --git a/sql/sys_vars.h b/sql/sys_vars.h
index 21bebcd762c..6509ba6a5f4 100644
--- a/sql/sys_vars.h
+++ b/sql/sys_vars.h
@@ -633,6 +633,88 @@ public:
   }
 };
 
+
+/*
+  A LEX_STRING stored only in thd->variables
+  Only to be used for small buffers
+*/
+
+class Sys_var_session_lexstring: public sys_var
+{
+  size_t max_length;
+public:
+  Sys_var_session_lexstring(const char *name_arg,
+                            const char *comment, int flag_args,
+                            ptrdiff_t off, size_t size, CMD_LINE getopt,
+                            enum charset_enum is_os_charset_arg,
+                            const char *def_val, size_t max_length_arg,
+                            on_check_function on_check_func=0,
+                            on_update_function on_update_func=0)
+    : sys_var(&all_sys_vars, name_arg, comment, flag_args, off, getopt.id,
+              getopt.arg_type, SHOW_CHAR, (intptr)def_val,
+              0, VARIABLE_NOT_IN_BINLOG, on_check_func, on_update_func,
+              0, 0),max_length(max_length_arg)
+  {
+    option.var_type= GET_NO_ARG;
+    SYSVAR_ASSERT(scope() == ONLY_SESSION)
+    *const_cast<SHOW_TYPE*>(&show_val_type)= SHOW_LEX_STRING;
+  }
+  bool do_check(THD *thd, set_var *var)
+  {
+    char buff[STRING_BUFFER_USUAL_SIZE];
+    String str(buff, sizeof(buff), system_charset_info), *res;
+
+    if (!(res=var->value->val_str(&str)))
+      var->save_result.string_value.str= const_cast<char*>("");
+    else
+    {
+      if (res->length() > max_length)
+      {
+        my_error(ER_WRONG_STRING_LENGTH, MYF(0),
+                 res->ptr(), name.str, (int) max_length);
+        return true;
+      }
+      var->save_result.string_value.str= thd->strmake(res->ptr(),
+                                                      res->length());
+      var->save_result.string_value.length= res->length();
+    }
+    return false;
+  }
+  bool session_update(THD *thd, set_var *var)
+  {
+    LEX_STRING *tmp= &session_var(thd, LEX_STRING);
+    tmp->length= var->save_result.string_value.length;
+    /* Store as \0 terminated string (just to be safe) */
+    strmake(tmp->str, var->save_result.string_value.str, tmp->length);
+    return false;
+  }
+  bool global_update(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(FALSE);
+    return false;
+  }
+  void session_save_default(THD *thd, set_var *var)
+  {
+    char *ptr= (char*)(intptr)option.def_value;
+    var->save_result.string_value.str= ptr;
+  }
+  void global_save_default(THD *thd, set_var *var)
+  {
+    DBUG_ASSERT(FALSE);
+  }
+  uchar *session_value_ptr(THD *thd, LEX_STRING *base)
+  {
+    return (uchar*) &session_var(thd, LEX_STRING);
+  }
+  uchar *global_value_ptr(THD *thd, LEX_STRING *base)
+  {
+    DBUG_ASSERT(FALSE);
+  }
+  bool check_update_type(Item_result type)
+  { return type != STRING_RESULT; }
+};
+
+
 #ifndef DBUG_OFF
 /**
   @@session.dbug and @@global.dbug variables.
@@ -1389,6 +1471,7 @@ public:
 };
 #endif /* defined(ENABLED_DEBUG_SYNC) */
 
+
 /**
   The class for bit variables - a variant of boolean that stores the value
   in a bit.
@@ -1862,6 +1945,65 @@ public:
   bool global_update(THD *thd, set_var *var);
 };
 
+/*
+  Class for handing multi-source replication variables
+  Variable values are store in Master_info, but to make it possible to
+  access variable without locks we also store it thd->variables.
+  These can be used as GLOBAL or SESSION, but both points to the same
+  variable.  This is to make things compatible with MySQL 5.5 where variables
+  like sql_slave_skip_counter are GLOBAL.
+*/
+
+class Sys_var_multi_source_uint :public Sys_var_uint
+{ 
+  ptrdiff_t master_info_offset;
+public:
+  Sys_var_multi_source_uint(const char *name_arg,
+                            const char *comment, int flag_args,
+                            ptrdiff_t off, size_t size,
+                            ptrdiff_t master_info_offset_arg,
+                            uint min_val, uint max_val, uint def_val,
+                            uint block_size,
+                            on_update_function on_update_func)
+    :Sys_var_uint(name_arg, comment, flag_args, off, size,
+                  NO_CMD_LINE, min_val, max_val, def_val, block_size,
+                  0, VARIABLE_NOT_IN_BINLOG, 0, on_update_func),
+    master_info_offset(master_info_offset_arg)
+  {
+    /* No global storage of variables. Cause a crash if we try an update */
+    option.value= (uchar**)1;
+  }
+  bool session_update(THD *thd, set_var *var)
+  {
+    session_var(thd, uint)= (uint) (var->save_result.ulonglong_value);
+    /* Value should be moved to multi_master in on_update_func */
+    return false;
+  }
+  bool global_update(THD *thd, set_var *var)
+  {
+    return session_update(thd, var);
+  }
+  void session_save_default(THD *thd, set_var *var)
+  {
+    /* Use value given in variable declaration */
+    global_save_default(thd, var);
+  }
+  uchar *session_value_ptr(THD *thd,LEX_STRING *base)
+  {
+    uint *tmp, res;
+    tmp= (uint*) (((uchar*)&(thd->variables)) + offset);
+    res= get_master_info_uint_value(thd, master_info_offset);
+    *tmp= res;
+    return (uchar*) tmp;
+  }
+  uchar *global_value_ptr(THD *thd, LEX_STRING *base)
+  {
+    return session_value_ptr(thd, base);
+  }
+  uint get_master_info_uint_value(THD *thd, ptrdiff_t offset);
+};
+
+
 /****************************************************************************
   Used templates
 ****************************************************************************/