Backporting WL#4398 WL#1720

Backporting BUG#44058 BUG#42244 BUG#45672 BUG#45673
Backporting BUG#45819 BUG#45973 BUG#39012

.bzr-mysql/default.conf

 [MYSQL]
 post_commit_to = "commits@lists.mysql.com"
 post_push_to = "commits@lists.mysql.com"
-tree_name = "mysql-5.1"
+tree_name = "mysql-5.1-rep-semisync"

include/mysql/plugin.h

@@ -16,6 +16,11 @@
 #ifndef _my_plugin_h
 #define _my_plugin_h
 
+/* size_t */
+#include <stdlib.h>
+
+typedef struct st_mysql MYSQL;
+
 
 /*
   On Windows, exports from DLL need to be declared
@@ -75,7 +80,8 @@ typedef struct st_mysql_xid MYSQL_XID;
 #define MYSQL_FTPARSER_PLUGIN        2  /* Full-text parser plugin      */
 #define MYSQL_DAEMON_PLUGIN          3  /* The daemon/raw plugin type */
 #define MYSQL_INFORMATION_SCHEMA_PLUGIN  4  /* The I_S plugin type */
-#define MYSQL_MAX_PLUGIN_TYPE_NUM    5  /* The number of plugin types   */
+#define MYSQL_REPLICATION_PLUGIN     5	/* The replication plugin type */
+#define MYSQL_MAX_PLUGIN_TYPE_NUM    6  /* The number of plugin types   */
 
 /* We use the following strings to define licenses for plugins */
 #define PLUGIN_LICENSE_PROPRIETARY 0
@@ -650,6 +656,17 @@ struct st_mysql_information_schema
   int interface_version;
 };
 
+/*
+  API for Replication plugin. (MYSQL_REPLICATION_PLUGIN)
+*/
+ #define MYSQL_REPLICATION_INTERFACE_VERSION 0x0100
+ 
+ /**
+    Replication plugin descriptor
+ */
+ struct Mysql_replication {
+   int interface_version;
+ };
 
 /*
   st_mysql_value struct for reading values from mysqld.
@@ -801,6 +818,64 @@ void mysql_query_cache_invalidate4(MYSQL_THD thd,
                                    const char *key, unsigned int key_length,
                                    int using_trx);
 
+/**
+   Get the value of user variable as an integer.
+
+   This function will return the value of variable @a name as an
+   integer. If the original value of the variable is not an integer,
+   the value will be converted into an integer.
+
+   @param name     user variable name
+   @param value    pointer to return the value
+   @param null_value if not NULL, the function will set it to true if
+   the value of variable is null, set to false if not
+
+   @retval 0 Success
+   @retval 1 Variable not found
+*/
+int get_user_var_int(const char *name,
+                     long long int *value, int *null_value);
+
+/**
+   Get the value of user variable as a double precision float number.
+
+   This function will return the value of variable @a name as real
+   number. If the original value of the variable is not a real number,
+   the value will be converted into a real number.
+
+   @param name     user variable name
+   @param value    pointer to return the value
+   @param null_value if not NULL, the function will set it to true if
+   the value of variable is null, set to false if not
+
+   @retval 0 Success
+   @retval 1 Variable not found
+*/
+int get_user_var_real(const char *name,
+                      double *value, int *null_value);
+
+/**
+   Get the value of user variable as a string.
+
+   This function will return the value of variable @a name as
+   string. If the original value of the variable is not a string,
+   the value will be converted into a string.
+
+   @param name     user variable name
+   @param value    pointer to the value buffer
+   @param len      length of the value buffer
+   @param precision precision of the value if it is a float number
+   @param null_value if not NULL, the function will set it to true if
+   the value of variable is null, set to false if not
+
+   @retval 0 Success
+   @retval 1 Variable not found
+*/
+int get_user_var_str(const char *name,
+                     char *value, unsigned long len,
+                     unsigned int precision, int *null_value);
+
+  
 #ifdef __cplusplus
 }
 #endif

include/mysql/plugin.h.pp

+#include <stdlib.h>
+typedef struct st_mysql MYSQL;
 struct st_mysql_lex_string
 {
   char *str;
@@ -105,6 +107,9 @@ struct st_mysql_information_schema
 {
   int interface_version;
 };
+struct Mysql_replication {
+  int interface_version;
+};
 struct st_mysql_value
 {
   int (*value_type)(struct st_mysql_value *);
@@ -137,3 +142,10 @@ void thd_get_xid(const void* thd, MYSQL_XID *xid);
 void mysql_query_cache_invalidate4(void* thd,
                                    const char *key, unsigned int key_length,
                                    int using_trx);
+int get_user_var_int(const char *name,
+                     long long int *value, int *null_value);
+int get_user_var_real(const char *name,
+                      double *value, int *null_value);
+int get_user_var_str(const char *name,
+                     char *value, unsigned long len,
+                     unsigned int precision, int *null_value);

libmysqld/CMakeLists.txt

@@ -139,6 +139,7 @@ SET(LIBMYSQLD_SOURCES emb_qcache.cc libmysqld.c lib_sql.cc
            ../sql/time.cc ../sql/tztime.cc ../sql/uniques.cc ../sql/unireg.cc
            ../sql/partition_info.cc ../sql/sql_connect.cc 
            ../sql/scheduler.cc ../sql/event_parse_data.cc
+           ../sql/rpl_handler.cc
            ${GEN_SOURCES}
            ${LIB_SOURCES})
 

libmysqld/Makefile.am

@@ -76,7 +76,8 @@ sqlsources = derror.cc field.cc field_conv.cc strfunc.cc filesort.cc \
 	rpl_filter.cc sql_partition.cc sql_builtin.cc sql_plugin.cc \
 	sql_tablespace.cc \
 	rpl_injector.cc my_user.c partition_info.cc \
-	sql_servers.cc event_parse_data.cc
+	sql_servers.cc event_parse_data.cc \
+	rpl_handler.cc
 
 libmysqld_int_a_SOURCES= $(libmysqld_sources)
 nodist_libmysqld_int_a_SOURCES= $(libmysqlsources) $(sqlsources)

mysql-test/mysql-test-run.pl

@@ -1815,6 +1815,26 @@ sub environment_setup {
     $ENV{'EXAMPLE_PLUGIN_LOAD'}="--plugin_load=;EXAMPLE=".$plugin_filename.";";
   }
 
+  # --------------------------------------------------------------------------
+  # Add the path where mysqld will find semisync plugins
+  # --------------------------------------------------------------------------
+  my $lib_semisync_master_plugin=
+      mtr_file_exists("$basedir/plugin/semisync/.libs/libsemisync_master.so");
+  my $lib_semisync_slave_plugin=
+      mtr_file_exists("$basedir/plugin/semisync/.libs/libsemisync_slave.so");
+  if ($lib_semisync_master_plugin && $lib_semisync_slave_plugin)
+  {
+    $ENV{'SEMISYNC_MASTER_PLUGIN'}= basename($lib_semisync_master_plugin);
+    $ENV{'SEMISYNC_SLAVE_PLUGIN'}= basename($lib_semisync_slave_plugin);
+    $ENV{'SEMISYNC_PLUGIN_OPT'}= "--plugin-dir=".dirname($lib_semisync_master_plugin);
+  }
+  else
+  {
+    $ENV{'SEMISYNC_MASTER_PLUGIN'}= "";
+    $ENV{'SEMISYNC_SLAVE_PLUGIN'}= "";
+    $ENV{'SEMISYNC_PLUGIN_OPT'}="";
+  }
+
   # ----------------------------------------------------
   # Add the path where mysqld will find mypluglib.so
   # ----------------------------------------------------

mysql-test/suite/rpl/t/rpl000017.test

@@ -6,6 +6,7 @@ grant replication slave on *.* to replicate@localhost identified by 'aaaaaaaaaaa
 grant replication slave on *.* to replicate@127.0.0.1 identified by 'aaaaaaaaaaaaaaab';
 connection slave;
 start slave;
+source include/wait_for_slave_to_start.inc;
 connection master;
 --disable_warnings
 drop table if exists t1;

plugin/semisync/Makefile.am

+# Copyright (C) 2006 MySQL AB
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+## Makefile.am for semi-synchronous replication
+
+pkgplugindir =		$(pkglibdir)/plugin
+INCLUDES =              -I$(top_srcdir)/include \
+			-I$(top_srcdir)/sql \
+			-I$(srcdir)
+
+noinst_HEADERS = semisync.h semisync_master.h semisync_slave.h
+
+pkgplugin_LTLIBRARIES =	libsemisync_master.la libsemisync_slave.la
+
+libsemisync_master_la_LDFLAGS =	-module
+libsemisync_master_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+libsemisync_master_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+libsemisync_master_la_SOURCES = semisync.cc semisync_master.cc semisync_master_plugin.cc
+
+libsemisync_slave_la_LDFLAGS =	-module
+libsemisync_slave_la_CXXFLAGS=	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+libsemisync_slave_la_CFLAGS =	$(AM_CFLAGS) -DMYSQL_DYNAMIC_PLUGIN
+libsemisync_slave_la_SOURCES = semisync.cc semisync_slave.cc semisync_slave_plugin.cc

plugin/semisync/configure.in

+# configure.in for semi-synchronous replication
+
+AC_INIT(mysql-semi-sync-plugin, 0.2)
+AM_INIT_AUTOMAKE
+AC_DISABLE_STATIC
+AC_PROG_LIBTOOL
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
+

plugin/semisync/plug.in

+MYSQL_PLUGIN(semisync,[Semi-synchronous Replication Plugin],
+        [Semi-synchronous replication plugin.])
+MYSQL_PLUGIN_DYNAMIC(semisync,   [libsemisync_master.la libsemisync_slave.la])

plugin/semisync/semisync.cc

+/* Copyright (C) 2007 Google Inc.
+   Copyright (C) 2008 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+
+#include "semisync.h"
+
+const unsigned char ReplSemiSyncBase::kPacketMagicNum = 0xef;
+const unsigned char ReplSemiSyncBase::kPacketFlagSync = 0x01;
+
+
+const unsigned long Trace::kTraceGeneral  = 0x0001;
+const unsigned long Trace::kTraceDetail   = 0x0010;
+const unsigned long Trace::kTraceNetWait  = 0x0020;
+const unsigned long Trace::kTraceFunction = 0x0040;
+
+const char  ReplSemiSyncBase::kSyncHeader[2] =
+  {ReplSemiSyncBase::kPacketMagicNum, 0};

plugin/semisync/semisync.h

+/* Copyright (C) 2007 Google Inc.
+   Copyright (C) 2008 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+
+#ifndef SEMISYNC_H
+#define SEMISYNC_H
+
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+#include <sys/time.h>
+#include <time.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <mysql.h>
+
+typedef uint32_t uint32;
+typedef unsigned long long my_off_t;
+#define FN_REFLEN	512	/* Max length of full path-name */
+void sql_print_error(const char *format, ...);
+void sql_print_warning(const char *format, ...);
+void sql_print_information(const char *format, ...);
+extern unsigned long max_connections;
+
+#define MYSQL_SERVER
+#define HAVE_REPLICATION
+#include <my_global.h>
+#include <my_pthread.h>
+#include <mysql/plugin.h>
+#include <replication.h>
+
+typedef struct st_mysql_show_var SHOW_VAR;
+typedef struct st_mysql_sys_var SYS_VAR;
+
+
+/**
+   This class is used to trace function calls and other process
+   information
+*/
+class Trace {
+public:
+  static const unsigned long kTraceFunction;
+  static const unsigned long kTraceGeneral;
+  static const unsigned long kTraceDetail;
+  static const unsigned long kTraceNetWait;
+
+  unsigned long           trace_level_;                      /* the level for tracing */
+
+  inline void function_enter(const char *func_name)
+  {
+    if (trace_level_ & kTraceFunction)
+      sql_print_information("---> %s enter", func_name);
+  }
+  inline int  function_exit(const char *func_name, int exit_code)
+  {
+    if (trace_level_ & kTraceFunction)
+      sql_print_information("<--- %s exit (%d)", func_name, exit_code);
+    return exit_code;
+  }
+
+  Trace()
+    :trace_level_(0L)
+  {}
+  Trace(unsigned long trace_level)
+    :trace_level_(trace_level)
+  {}
+};
+
+/**
+   Base class for semi-sync master and slave classes
+*/
+class ReplSemiSyncBase
+  :public Trace {
+public:
+  static const char  kSyncHeader[2];              /* three byte packet header */
+
+  /* Constants in network packet header. */
+  static const unsigned char kPacketMagicNum;
+  static const unsigned char kPacketFlagSync;
+};
+
+#endif /* SEMISYNC_H */

plugin/semisync/semisync_slave.cc

+/* Copyright (C) 2008 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+
+#include "semisync_slave.h"
+
+char rpl_semi_sync_slave_enabled;
+unsigned long rpl_semi_sync_slave_status= 0;
+unsigned long rpl_semi_sync_slave_trace_level;
+
+int ReplSemiSyncSlave::initObject()
+{
+  int result= 0;
+  const char *kWho = "ReplSemiSyncSlave::initObject";
+
+  if (init_done_)
+  {
+    fprintf(stderr, "%s called twice\n", kWho);
+    return 1;
+  }
+  init_done_ = true;
+
+  /* References to the parameter works after set_options(). */
+  setSlaveEnabled(rpl_semi_sync_slave_enabled);
+  setTraceLevel(rpl_semi_sync_slave_trace_level);
+
+  return result;
+}
+
+int ReplSemiSyncSlave::slaveReplyConnect()
+{
+  if (!mysql_reply && !(mysql_reply= rpl_connect_master(NULL)))
+  {
+    sql_print_error("Semisync slave connect to master for reply failed");
+    return 1;
+  }
+  return 0;
+}
+
+int ReplSemiSyncSlave::slaveReadSyncHeader(const char *header,
+                                      unsigned long total_len,
+                                      bool  *need_reply,
+                                      const char **payload,
+                                      unsigned long *payload_len)
+{
+  const char *kWho = "ReplSemiSyncSlave::slaveReadSyncHeader";
+  int read_res = 0;
+  function_enter(kWho);
+
+  if ((unsigned char)(header[0]) == kPacketMagicNum)
+  {
+    *need_reply  = (header[1] & kPacketFlagSync);
+    *payload_len = total_len - 2;
+    *payload     = header + 2;
+
+    if (trace_level_ & kTraceDetail)
+      sql_print_information("%s: reply - %d", kWho, *need_reply);
+  }
+  else
+  {
+    sql_print_error("Missing magic number for semi-sync packet, packet "
+                    "len: %lu", total_len);
+    read_res = -1;
+  }
+
+  return function_exit(kWho, read_res);
+}
+
+int ReplSemiSyncSlave::slaveStart(Binlog_relay_IO_param *param)
+{
+  bool semi_sync= getSlaveEnabled();
+  
+  sql_print_information("Slave I/O thread: Start %s replication to\
+ master '%s@%s:%d' in log '%s' at position %lu",
+			semi_sync ? "semi-sync" : "asynchronous",
+			param->user, param->host, param->port,
+			param->master_log_name[0] ? param->master_log_name : "FIRST",
+			(unsigned long)param->master_log_pos);
+
+  if (semi_sync && !rpl_semi_sync_slave_status)
+    rpl_semi_sync_slave_status= 1;
+  return 0;
+}
+
+int ReplSemiSyncSlave::slaveStop(Binlog_relay_IO_param *param)
+{
+  if (rpl_semi_sync_slave_status)
+    rpl_semi_sync_slave_status= 0;
+  if (mysql_reply)
+    mysql_close(mysql_reply);
+  mysql_reply= 0;
+  return 0;
+}
+
+int ReplSemiSyncSlave::slaveReply(const char *log_name, my_off_t log_pos)
+{
+  char query[FN_REFLEN + 100];
+  sprintf(query, "SET SESSION rpl_semi_sync_master_reply_log_file_pos='%llu:%s'",
+          (unsigned long long)log_pos, log_name);
+  if (mysql_real_query(mysql_reply, query, strlen(query)))
+  {
+    sql_print_error("Set 'rpl_semi_sync_master_reply_log_file_pos' on master failed");
+    mysql_free_result(mysql_store_result(mysql_reply));
+    mysql_close(mysql_reply);
+    mysql_reply= 0;
+    return 1;
+  }
+  mysql_free_result(mysql_store_result(mysql_reply));
+  return 0;
+}

plugin/semisync/semisync_slave.h

+/* Copyright (C) 2006 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+
+#ifndef SEMISYNC_SLAVE_H
+#define SEMISYNC_SLAVE_H
+
+#include "semisync.h"
+
+/**
+   The extension class for the slave of semi-synchronous replication
+*/
+class ReplSemiSyncSlave
+  :public ReplSemiSyncBase {
+public:
+ ReplSemiSyncSlave()
+   :slave_enabled_(false)
+  {}
+  ~ReplSemiSyncSlave() {}
+
+  void setTraceLevel(unsigned long trace_level) {
+    trace_level_ = trace_level;
+  }
+
+  /* Initialize this class after MySQL parameters are initialized. this
+   * function should be called once at bootstrap time.
+   */
+  int initObject();
+
+  bool getSlaveEnabled() {
+    return slave_enabled_;
+  }
+  void setSlaveEnabled(bool enabled) {
+    slave_enabled_ = enabled;
+  }
+
+  /* A slave reads the semi-sync packet header and separate the metadata
+   * from the payload data.
+   * 
+   * Input:
+   *  header      - (IN)  packet header pointer
+   *  total_len   - (IN)  total packet length: metadata + payload
+   *  need_reply  - (IN)  whether the master is waiting for the reply
+   *  payload     - (IN)  payload: the replication event
+   *  payload_len - (IN)  payload length
+   *
+   * Return:
+   *  0: success;  -1 or otherwise: error
+   */
+  int slaveReadSyncHeader(const char *header, unsigned long total_len, bool *need_reply,
+                          const char **payload, unsigned long *payload_len);
+
+  /* A slave replies to the master indicating its replication process.  It
+   * indicates that the slave has received all events before the specified
+   * binlog position.
+   * 
+   * Input:
+   *  log_name         - (IN)  the reply point's binlog file name
+   *  log_pos   - (IN)  the reply point's binlog file offset
+   *
+   * Return:
+   *  0: success;  -1 or otherwise: error
+   */
+  int slaveReply(const char *log_name, my_off_t log_pos);
+
+  /*
+    Connect to master for sending reply
+   */
+  int slaveReplyConnect();
+  
+  int slaveStart(Binlog_relay_IO_param *param);
+  int slaveStop(Binlog_relay_IO_param *param);
+
+private:
+  /* True when initObject has been called */
+  bool init_done_;
+  bool slave_enabled_;        /* semi-sycn is enabled on the slave */
+  MYSQL *mysql_reply;         /* connection to send reply */
+};
+
+
+/* System and status variables for the slave component */
+extern char rpl_semi_sync_slave_enabled;
+extern unsigned long rpl_semi_sync_slave_trace_level;
+extern unsigned long rpl_semi_sync_slave_status;
+
+#endif /* SEMISYNC_SLAVE_H */

plugin/semisync/semisync_slave_plugin.cc

+/* Copyright (C) 2007 Google Inc.
+   Copyright (C) 2008 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+
+#include "semisync_slave.h"
+
+ReplSemiSyncSlave repl_semisync;
+
+/*
+  indicate whether or not the slave should send a reply to the master.
+
+  This is set to true in repl_semi_slave_read_event if the current
+  event read is the last event of a transaction. And the value is
+  checked in repl_semi_slave_queue_event.
+*/
+bool semi_sync_need_reply= false;
+
+int repl_semi_reset_slave(Binlog_relay_IO_param *param)
+{
+  // TODO: reset semi-sync slave status here
+  return 0;
+}
+
+int repl_semi_slave_request_dump(Binlog_relay_IO_param *param,
+				 uint32 flags)
+{
+  MYSQL *mysql= param->mysql;
+  MYSQL_RES *res= 0;
+  MYSQL_ROW row;
+  const char *query;
+
+  if (!repl_semisync.getSlaveEnabled())
+    return 0;
+
+  /*
+    Create the connection that is used to send slave ACK replies to
+    master
+  */
+  if (repl_semisync.slaveReplyConnect())
+    return 1;
+
+  /* Check if master server has semi-sync plugin installed */
+  query= "SHOW VARIABLES LIKE 'rpl_semi_sync_master_enabled'";
+  if (mysql_real_query(mysql, query, strlen(query)) ||
+      !(res= mysql_store_result(mysql)))
+  {
+    mysql_free_result(mysql_store_result(mysql));
+    sql_print_error("Execution failed on master: %s", query);
+    return 1;
+  }
+
+  row= mysql_fetch_row(res);
+  if (!row || strcmp(row[1], "ON"))
+  {
+    /* Master does not support or not configured semi-sync */
+    sql_print_warning("Master server does not support or not configured semi-sync replication, fallback to asynchronous");
+    rpl_semi_sync_slave_status= 0;
+    return 0;
+  }
+
+  /*
+    Tell master dump thread that we want to do semi-sync
+    replication
+  */
+  query= "SET @rpl_semi_sync_slave= 1";
+  if (mysql_real_query(mysql, query, strlen(query)))
+  {
+    sql_print_error("Set 'rpl_semi_sync_slave=1' on master failed");
+    mysql_free_result(mysql_store_result(mysql));
+    return 1;
+  }
+  mysql_free_result(mysql_store_result(mysql));
+  rpl_semi_sync_slave_status= 1;
+  return 0;
+}
+
+int repl_semi_slave_read_event(Binlog_relay_IO_param *param,
+			       const char *packet, unsigned long len,
+			       const char **event_buf, unsigned long *event_len)
+{
+  if (rpl_semi_sync_slave_status)
+    return repl_semisync.slaveReadSyncHeader(packet, len,
+					     &semi_sync_need_reply,
+					     event_buf, event_len);
+  *event_buf= packet;
+  *event_len= len;
+  return 0;
+}
+
+int repl_semi_slave_queue_event(Binlog_relay_IO_param *param,
+				const char *event_buf,
+				unsigned long event_len,
+				uint32 flags)
+{
+  if (rpl_semi_sync_slave_status && semi_sync_need_reply)
+    return repl_semisync.slaveReply(param->master_log_name,
+                                    param->master_log_pos);
+  return 0;
+}
+
+int repl_semi_slave_io_start(Binlog_relay_IO_param *param)
+{
+  return repl_semisync.slaveStart(param);
+}
+
+int repl_semi_slave_io_end(Binlog_relay_IO_param *param)
+{
+  return repl_semisync.slaveStop(param);
+}
+
+
+static void fix_rpl_semi_sync_slave_enabled(MYSQL_THD thd,
+					    SYS_VAR *var,
+					    void *ptr,
+					    const void *val)
+{
+  *(char *)ptr= *(char *)val;
+  repl_semisync.setSlaveEnabled(rpl_semi_sync_slave_enabled != 0);
+  return;
+}
+
+static void fix_rpl_semi_sync_trace_level(MYSQL_THD thd,
+					  SYS_VAR *var,
+					  void *ptr,
+					  const void *val)
+{
+  *(unsigned long *)ptr= *(unsigned long *)val;
+  repl_semisync.setTraceLevel(rpl_semi_sync_slave_trace_level);
+  return;
+}
+
+/* plugin system variables */
+static MYSQL_SYSVAR_BOOL(enabled, rpl_semi_sync_slave_enabled,
+  PLUGIN_VAR_OPCMDARG,
+ "Enable semi-synchronous replication slave (disabled by default). ",
+  NULL,				   // check
+  &fix_rpl_semi_sync_slave_enabled, // update
+  0);
+
+static MYSQL_SYSVAR_ULONG(trace_level, rpl_semi_sync_slave_trace_level,
+  PLUGIN_VAR_OPCMDARG,
+ "The tracing level for semi-sync replication.",
+  NULL,				  // check
+  &fix_rpl_semi_sync_trace_level, // update
+  32, 0, ~0L, 1);
+
+static SYS_VAR* semi_sync_slave_system_vars[]= {
+  MYSQL_SYSVAR(enabled),
+  MYSQL_SYSVAR(trace_level),
+  NULL,
+};
+
+
+/* plugin status variables */
+static SHOW_VAR semi_sync_slave_status_vars[]= {
+  {"Rpl_semi_sync_slave_status",
+   (char*) &rpl_semi_sync_slave_status,    SHOW_BOOL},
+  {NULL, NULL, SHOW_BOOL},
+};
+
+Binlog_relay_IO_observer relay_io_observer = {
+  sizeof(Binlog_relay_IO_observer), // len
+
+  repl_semi_slave_io_start,	// start
+  repl_semi_slave_io_end,	// stop
+  repl_semi_slave_request_dump,	// request_transmit
+  repl_semi_slave_read_event,	// after_read_event
+  repl_semi_slave_queue_event,	// after_queue_event
+  repl_semi_reset_slave,	// reset
+};
+
+static int semi_sync_slave_plugin_init(void *p)
+{
+  if (repl_semisync.initObject())
+    return 1;
+  if (register_binlog_relay_io_observer(&relay_io_observer, p))
+    return 1;
+  return 0;
+}
+
+static int semi_sync_slave_plugin_deinit(void *p)
+{
+  if (unregister_binlog_relay_io_observer(&relay_io_observer, p))
+    return 1;
+  return 0;
+}
+
+
+struct Mysql_replication semi_sync_slave_plugin= {
+  MYSQL_REPLICATION_INTERFACE_VERSION
+};
+
+/*
+  Plugin library descriptor
+*/
+mysql_declare_plugin(semi_sync_slave)
+{
+  MYSQL_REPLICATION_PLUGIN,
+  &semi_sync_slave_plugin,
+  "rpl_semi_sync_slave",
+  "He Zhenxing",
+  "Semi-synchronous replication slave",
+  PLUGIN_LICENSE_GPL,
+  semi_sync_slave_plugin_init, /* Plugin Init */
+  semi_sync_slave_plugin_deinit, /* Plugin Deinit */
+  0x0100 /* 1.0 */,
+  semi_sync_slave_status_vars,	/* status variables */
+  semi_sync_slave_system_vars,	/* system variables */
+  NULL                        /* config options                  */
+}
+mysql_declare_plugin_end;

sql/CMakeLists.txt

@@ -75,6 +75,7 @@ SET (SQL_SOURCE
                rpl_rli.cc rpl_mi.cc sql_servers.cc
                sql_connect.cc scheduler.cc 
                sql_profile.cc event_parse_data.cc
+               rpl_handler.cc
                ${PROJECT_SOURCE_DIR}/sql/sql_yacc.cc
                ${PROJECT_SOURCE_DIR}/sql/sql_yacc.h
                ${PROJECT_SOURCE_DIR}/include/mysqld_error.h

sql/Makefile.am

@@ -76,7 +76,8 @@ noinst_HEADERS =	item.h item_func.h item_sum.h item_cmpfunc.h \
 			sql_plugin.h authors.h event_parse_data.h \
 			event_data_objects.h event_scheduler.h \
 			sql_partition.h partition_info.h partition_element.h \
-			contributors.h sql_servers.h
+			contributors.h sql_servers.h \
+			rpl_handler.h replication.h
 
 mysqld_SOURCES =	sql_lex.cc sql_handler.cc sql_partition.cc \
 			item.cc item_sum.cc item_buff.cc item_func.cc \
@@ -120,7 +121,8 @@ mysqld_SOURCES =	sql_lex.cc sql_handler.cc sql_partition.cc \
                         event_queue.cc event_db_repository.cc events.cc \
 			sql_plugin.cc sql_binlog.cc \
 			sql_builtin.cc sql_tablespace.cc partition_info.cc \
-			sql_servers.cc event_parse_data.cc
+			sql_servers.cc event_parse_data.cc \
+			rpl_handler.cc
 
 nodist_mysqld_SOURCES =	mini_client_errors.c pack.c client.c my_time.c my_user.c 
 

sql/handler.cc

@@ -24,6 +24,7 @@
 #endif
 
 #include "mysql_priv.h"
+#include "rpl_handler.h"
 #include "rpl_filter.h"
 #include <myisampack.h>
 #include <errno.h>
@@ -221,6 +222,8 @@ handlerton *ha_checktype(THD *thd, enum legacy_db_type database_type,
     return NULL;
   }
 
+  RUN_HOOK(transaction, after_rollback, (thd, FALSE));
+
   switch (database_type) {
 #ifndef NO_HASH
   case DB_TYPE_HASH:
@@ -1190,6 +1193,7 @@ int ha_commit_trans(THD *thd, bool all)
     if (cookie)
       tc_log->unlog(cookie, xid);
     DBUG_EXECUTE_IF("crash_commit_after", abort(););
+    RUN_HOOK(transaction, after_commit, (thd, FALSE));
 end:
     if (rw_trans)
       start_waiting_global_read_lock(thd);
@@ -1337,6 +1341,7 @@ int ha_rollback_trans(THD *thd, bool all)
     push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                  ER_WARNING_NOT_COMPLETE_ROLLBACK,
                  ER(ER_WARNING_NOT_COMPLETE_ROLLBACK));
+  RUN_HOOK(transaction, after_rollback, (thd, FALSE));
   DBUG_RETURN(error);
 }
 
@@ -1371,7 +1376,14 @@ int ha_autocommit_or_rollback(THD *thd, int error)
 
     thd->variables.tx_isolation=thd->session_tx_isolation;
   }
+  else
 #endif
+  {
+    if (!error)
+      RUN_HOOK(transaction, after_commit, (thd, FALSE));
+    else
+      RUN_HOOK(transaction, after_rollback, (thd, FALSE));
+  }
   DBUG_RETURN(error);
 }
 

sql/log.cc

@@ -38,6 +38,7 @@
 #endif
 
 #include <mysql/plugin.h>
+#include "rpl_handler.h"
 
 /* max size of the log message */
 #define MAX_LOG_BUFFER_SIZE 1024
@@ -3683,9 +3684,11 @@ err:
 }
 
 
-bool MYSQL_BIN_LOG::flush_and_sync()
+bool MYSQL_BIN_LOG::flush_and_sync(bool *synced)
 {
   int err=0, fd=log_file.file;
+  if (synced)
+    *synced= 0;
   safe_mutex_assert_owner(&LOCK_log);
   if (flush_io_cache(&log_file))
     return 1;
@@ -3693,6 +3696,8 @@ bool MYSQL_BIN_LOG::flush_and_sync()
   {
     sync_binlog_counter= 0;
     err=my_sync(fd, MYF(MY_WME));
+    if (synced)
+      *synced= 1;
   }
   return err;
 }
@@ -3983,7 +3988,7 @@ MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
 
     if (file == &log_file)
     {
-      error= flush_and_sync();
+      error= flush_and_sync(0);
       if (!error)
       {
         signal_update();
@@ -4169,8 +4174,16 @@ bool MYSQL_BIN_LOG::write(Log_event *event_info)
 
     if (file == &log_file) // we are writing to the real log (disk)
     {
-      if (flush_and_sync())
+      bool synced= 0;
+      if (flush_and_sync(&synced))
 	goto err;
+
+      if (RUN_HOOK(binlog_storage, after_flush,
+                   (thd, log_file_name, file->pos_in_file, synced))) {
+        sql_print_error("Failed to run 'after_flush' hooks");
+        goto err;
+      }
+
       signal_update();
       rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED);
     }
@@ -4425,7 +4438,7 @@ int MYSQL_BIN_LOG::write_cache(IO_CACHE *cache, bool lock_log, bool sync_log)
   DBUG_ASSERT(carry == 0);
 
   if (sync_log)
-    flush_and_sync();
+    flush_and_sync(0);
 
   return 0;                                     // All OK
 }
@@ -4472,7 +4485,7 @@ bool MYSQL_BIN_LOG::write_incident(THD *thd, bool lock)
   ev.write(&log_file);
   if (lock)
   {
-    if (!error && !(error= flush_and_sync()))
+    if (!error && !(error= flush_and_sync(0)))
     {
       signal_update();
       rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED);
@@ -4560,7 +4573,8 @@ bool MYSQL_BIN_LOG::write(THD *thd, IO_CACHE *cache, Log_event *commit_event,
       if (incident && write_incident(thd, FALSE))
         goto err;
 
-      if (flush_and_sync())
+      bool synced= 0;
+      if (flush_and_sync(&synced))
         goto err;
       DBUG_EXECUTE_IF("half_binlogged_transaction", abort(););
       if (cache->error)				// Error on read
@@ -4569,6 +4583,15 @@ bool MYSQL_BIN_LOG::write(THD *thd, IO_CACHE *cache, Log_event *commit_event,
         write_error=1;				// Don't give more errors
         goto err;
       }
+
+      if (RUN_HOOK(binlog_storage, after_flush,
+                   (thd, log_file_name, log_file.pos_in_file, synced)))
+      {
+        sql_print_error("Failed to run 'after_flush' hooks");
+        write_error=1;
+        goto err;
+      }
+
       signal_update();
     }
 

sql/log.h

@@ -378,7 +378,21 @@ public:
   bool is_active(const char* log_file_name);
   int update_log_index(LOG_INFO* linfo, bool need_update_threads);
   void rotate_and_purge(uint flags);
-  bool flush_and_sync();
+
+  /**
+     Flush binlog cache and synchronize to disk.
+
+     This function flushes events in binlog cache to binary log file,
+     it will do synchronizing according to the setting of system
+     variable 'sync_binlog'. If file is synchronized, @c synced will
+     be set to 1, otherwise 0.
+
+     @param[out] synced if not NULL, set to 1 if file is synchronized, otherwise 0
+
+     @retval 0 Success
+     @retval other Failure
+  */
+  bool flush_and_sync(bool *synced);
   int purge_logs(const char *to_log, bool included,
                  bool need_mutex, bool need_update_threads,
                  ulonglong *decrease_log_space);

sql/mysqld.cc

@@ -31,6 +31,8 @@
 
 #include "rpl_injector.h"
 
+#include "rpl_handler.h"
+
 #ifdef HAVE_SYS_PRCTL_H
 #include <sys/prctl.h>
 #endif
@@ -1284,6 +1286,7 @@ void clean_up(bool print_message)
   ha_end();
   if (tc_log)
     tc_log->close();
+  delegates_destroy();
   xid_cache_free();
   delete_elements(&key_caches, (void (*)(const char*, uchar*)) free_key_cache);
   multi_keycache_free();
@@ -3760,6 +3763,13 @@ static int init_server_components()
     unireg_abort(1);
   }
 
+  /* initialize delegates for extension observers */
+  if (delegates_init())
+  {
+    sql_print_error("Initialize extension delegates failed");
+    unireg_abort(1);
+  }
+
   /* need to configure logging before initializing storage engines */
   if (opt_update_log)
   {

sql/rpl_handler.h

+/* Copyright (C) 2008 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifndef RPL_HANDLER_H
+#define RPL_HANDLER_H
+
+#include "mysql_priv.h"
+#include "rpl_mi.h"
+#include "rpl_rli.h"
+#include "sql_plugin.h"
+#include "replication.h"
+
+class Observer_info {
+public:
+  void *observer;
+  st_plugin_int *plugin_int;
+  plugin_ref plugin;
+
+  Observer_info(void *ob, st_plugin_int *p)
+    :observer(ob), plugin_int(p)
+  {
+    plugin= plugin_int_to_ref(plugin_int);
+  }
+};
+
+class Delegate {
+public:
+  typedef List<Observer_info> Observer_info_list;
+  typedef List_iterator<Observer_info> Observer_info_iterator;
+  
+  int add_observer(void *observer, st_plugin_int *plugin)
+  {
+    int ret= FALSE;
+    if (!inited)
+      return TRUE;
+    write_lock();
+    Observer_info_iterator iter(observer_info_list);
+    Observer_info *info= iter++;
+    while (info && info->observer != observer)
+      info= iter++;
+    if (!info)
+    {
+      info= new Observer_info(observer, plugin);
+      if (!info || observer_info_list.push_back(info, &memroot))
+        ret= TRUE;
+    }
+    else
+      ret= TRUE;
+    unlock();
+    return ret;
+  }
+  
+  int remove_observer(void *observer, st_plugin_int *plugin)
+  {
+    int ret= FALSE;
+    if (!inited)
+      return TRUE;
+    write_lock();
+    Observer_info_iterator iter(observer_info_list);
+    Observer_info *info= iter++;
+    while (info && info->observer != observer)
+      info= iter++;
+    if (info)
+      iter.remove();
+    else
+      ret= TRUE;
+    unlock();
+    return ret;
+  }
+
+  inline Observer_info_iterator observer_info_iter()
+  {
+    return Observer_info_iterator(observer_info_list);
+  }
+
+  inline bool is_empty()
+  {
+    return observer_info_list.is_empty();
+  }
+
+  inline int read_lock()
+  {
+    if (!inited)
+      return TRUE;
+    return rw_rdlock(&lock);
+  }
+
+  inline int write_lock()
+  {
+    if (!inited)
+      return TRUE;
+    return rw_wrlock(&lock);
+  }
+
+  inline int unlock()
+  {
+    if (!inited)
+      return TRUE;
+    return rw_unlock(&lock);
+  }
+
+  inline bool is_inited()
+  {
+    return inited;
+  }
+  
+  Delegate()
+  {
+    inited= FALSE;
+    if (my_rwlock_init(&lock, NULL))
+      return;
+    init_sql_alloc(&memroot, 1024, 0);
+    inited= TRUE;
+  }
+  ~Delegate()
+  {
+    inited= FALSE;
+    rwlock_destroy(&lock);
+    free_root(&memroot, MYF(0));
+  }
+
+private:
+  Observer_info_list observer_info_list;
+  rw_lock_t lock;
+  MEM_ROOT memroot;
+  bool inited;
+};
+
+class Trans_delegate
+  :public Delegate {
+public:
+  typedef Trans_observer Observer;
+  int before_commit(THD *thd, bool all);
+  int before_rollback(THD *thd, bool all);
+  int after_commit(THD *thd, bool all);
+  int after_rollback(THD *thd, bool all);
+};
+
+class Binlog_storage_delegate
+  :public Delegate {
+public:
+  typedef Binlog_storage_observer Observer;
+  int after_flush(THD *thd, const char *log_file,
+                  my_off_t log_pos, bool synced);
+};
+
+#ifdef HAVE_REPLICATION
+class Binlog_transmit_delegate
+  :public Delegate {
+public:
+  typedef Binlog_transmit_observer Observer;
+  int transmit_start(THD *thd, ushort flags,
+                     const char *log_file, my_off_t log_pos);
+  int transmit_stop(THD *thd, ushort flags);
+  int reserve_header(THD *thd, ushort flags, String *packet);
+  int before_send_event(THD *thd, ushort flags,
+                        String *packet, const
+                        char *log_file, my_off_t log_pos );
+  int after_send_event(THD *thd, ushort flags,
+                       String *packet);
+  int after_reset_master(THD *thd, ushort flags);
+};
+
+class Binlog_relay_IO_delegate
+  :public Delegate {
+public:
+  typedef Binlog_relay_IO_observer Observer;
+  int thread_start(THD *thd, Master_info *mi);
+  int thread_stop(THD *thd, Master_info *mi);
+  int before_request_transmit(THD *thd, Master_info *mi, ushort flags);
+  int after_read_event(THD *thd, Master_info *mi,
+                       const char *packet, ulong len,
+                       const char **event_buf, ulong *event_len);
+  int after_queue_event(THD *thd, Master_info *mi,
+                        const char *event_buf, ulong event_len,
+                        bool synced);
+  int after_reset_slave(THD *thd, Master_info *mi);
+private:
+  void init_param(Binlog_relay_IO_param *param, Master_info *mi);
+};
+#endif /* HAVE_REPLICATION */
+
+int delegates_init();
+void delegates_destroy();
+
+extern Trans_delegate *transaction_delegate;
+extern Binlog_storage_delegate *binlog_storage_delegate;
+#ifdef HAVE_REPLICATION
+extern Binlog_transmit_delegate *binlog_transmit_delegate;
+extern Binlog_relay_IO_delegate *binlog_relay_io_delegate;
+#endif /* HAVE_REPLICATION */
+
+/*
+  if there is no observers in the delegate, we can return 0
+  immediately.
+*/
+#define RUN_HOOK(group, hook, args)             \
+  (group ##_delegate->is_empty() ?              \
+   0 : group ##_delegate->hook args)
+
+#endif /* RPL_HANDLER_H */

sql/slave.cc

@@ -40,6 +40,7 @@
 #include <errmsg.h>
 #include <mysqld_error.h>
 #include <mysys_err.h>
+#include "rpl_handler.h"
 
 #ifdef HAVE_REPLICATION
 
@@ -69,6 +70,8 @@ ulonglong relay_log_space_limit = 0;
 int disconnect_slave_event_count = 0, abort_slave_event_count = 0;
 int events_till_abort = -1;
 
+static pthread_key(Master_info*, RPL_MASTER_INFO);
+
 enum enum_slave_reconnect_actions
 {
   SLAVE_RECON_ACT_REG= 0,
@@ -231,6 +234,10 @@ int init_slave()
     TODO: re-write this to interate through the list of files
     for multi-master
   */
+
+  if (pthread_key_create(&RPL_MASTER_INFO, NULL))
+    goto err;
+
   active_mi= new Master_info;
 
   /*
@@ -1868,17 +1875,22 @@ static int safe_sleep(THD* thd, int sec, CHECK_KILLED_FUNC thread_killed,
 }
 
 
-static int request_dump(MYSQL* mysql, Master_info* mi,
-                        bool *suppress_warnings)
+static int request_dump(THD *thd, MYSQL* mysql, Master_info* mi,
+			bool *suppress_warnings)
 {
   uchar buf[FN_REFLEN + 10];
   int len;
-  int binlog_flags = 0; // for now
+  ushort binlog_flags = 0; // for now
   char* logname = mi->master_log_name;
   DBUG_ENTER("request_dump");
   
   *suppress_warnings= FALSE;
 
+  if (RUN_HOOK(binlog_relay_io,
+               before_request_transmit,
+               (thd, mi, binlog_flags)))
+    DBUG_RETURN(1);
+  
   // TODO if big log files: Change next to int8store()
   int4store(buf, (ulong) mi->master_log_pos);
   int2store(buf + 4, binlog_flags);
@@ -2532,6 +2544,16 @@ pthread_handler_t handle_slave_io(void *arg)
                             mi->master_log_name,
                             llstr(mi->master_log_pos,llbuff)));
 
+  /* This must be called before run any binlog_relay_io hooks */
+  my_pthread_setspecific_ptr(RPL_MASTER_INFO, mi);
+
+  if (RUN_HOOK(binlog_relay_io, thread_start, (thd, mi)))
+  {
+    mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
+               ER(ER_SLAVE_FATAL_ERROR), "Failed to run 'thread_start' hook");
+    goto err;
+  }
+
   if (!(mi->mysql = mysql = mysql_init(NULL)))
   {
     mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
@@ -2621,7 +2643,7 @@ connected:
   while (!io_slave_killed(thd,mi))
   {
     thd_proc_info(thd, "Requesting binlog dump");
-    if (request_dump(mysql, mi, &suppress_warnings))
+    if (request_dump(thd, mysql, mi, &suppress_warnings))
     {
       sql_print_error("Failed on request_dump()");
       if (check_io_slave_killed(thd, mi, "Slave I/O thread killed while \
@@ -2641,6 +2663,7 @@ requesting master dump") ||
           goto err;
         goto connected;
       });
+    const char *event_buf;
 
     DBUG_ASSERT(mi->last_error().number == 0);
     while (!io_slave_killed(thd,mi))
@@ -2697,14 +2720,37 @@ Stopping slave I/O thread due to out-of-memory error from master");
 
       retry_count=0;                    // ok event, reset retry counter
       thd_proc_info(thd, "Queueing master event to the relay log");
-      if (queue_event(mi,(const char*)mysql->net.read_pos + 1,
-                      event_len))
+      event_buf= (const char*)mysql->net.read_pos + 1;
+      if (RUN_HOOK(binlog_relay_io, after_read_event,
+                   (thd, mi,(const char*)mysql->net.read_pos + 1,
+                    event_len, &event_buf, &event_len)))
+      {
+        mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
+                   ER(ER_SLAVE_FATAL_ERROR),
+                   "Failed to run 'after_read_event' hook");
+        goto err;
+      }
+
+      /* XXX: 'synced' should be updated by queue_event to indicate
+         whether event has been synced to disk */
+      bool synced= 0;
+      if (queue_event(mi, event_buf, event_len))
       {
         mi->report(ERROR_LEVEL, ER_SLAVE_RELAY_LOG_WRITE_FAILURE,
                    ER(ER_SLAVE_RELAY_LOG_WRITE_FAILURE),
                    "could not queue event from master");
         goto err;
       }
+
+      if (RUN_HOOK(binlog_relay_io, after_queue_event,
+                   (thd, mi, event_buf, event_len, synced)))
+      {
+        mi->report(ERROR_LEVEL, ER_SLAVE_FATAL_ERROR,
+                   ER(ER_SLAVE_FATAL_ERROR),
+                   "Failed to run 'after_queue_event' hook");
+        goto err;
+      }
+
       if (flush_master_info(mi, 1))
       {
         sql_print_error("Failed to flush master info file");
@@ -2750,6 +2796,7 @@ err:
   // print the current replication position
   sql_print_information("Slave I/O thread exiting, read up to log '%s', position %s",
                   IO_RPL_LOG_NAME, llstr(mi->master_log_pos,llbuff));
+  RUN_HOOK(binlog_relay_io, thread_stop, (thd, mi));
   thd->set_query(NULL, 0);
   thd->reset_db(NULL, 0);
   if (mysql)
@@ -3906,6 +3953,71 @@ static int safe_reconnect(THD* thd, MYSQL* mysql, Master_info* mi,
 }
 
 
+MYSQL *rpl_connect_master(MYSQL *mysql)
+{
+  THD *thd= current_thd;
+  Master_info *mi= my_pthread_getspecific_ptr(Master_info*, RPL_MASTER_INFO);
+  if (!mi)
+  {
+    sql_print_error("'rpl_connect_master' must be called in slave I/O thread context.");
+    return NULL;
+  }
+
+  bool allocated= false;
+  
+  if (!mysql)
+  {
+    if(!(mysql= mysql_init(NULL)))
+    {
+      sql_print_error("rpl_connect_master: failed in mysql_init()");
+      return NULL;
+    }
+    allocated= true;
+  }
+
+  /*
+    XXX: copied from connect_to_master, this function should not
+    change the slave status, so we cannot use connect_to_master
+    directly
+    
+    TODO: make this part a seperate function to eliminate duplication
+  */
+  mysql_options(mysql, MYSQL_OPT_CONNECT_TIMEOUT, (char *) &slave_net_timeout);
+  mysql_options(mysql, MYSQL_OPT_READ_TIMEOUT, (char *) &slave_net_timeout);
+
+#ifdef HAVE_OPENSSL
+  if (mi->ssl)
+  {
+    mysql_ssl_set(mysql,
+                  mi->ssl_key[0]?mi->ssl_key:0,
+                  mi->ssl_cert[0]?mi->ssl_cert:0,
+                  mi->ssl_ca[0]?mi->ssl_ca:0,
+                  mi->ssl_capath[0]?mi->ssl_capath:0,
+                  mi->ssl_cipher[0]?mi->ssl_cipher:0);
+    mysql_options(mysql, MYSQL_OPT_SSL_VERIFY_SERVER_CERT,
+                  &mi->ssl_verify_server_cert);
+  }
+#endif
+
+  mysql_options(mysql, MYSQL_SET_CHARSET_NAME, default_charset_info->csname);
+  /* This one is not strictly needed but we have it here for completeness */
+  mysql_options(mysql, MYSQL_SET_CHARSET_DIR, (char *) charsets_dir);
+
+  if (io_slave_killed(thd, mi)
+      || !mysql_real_connect(mysql, mi->host, mi->user, mi->password, 0,
+                             mi->port, 0, 0))
+  {
+    if (!io_slave_killed(thd, mi))
+      sql_print_error("rpl_connect_master: error connecting to master: %s (server_error: %d)",
+                      mysql_error(mysql), mysql_errno(mysql));
+    
+    if (allocated)
+      mysql_close(mysql);                       // this will free the object
+    return NULL;
+  }
+  return mysql;
+}
+
 /*
   Store the file and position where the execute-slave thread are in the
   relay log.

sql/sql_class.cc

@@ -277,6 +277,42 @@ const char *set_thd_proc_info(THD *thd, const char *info,
   return old_info;
 }
 
+extern "C"
+const char* thd_enter_cond(MYSQL_THD thd, pthread_cond_t *cond,
+                           pthread_mutex_t *mutex, const char *msg)
+{
+  if (!thd)
+    thd= current_thd;
+
+  const char* old_msg = thd->proc_info;
+  safe_mutex_assert_owner(mutex);
+  thd->mysys_var->current_mutex = mutex;
+  thd->mysys_var->current_cond = cond;
+  thd->proc_info = msg;
+  return old_msg;
+}
+
+extern "C"
+void thd_exit_cond(MYSQL_THD thd, const char *old_msg)
+{
+  if (!thd)
+    thd= current_thd;
+
+  /*
+    Putting the mutex unlock in thd_exit_cond() ensures that
+    mysys_var->current_mutex is always unlocked _before_ mysys_var->mutex is
+    locked (if that would not be the case, you'll get a deadlock if someone
+    does a THD::awake() on you).
+  */
+  pthread_mutex_unlock(thd->mysys_var->current_mutex);
+  pthread_mutex_lock(&thd->mysys_var->mutex);
+  thd->mysys_var->current_mutex = 0;
+  thd->mysys_var->current_cond = 0;
+  thd->proc_info = old_msg;
+  pthread_mutex_unlock(&thd->mysys_var->mutex);
+  return;
+}
+
 extern "C"
 void **thd_ha_data(const THD *thd, const struct handlerton *hton)
 {

sql/sql_class.h

@@ -22,6 +22,7 @@
 
 #include "log.h"
 #include "rpl_tblmap.h"
+#include "replication.h"
 
 /**
   An interface that is used to take an action when
@@ -1940,27 +1941,11 @@ public:
   inline const char* enter_cond(pthread_cond_t *cond, pthread_mutex_t* mutex,
 			  const char* msg)
   {
-    const char* old_msg = proc_info;
-    safe_mutex_assert_owner(mutex);
-    mysys_var->current_mutex = mutex;
-    mysys_var->current_cond = cond;
-    proc_info = msg;
-    return old_msg;
+    return thd_enter_cond(this, cond, mutex, msg);
   }
   inline void exit_cond(const char* old_msg)
   {
-    /*
-      Putting the mutex unlock in exit_cond() ensures that
-      mysys_var->current_mutex is always unlocked _before_ mysys_var->mutex is
-      locked (if that would not be the case, you'll get a deadlock if someone
-      does a THD::awake() on you).
-    */
-    pthread_mutex_unlock(mysys_var->current_mutex);
-    pthread_mutex_lock(&mysys_var->mutex);
-    mysys_var->current_mutex = 0;
-    mysys_var->current_cond = 0;
-    proc_info = old_msg;
-    pthread_mutex_unlock(&mysys_var->mutex);
+    thd_exit_cond(this, old_msg);
   }
   inline time_t query_start() { query_start_used=1; return start_time; }
   inline void set_time()

sql/sql_parse.cc

@@ -21,6 +21,7 @@
 #include <m_ctype.h>
 #include <myisam.h>
 #include <my_dir.h>
+#include "rpl_handler.h"
 
 #include "sp_head.h"
 #include "sp.h"

sql/sql_plugin.cc

@@ -19,14 +19,6 @@
 #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[];
 
 /**
@@ -54,7 +46,8 @@ const LEX_STRING plugin_type_names[MYSQL_MAX_PLUGIN_TYPE_NUM]=
   { C_STRING_WITH_LEN("STORAGE ENGINE") },
   { C_STRING_WITH_LEN("FTPARSER") },
   { C_STRING_WITH_LEN("DAEMON") },
-  { C_STRING_WITH_LEN("INFORMATION SCHEMA") }
+  { C_STRING_WITH_LEN("INFORMATION SCHEMA") },
+  { C_STRING_WITH_LEN("REPLICATION") },
 };
 
 extern int initialize_schema_table(st_plugin_int *plugin);
@@ -93,7 +86,8 @@ static int min_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
   MYSQL_HANDLERTON_INTERFACE_VERSION,
   MYSQL_FTPARSER_INTERFACE_VERSION,
   MYSQL_DAEMON_INTERFACE_VERSION,
-  MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION
+  MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION,
+  MYSQL_REPLICATION_INTERFACE_VERSION,
 };
 static int cur_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
 {
@@ -101,7 +95,8 @@ static int cur_plugin_info_interface_version[MYSQL_MAX_PLUGIN_TYPE_NUM]=
   MYSQL_HANDLERTON_INTERFACE_VERSION,
   MYSQL_FTPARSER_INTERFACE_VERSION,
   MYSQL_DAEMON_INTERFACE_VERSION,
-  MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION
+  MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION,
+  MYSQL_REPLICATION_INTERFACE_VERSION,
 };
 
 static bool initialized= 0;

sql/sql_plugin.h

@@ -18,6 +18,14 @@
 
 class sys_var;
 
+#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
+
 /*
   the following flags are valid for plugin_init()
 */