Bug#7011

  Fix replication for multi-update
  new test - rpl_multi_update2


sql/mysql_priv.h:
  Bug#7011
    New function mysql_multi_update_lock()
sql/sql_parse.cc:
  Bug#7011
    New function check_multi_update_lock()
    For multi-update on slave, perform an early open&lock
sql/sql_update.cc:
  Bug#7011
    Split out multi-update locking into its own function,
      mysql_multi_update_lock()

mysql-test/r/rpl_multi_update2.result

+slave stop;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+slave start;
+CREATE TABLE t1 (
+a int unsigned not null auto_increment primary key,
+b int unsigned
+) TYPE=MyISAM;
+CREATE TABLE t2 (
+a int unsigned not null auto_increment primary key,
+b int unsigned
+) TYPE=MyISAM;
+INSERT INTO t1 VALUES (NULL, 0);
+INSERT INTO t1 SELECT NULL, 0 FROM t1;
+INSERT INTO t2 VALUES (NULL, 0), (NULL,1);
+SELECT * FROM t1 ORDER BY a;
+a	b
+1	0
+2	0
+SELECT * FROM t2 ORDER BY a;
+a	b
+1	0
+2	1
+UPDATE t1, t2 SET t1.b = (t2.b+4) WHERE t1.a = t2.a;
+SELECT * FROM t1 ORDER BY a;
+a	b
+1	4
+2	5
+SELECT * FROM t2 ORDER BY a;
+a	b
+1	0
+2	1
+SELECT * FROM t1 ORDER BY a;
+a	b
+1	4
+2	5
+SELECT * FROM t2 ORDER BY a;
+a	b
+1	0
+2	1

mysql-test/t/rpl_multi_update2-slave.opt

+--replicate-ignore-table=nothing.sensible

mysql-test/t/rpl_multi_update2.test

+# Let's verify that multi-update is not always skipped by slave if
+# some replicate-* rules exist.
+# (BUG#7011)
+
+source include/master-slave.inc;
+
+CREATE TABLE t1 (
+ a int unsigned not null auto_increment primary key,
+ b int unsigned
+) TYPE=MyISAM;
+
+CREATE TABLE t2 (
+ a int unsigned not null auto_increment primary key,
+ b int unsigned
+) TYPE=MyISAM;
+
+INSERT INTO t1 VALUES (NULL, 0);
+INSERT INTO t1 SELECT NULL, 0 FROM t1;
+
+INSERT INTO t2 VALUES (NULL, 0), (NULL,1);
+
+SELECT * FROM t1 ORDER BY a;
+SELECT * FROM t2 ORDER BY a;
+
+UPDATE t1, t2 SET t1.b = (t2.b+4) WHERE t1.a = t2.a;
+SELECT * FROM t1 ORDER BY a;
+SELECT * FROM t2 ORDER BY a;
+
+save_master_pos;
+connection slave;
+sync_with_master;
+SELECT * FROM t1 ORDER BY a;
+SELECT * FROM t2 ORDER BY a;

sql/mysql_priv.h

@@ -469,6 +469,9 @@ int mysql_update(THD *thd,TABLE_LIST *tables,List<Item> &fields,
 		 List<Item> &values,COND *conds, 
                  ORDER *order, ha_rows limit,
 		 enum enum_duplicates handle_duplicates);
+int mysql_multi_update_lock(THD *thd,
+			    TABLE_LIST *table_list,
+			    List<Item> *fields);
 int mysql_multi_update(THD *thd, TABLE_LIST *table_list,
 		       List<Item> *fields, List<Item> *values,
 		       COND *conds, ulong options,

sql/sql_parse.cc

@@ -56,6 +56,8 @@ static int check_for_max_user_connections(USER_CONN *uc);
 static void decrease_user_connections(USER_CONN *uc);
 static bool check_db_used(THD *thd,TABLE_LIST *tables);
 static bool check_merge_table_access(THD *thd, char *db, TABLE_LIST *tables);
+static bool check_multi_update_lock(THD *thd, TABLE_LIST *tables, 
+				    List<Item> *fields);
 static void mysql_init_query(THD *thd);
 static void remove_escape(char *name);
 static void refresh_status(void);
@@ -1338,10 +1340,28 @@ mysql_execute_command(void)
   LEX	*lex= &thd->lex;
   TABLE_LIST *tables=(TABLE_LIST*) lex->select_lex.table_list.first;
   SELECT_LEX *select_lex = lex->select;
+  bool slave_fake_lock= 0;
+  MYSQL_LOCK *fake_prev_lock= 0;
   DBUG_ENTER("mysql_execute_command");
 
   if (thd->slave_thread)
   {
+    if (lex->sql_command == SQLCOM_MULTI_UPDATE)
+    {
+      DBUG_PRINT("info",("need faked locked tables"));
+      
+      if (check_multi_update_lock(thd, tables, &select_lex->item_list))
+        goto error;
+
+      /* Fix for replication, the tables are opened and locked,
+         now we pretend that we have performed a LOCK TABLES action */
+	 
+      fake_prev_lock= thd->locked_tables;
+      if (thd->lock)
+        thd->locked_tables= thd->lock;
+      thd->lock= 0;
+      slave_fake_lock= 1;
+    }
     /* 
       Skip if we are in the slave thread, some table rules have been
       given and the table list says the query should not be replicated
@@ -1949,7 +1969,7 @@ mysql_execute_command(void)
     if (select_lex->item_list.elements != lex->value_list.elements)
     {
       send_error(&thd->net,ER_WRONG_VALUE_COUNT);
-      DBUG_VOID_RETURN;
+      goto error;
     }
     {
       const char *msg= 0;
@@ -2641,6 +2661,14 @@ mysql_execute_command(void)
     send_error(&thd->net,thd->killed ? ER_SERVER_SHUTDOWN : 0);
 
 error:
+  if (unlikely(slave_fake_lock))
+  {
+    DBUG_PRINT("info",("undoing faked lock"));
+    thd->lock= thd->locked_tables;
+    thd->locked_tables= fake_prev_lock;
+    if (thd->lock == thd->locked_tables)
+      thd->lock= 0;
+  }
   DBUG_VOID_RETURN;
 }
 
@@ -3907,3 +3935,54 @@ bool check_simple_select()
   }
   return 0;
 }
+
+/*
+  Setup locking for multi-table updates. Used by the replication slave.
+  Replication slave SQL thread examines (all_tables_not_ok()) the
+  locking state of referenced tables to determine if the query has to
+  be executed or ignored. Since in multi-table update, the 
+  'default' lock is read-only, this lock is corrected early enough by
+  calling this function, before the slave decides to execute/ignore.
+
+  SYNOPSIS
+    check_multi_update_lock()
+    thd		Current thread
+    tables	List of user-supplied tables
+    fields	List of fields requiring update
+
+  RETURN VALUES
+    0	ok
+    1	error
+*/
+static bool check_multi_update_lock(THD *thd, TABLE_LIST *tables, 
+				    List<Item> *fields)
+{
+  bool res= 1;
+  TABLE_LIST *table;
+  DBUG_ENTER("check_multi_update_lock");
+  
+  if (check_db_used(thd, tables))
+    goto error;
+
+  /*
+    Ensure that we have UPDATE or SELECT privilege for each table
+    The exact privilege is checked in mysql_multi_update()
+  */
+  for (table= tables ; table ; table= table->next)
+  {
+    TABLE_LIST *save= table->next;
+    table->next= 0;
+    if (check_one_table_access(thd, UPDATE_ACL, table, 1) &&
+	check_one_table_access(thd, SELECT_ACL, table, 0))
+	goto error;
+    table->next= save;
+  }
+    
+  if (mysql_multi_update_lock(thd, tables, fields))
+    goto error;
+  
+  res= 0;
+  
+error:
+  DBUG_RETURN(res);
+}

sql/sql_update.cc

@@ -403,26 +403,20 @@ static table_map get_table_map(List<Item> *items)
 }
 
 
-
 /*
-  Setup multi-update handling and call SELECT to do the join
+  Prepare tables for multi-update 
+  Analyse which tables need specific privileges and perform locking
+  as required
 */
 
-int mysql_multi_update(THD *thd,
-		       TABLE_LIST *table_list,
-		       List<Item> *fields,
-		       List<Item> *values,
-		       COND *conds,
-		       ulong options,
-		       enum enum_duplicates handle_duplicates)
+int mysql_multi_update_lock(THD *thd,
+			    TABLE_LIST *table_list,
+			    List<Item> *fields)
 {
   int res;
-  multi_update *result;
   TABLE_LIST *tl;
   const bool using_lock_tables= thd->locked_tables != 0;
-  DBUG_ENTER("mysql_multi_update");
-
-  thd->select_limit= HA_POS_ERROR;
+  DBUG_ENTER("mysql_multi_update_lock");
 
   for (;;)
   {
@@ -490,7 +484,7 @@ int mysql_multi_update(THD *thd,
           (grant_option && check_grant(thd, wants, tl, 0, 0)))
       {
 	tl->next= save;
-	DBUG_RETURN(0);
+	DBUG_RETURN(1);
       }
       tl->next= save;
     }
@@ -498,11 +492,7 @@ int mysql_multi_update(THD *thd,
     /* Relock the tables with the correct modes */
     res= lock_tables(thd,table_list);
     if (using_lock_tables)
-    {
-      if (res)
-        DBUG_RETURN(res);
       break;                                 // Don't have to do setup_field()
-    }
 
     /*
       We must setup fields again as the file may have been reopened
@@ -535,6 +525,31 @@ int mysql_multi_update(THD *thd,
     */
     close_thread_tables(thd);
   }
+  
+  DBUG_RETURN(res);
+}
+
+/*
+  Setup multi-update handling and call SELECT to do the join
+*/
+
+int mysql_multi_update(THD *thd,
+		       TABLE_LIST *table_list,
+		       List<Item> *fields,
+		       List<Item> *values,
+		       COND *conds,
+		       ulong options,
+		       enum enum_duplicates handle_duplicates)
+{
+  int res;
+  TABLE_LIST *tl;
+  multi_update *result;
+  DBUG_ENTER("mysql_multi_update");
+
+  thd->select_limit= HA_POS_ERROR;
+
+  if ((res= mysql_multi_update_lock(thd, table_list, fields)))
+    DBUG_RETURN(res);
 
   /*
     Count tables and setup timestamp handling