Bug#7879: Using TL_READ_NO_INSERT locks instead of TL_READ locks when

reading tables in "complex" SQL statements. If inserts happen in a
table being read, the statements have no serialization order and the
change can therefore not be reproduced on the slave.

sql/sql_update.cc

@@ -479,7 +479,10 @@ int mysql_multi_update(THD *thd,
       else
       {
 	DBUG_PRINT("info",("setting table `%s` for read-only", tl->alias));
-	tl->lock_type= TL_READ;
+	// If we are using the binary log, we need TL_READ_NO_INSERT to get
+	// correct order of statements. Otherwise, we use a TL_READ lock to
+	// improve performance.
+	tl->lock_type= using_update_log ? TL_READ_NO_INSERT : TL_READ;
 	tl->updating= 0;
 	wants= SELECT_ACL;
       }

sql/sql_yacc.yy

@@ -822,7 +822,7 @@ create_select:
           SELECT_SYM
           {
 	    LEX *lex=Lex;
-	    lex->lock_option= (using_update_log) ? TL_READ_NO_INSERT : TL_READ;
+	    lex->lock_option= using_update_log ? TL_READ_NO_INSERT : TL_READ;
 	    if (lex->sql_command == SQLCOM_INSERT)
 	      lex->sql_command= SQLCOM_INSERT_SELECT;
 	    else if (lex->sql_command == SQLCOM_REPLACE)