Backport of:

------------------------------------------------------------
revno: 2630.4.27
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Mon 2008-06-09 14:01:19 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress.

  Changed open_table() to return bool. This allows more easily to
  distinguish cases when this function succeeds but returns no TABLE
  instance (in case of view or in case of special kind of open) from
  cases when we have an error. Pointer to TABLE instance is now
  always returned in TABLE_LIST::table member.

  This change allows to get rid of false assumption in open_tables()
  implementation and makes it more clear.

sql/mysql_priv.h

@@ -1220,8 +1220,8 @@ TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
                    uint lock_flags);
 enum enum_open_table_action {OT_NO_ACTION= 0, OT_BACK_OFF_AND_RETRY,
                              OT_DISCOVER, OT_REPAIR};
-TABLE *open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT* mem,
-		  enum_open_table_action *action, uint flags);
+bool open_table(THD *thd, TABLE_LIST *table_list, MEM_ROOT* mem,
+                enum_open_table_action *action, uint flags);
 bool tdc_open_view(THD *thd, TABLE_LIST *table_list, const char *alias,
                    char *cache_key, uint cache_key_length,
                    MEM_ROOT *mem_root, uint flags);

sql/sql_insert.cc

@@ -3555,8 +3555,8 @@ static TABLE *create_table_from_items(THD *thd, HA_CREATE_INFO *create_info,
       }
       else
       {
-        if (!(table= open_table(thd, create_table, thd->mem_root, &not_used2,
-                                MYSQL_OPEN_TEMPORARY_ONLY)) &&
+        if (open_table(thd, create_table, thd->mem_root, &not_used2,
+                       MYSQL_OPEN_TEMPORARY_ONLY) &&
             !create_info->table_existed)
         {
           /*
@@ -3566,6 +3566,8 @@ static TABLE *create_table_from_items(THD *thd, HA_CREATE_INFO *create_info,
           */
           drop_temporary_table(thd, create_table);
         }
+        else
+          table= create_table->table;
       }
     }
     reenable_binlog(thd);

sql/sql_table.cc

@@ -7182,8 +7182,9 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
       tbl.db= new_db;
       tbl.table_name= tbl.alias= tmp_name;
       /* Table is in thd->temporary_tables */
-      new_table= open_table(thd, &tbl, thd->mem_root, &not_used,
-                            MYSQL_LOCK_IGNORE_FLUSH);
+      (void) open_table(thd, &tbl, thd->mem_root, &not_used,
+                        MYSQL_LOCK_IGNORE_FLUSH);
+      new_table= tbl.table;
     }
     else
     {