bk commit into 5.1 tree (thek:1.2379) BUG#25422

[kpettersson]

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5.1 repository of thek. When thek does a push these changes will
be propagated to the main repository and, within 24 hours after the
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ChangeSet@stripped, 2007-02-13 18:25:43+01:00, thek@stripped +1 -0
  Bug#25422 Hang with log tables
  
  - Truncate table can dead lock
  - Moved mutex LOGGER:lock to include the table lock.

  sql/sql_delete.cc@stripped, 2007-02-13 18:25:40+01:00, thek@stripped +19 -5
    Bug#25422 Hang with log tables
    
    - Concurrent calls to mysql_truncate can dead lock on the
      LOGGER::lock and a named table lock.
    - Moved mutex LOGGER:lock to include the table lock which resolves 
      the dead lock.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	thek
# Host:	kpdesk.mysql.com
# Root:	/home/thek/dev/bug25422/my51-bug25422

--- 1.205/sql/sql_delete.cc	2007-02-13 18:25:50 +01:00
+++ 1.206/sql/sql_delete.cc	2007-02-13 18:25:50 +01:00
@@ -895,6 +895,15 @@ bool mysql_truncate(THD *thd, TABLE_LIST
   path_length= build_table_filename(path, sizeof(path), table_list->db,
                                     table_list->table_name, reg_ext, 0);
 
+  log_type= check_if_log_table(table_list->db_length, table_list->db,
+                               table_list->table_name_length,
+                               table_list->table_name, 1);
+  if (log_type)
+  {
+   lock_logger= 1;
+   logger.lock();
+  }
+
   if (!dont_send_ok)
   {
     enum legacy_db_type table_type;
@@ -903,24 +912,29 @@ bool mysql_truncate(THD *thd, TABLE_LIST
     {
       my_error(ER_NO_SUCH_TABLE, MYF(0),
                table_list->db, table_list->table_name);
+      if (lock_logger)
+        logger.unlock();
       DBUG_RETURN(TRUE);
     }
     if (!ha_check_storage_engine_flag(ha_resolve_by_legacy_type(thd, table_type),
                                       HTON_CAN_RECREATE))
+    {
+      if (lock_logger)
+        logger.unlock();
       goto trunc_by_del;
+    }
 
     if (lock_and_wait_for_table_name(thd, table_list))
+    {
+      if (lock_logger)
+        logger.unlock();
       DBUG_RETURN(TRUE);
+    }
   }
 
-  log_type= check_if_log_table(table_list->db_length, table_list->db,
-                               table_list->table_name_length,
-                               table_list->table_name, 1);
   /* close log tables in use */
   if (log_type)
   {
-    lock_logger= 1;
-    logger.lock();
     logger.close_log_table(log_type, FALSE);
     closed_log_tables= closed_log_tables | log_type;
   }