When more than one -n option or -s option is specified in the command line, dbmlsync may experience fragmentation which results in discarded memory. The discarded memory can be recovered by rescanning the database transaction log. This hook allows you to decide if dbmlsync should rescan the database transaction log to recover memory.

When no other condition has been met that would force a rescan, this hook is called immediately after the sp_hook_dbmlsync_process_exit_code hook.

Hook procedures can be created by any user with the MANAGE REPLICATION system privilege. However, to ensure that the hook can access the #hook_dict table, which is used to pass information in and out of hooks, hooks must meet one of the following requirements:

• HoverRescanThreshold (hrt) extended option

The following example cause a log scan if the discarded storage is greater than 1000 bytes.

CREATE PROCEDURE sp_hook_dbmlsync_log_rescan ()
BEGIN
 IF EXISTS(SELECT * FROM #hook_dict
  WHERE name = 'Discarded storage' AND value>1000)
 THEN
  UPDATE #hook_dict SET value ='true' WHERE name='Rescan';
 END IF;
END;