On Tuesday, February 8, 2005, 3:20:25 PM, Bill wrote: BGdS> I have started seeing this line repeated in the persistent sniffer command BGdS> window.
BGdS> ERROR_LOGFILE: Bad Lock During Logging BGdS> c:\imail\declude\sniffer\"mycode".log BGdS> It looks like the error has been happening once a day for about a week. BGdS> Other than the message all seems to be working well. Where should I look for BGdS> the cause? The first clue I can see is that it happens once per day... Chances are there is a scheduled process interfering with the log file, the storage system in general (perhaps some backups or other IO intensive operation). Locking is a very lightweight mechanism in SNF because most operations are synchronized and sequential. If you are only seeing one of these per day then there is no cause to worry - but do keep an eye on it so that it doesn't get worse without you knowing it. A bad lock is probably a stale lock file --- The protocol would be to simply ignore the lock after waiting the appropriate amount of time. In theory, no lock should be required to write to the log file because it is opened in "append" mode. Unfortunately on Win32 based systems this doesn't mean what it should. That is, write operations are not 'atomic' --- so if more than one process tries to append to the log file at once the result is unpredictable corruption. The locking mechanism we're using here (creating a lock semaphore file) is only intended to synchronize access to the file since Win32 doesn't. The fact that one process will wait - even if the lock fails - usually accomplishes this task. If the process were to fail and two processes wrote (append) to the log file at once then it is possible, but not certain, that log corruption would occur -- which is not strictly vital for the odd record here and there. Hope this helps, _M This E-Mail came from the Message Sniffer mailing list. For information and (un)subscription instructions go to http://www.sortmonster.com/MessageSniffer/Help/Help.html
