Re: How to kill locked queries
On Thu, Oct 14, 2010 at 3:28 AM, Johan De Meersman wrote: > That depends on the type of lock. If no lock type is specified, InnDB will > prefer row locks, while MyISAM will do table locks. > > That may help, unless all your queries are trying to access the same rows > anyway :-) Even that can work without locking in InnoDB if only one query is trying to modify the rows. Unlike MyISAM, readers do not block writers in InnoDB and vice versa. - Perrin -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/mysql?unsub=arch...@jab.org
Re: How to kill locked queries
On Thu, Oct 14, 2010 at 9:19 AM, monloi perez wrote: > Does this happen if your table is InnoDB? > That depends on the type of lock. If no lock type is specified, InnDB will prefer row locks, while MyISAM will do table locks. That may help, unless all your queries are trying to access the same rows anyway :-) You really need to figure out *what* is being locked and *why* before you can fix it. -- Bier met grenadyn Is als mosterd by den wyn Sy die't drinkt, is eene kwezel Hy die't drinkt, is ras een ezel
Re: How to kill locked queries
Does this happen if your table is InnoDB? Thanks all, Mon From: Claudio Nanni To: monloi perez Cc: mysql mailing list Sent: Thu, October 14, 2010 3:16:38 PM Subject: Re: How to kill locked queries Hi Mon, Killing locked queries is not the first step in database tuning. Queries locked for a long time usually depend on slow updates that lock other updates or selects, this happen on MyISAM (or table level locking engines). If you are really sure you want and can without problems kill the queries you can do a simple job to check and kill. I would rather check why those queries are locked anyway. Aloha Claudio 2010/10/14 monloi perez All, > >Is there a mysql configuration to kill queries that have been locked for quite >some time. If there's none what is an alternative approach to kill these locked >queries and what is the root cause of it? > >Thanks, >Mon > > > -- Claudio
Re: How to kill locked queries
Hi Mon, Killing locked queries is not the first step in database tuning. Queries locked for a long time usually depend on slow updates that lock other updates or selects, this happen on MyISAM (or table level locking engines). If you are really sure you want and can without problems kill the queries you can do a simple job to check and kill. I would rather check why those queries are locked anyway. Aloha Claudio 2010/10/14 monloi perez > All, > > Is there a mysql configuration to kill queries that have been locked for > quite > some time. If there's none what is an alternative approach to kill these > locked > queries and what is the root cause of it? > > Thanks, > Mon > > > -- Claudio
Re: How to kill locked queries
The root cause is another query that has tables locked that your "locked" queries want. Behind that may be, for example, an inefficient but often-executed query, high I/O concurrency that has a cumulative slowing effect, or maybe simply a long-running update that might be better scheduled during the quiet hours. You can kill the "locked" queries, but it is likely that more will simply appear in their place. You can kill the evil monster query, but depending on what's actually going on it's quite possible that one of the waiting ones will take it's place as the resource hog. Sometimes a quick fix is to simply restart the service, if there's just too much competition for the same locks; but obviously the problem will just reappear later. What you need to do is figure out which query is holding the locks, and see if you can optimize and/or reschedule it. On Thu, Oct 14, 2010 at 9:01 AM, monloi perez wrote: > All, > > Is there a mysql configuration to kill queries that have been locked for > quite > some time. If there's none what is an alternative approach to kill these > locked > queries and what is the root cause of it? > > Thanks, > Mon > > > -- Bier met grenadyn Is als mosterd by den wyn Sy die't drinkt, is eene kwezel Hy die't drinkt, is ras een ezel
How to kill locked queries
All, Is there a mysql configuration to kill queries that have been locked for quite some time. If there's none what is an alternative approach to kill these locked queries and what is the root cause of it? Thanks, Mon
