From: Date: July 29 2005 4:47pm Subject: Re: Complete server lock List-Archive: http://lists.mysql.com/mysql/187092 Message-Id: <42EA417E.60307@trusswood.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Ben Clewett wrote: > Jigal, > > Thanks. > > I can confirm that there were no domains used for our permissions. All > IP based. Although this may have been the cause, I don't think it was > in this case. I think as well that DNS timeouts are in the region of 20 > seconds to 2 minutes. > > Would any person know if there is any other part of MySQL which uses DNS > lookups? For instance, logging of some kind? > > Or any other reason a MySQL daemon would not respond to a kill? > > Thank for the ideas, > > Ben Clewett. > > > Jigal van Hemert wrote: > >> Ben Clewett wrote: >> >>> It had been suggested that our DNS failed prior to this event. I >>> don't think MySQL uses DNS, but I am not entirely sure. >> >> >> >> If the db, user, etc. tables in the mysql system database (containing >> privileges, etc.) contain host names instead of IP-addresses I suspect >> it needs a DNS to resolve these... >> >>> If I get a state where a 'kill' will not cause MySQL to exit. Is >>> there any other know way to ask MySQL to exit cleanly? >> >> >> >> MySQL server was probably waiting for a bunch of DNS requests? Until a >> timeout occurs it will probably keep the connection waiting. This can >> cause a lot of connections to occur until you reach max_connections at >> which point it will not accept new connections anymore. >> >> Regards, Jigal. >> > > I noticed, on my Linux server, that MySQL makes a DNS lookup anyway. Even if the IP is used or not. It normally digs on the PTR record. I had all of my perms IP based, however, it still looked at the PTR record. At the time I hadn't set any up in my DNS server. After I added all the PTR records of the clients that were connecting to the server, it was fast again. ...Something to think about... -- Thanks, James