On Fri, Aug 02, 2002 at 10:59:18PM +0200, Georg Richter wrote: > On Friday, 2. August 2002 20:48, Shane Allen wrote: > > I digress... at this point, the question that plagues me is: Is it normal > > for MySQL to die under high load? > > you have a lot of programs, which prefer to die under heavy load. The main > question is not why they die, the question is why is the load so high? > > I hope you already analyzed your system, your mysql-server and your queries > and can could give us some more additional information.
Well, most programs, in my experience, will keep running, even if load is 200, they just run slowly since they aren't getting processor load. As for why things are busy on the box, well, we run a fairly popular site... we have a primary database server that handles a large majority of our queries. Discussions about setting up a cluster or some other such thing aside, this server handles something to the tune of 3000 queries every five minutes during our off hours. During peak times, it's hit over 100k queries in five minutes, where quires == selects + updates + inserts, etc. We have spent a good deal of time lately optimizing what few queries were not already as good as they can be, but because of the large amounts of data we're dealing with, we sometimes join across 5 tables -- not much we can do about that. We're also performing a fairly extensive audit of our processes to reduce the number of necessary queries. We're also running MySQL databases on all of our front-end webservers that store non-changing data, like ISO country codes and such. All these things are intended to keep the load as low as possible. So, clustering aside (it's not an option right now), I am concerned about why MySQL dies... syslog and ntpd, for example, doesn't die under high load. On our front-end webservers, neither Apache nor cron die. So why is MySQL dying? Which takes me back to my original set of questions... The gentleman on PHPBuilder (http://www.phpbuilder.com/columns/tim20000705.php3) (again, I acknowledge this is an old article) says flat out that MySQL tends to die under high load. Also, when I say high load, I am talking 15-30. I have yet to see an application (other than MySQL when it's loaded down with queries) die under this level of load. So, if there is additional information that you would like in order to help us solve this problem, I will be happy to provide it. What would you like to know. Again, thanks in advance for any help you can provide. -- Shane Allen <[EMAIL PROTECTED]> --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
