On Mon, 7 Jun 2004, Haitao Jiang wrote: > Marc > > mysqld runs on a very powerful Operton machine with > 16GB memory and barely any other application process > running, it is hard to believe that a simple select > that runs under 2 second will utilize all the > resources...that is why I tend to think there is > something in the mysql set up that caused this...any > idea where I should look?
How many processors? If there is only one and the query is CPU bound (as it probably is if everything is cached, given 16 gigs of ram), then why shouldn't it use all the CPU? Or, to phrase the question differently: why should the query take 2 seconds to run if there are free resources? Now, on a multiprocessor box it clearly starts to get more complicated. mysql has no capability to spread one query across multiple CPUs in parallel, and while it can spread multiple queries across CPUs the scalability has its limits. The fact that is a "simple query" is irrelevant (some of the simplest can be the slowest if it has to do a full table scan). From the fact that it takes 2 seconds it is clear it is not an entirely trivial query. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
