On Thu, Sep 24, 2009 at 9:11 AM, Jay Pipes <[email protected]> wrote: > Hi Mark! > > Is there a reason you are using the pool_of_threads scheduler in Drizzle? > Is this a requirement on your end? We've found that the pool_of_threads > scheduler has serious performance problems and we recommend using the > default multi_thread scheduler. In addition, to get an apples-to-apples > comparison, I would advise using multi_thread, as MySQL < 6.0 does not have > a pool of threads scheduler anyway.
I wasn't using pool-of-threads. It took me a while today to figure out how to use pool-of-threads today. It turns out that the results I reported were for multi-thread. SHOW VARIABLES doesn't report the value for scheduler, so I was uncertain about which scheduler was used. This lists the number of seconds for 16 concurrent sessions to each run 1M statements: 129 -- 5.1.38 + innodb plugin 1.0.4 + latin1 139 -- 5.1.38 + innodb plugin 1.0.4 + utf8 130 -- 5.1.38 + innodb builtin + latin1 162 -- drizzle + innodb plugin 1.03 + utf8 Times for pool-of-threads are much worse. I won't report them here as I don't think this workload is a good fit for pool-of-threads. > > In addition, you will see serious performance bottlenecks if TCMalloc is > installed on your benchmark server. MySQL's memory allocation procedures > simply do not like TCMalloc. Or you used a slow & old version of tcmalloc as Domas has suggested on your blog. http://jpipes.com/index.php?/archives/296-Drizzle-Performance-Regression-Solved-TCMalloc-vs.-No-TCMalloc.html I did not use tcmalloc in this case. At my previous employer, performance with tcmalloc was always much better than without. At my current employer I use a different version of Linux and tcmalloc doesn't improve things. I have yet to see it make things worse. -- Mark Callaghan [email protected] _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
