by williamconley » Sat May 25, 2013 10:51 pm
query caching is not pointless. while it is true that the data changes "so often" from a human standpoint, the data is also requested very often. often several times per second by different processes. keeping that data in memory dramatically reduces the need to read.
the most "optimized" my.cnf is based on your usage. my.cnf optimized for a pure DB server in a cluster is what is installed by Vicibox.com's .iso if you tell the wizard to install only mysql on that server.
that being said, if you find demonstrable improvements in performance by modifying your my.cnf, feel free to post your configuration, usage, and my.cnf settings that helped with your particular configuration. and of course the observation that made you certain it was an improvement.
by improvement in performance, i don't refer to something that "may" indicate an improvement, though. there have been those who believed that having more memory available was an improvement ... so they turned off caching. since caching was no longer eating memory ... they had memory available. but upon deeper inspection ... a heavy load killed the server much earlier. because caching was not able to assist with the reduction in read/write. and mysql caching may appear to eat memory, but that memory is actually marked as "free". if it gets used by another process, mysql will simply collect that information from disk ... if not, it will recycle it from the cache. so killing it all immediately merely means the mysql process must re-read this information from the HD. more i/o = faster death if your i/o system ever becomes overloaded (which can happen on a mysql server).
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