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i noticed that my server acting slow, and also found that mysql is using a lot of memory - 423.1 MB free of 3.9 GB...

after i restarted mysql it was 3.8 GB free of 3.9 GB.

few minutes after, it was 2.5 GB free of 3.9 GB.

where can be a problem? it is centos, with mysql 5.1.

thank you in advance!

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There may not be a problem. We need more information. Can you provide the output from free -m, for starters? – Christopher Cashell Nov 1 '10 at 20:44
I don't think this is a problem in and of itself. Unused memory is memory you wasted money on purchasing. – RobM Nov 1 '10 at 20:55

If configured to (I would say configured correctly) MySQL will use as much memory as you give it to cache data, query plans, result sets, etc. Every byte it caches in memory is a byte that it doesn't have to go to the disk for. So high memory utilization should be a good thing.

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Despite how simple this is, that's actually pretty profound. I've been freaking about the memory usage on my server being really high, but I had never considered that that was most efficient... – Hartley Brody Jan 27 '12 at 23:52

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