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From:Reindl Harald Date:April 25 2011 2:29pm
Subject:Re: Memory Usage.
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Am 25.04.2011 16:24, schrieb Andrés Tello:
> How can I know how memory is being used by Mysql?
> I have 32GB Ram, but I can't make mysql to use more than 12GB Ram , and even
> that I have tables over 40GB...
> Thanks! xD

depends on storage-engine (myisam or innodb), buffer-sizes, size
of the query-cache, size of keys - the target is not to use the
full memory, the target is use available momory wise

search for ""

very interesting is the memory per connection (depends on many buffer-params)
becuase with a little mistake the possible max usage can easily be some
hundret GB!

[--] Up for: 17d 21h 53m 13s (39M q [25.329 qps], 132K conn, TX: 60B, RX: 19B)
[--] Reads / Writes: 67% / 33%
[--] Total buffers: 6.1G global + 1.2M per thread (500 max threads)
[OK] Maximum possible memory usage: 6.7G (66% of installed RAM)
[OK] Slow queries: 0% (13/39M)
[OK] Highest usage of available connections: 72% (362/500)
[OK] Key buffer size / total MyISAM indexes: 128.0M/74.1M
[OK] Key buffer hit rate: 97.6% (109M cached / 2M reads)
[OK] Query cache efficiency: 73.8% (23M cached / 32M selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (247 temp sorts / 731K sorts)
[OK] Temporary tables created on disk: 0% (1K on disk / 1M total)
[OK] Thread cache hit rate: 99% (362 created / 132K connections)
[!!] Table cache hit rate: 8% (131 open / 1K opened)
[OK] Open file limit used: 0% (67/30K)
[OK] Table locks acquired immediately: 99% (18M immediate / 18M locks)
[!!] InnoDB data size / buffer pool: 16.6G/5.0G


Mit besten Grüßen, Reindl Harald
the lounge interactive design GmbH
A-1060 Vienna, Hofmühlgasse 17
CTO / software-development / cms-solutions
p: +43 (1) 595 3999 33, m: +43 (676) 40 221 40
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Memory Usage.AndrĂ©s Tello25 Apr
  • Re: Memory Usage.Reindl Harald25 Apr
  • RE: Memory Usage.Jerry Schwartz25 Apr