What MySQL buffer cache hit rate should you target

“What cache hit rate is good for optimal MySQL Performance” is typical question I’m asked. It could by MyISAM key_buffer or Innodb innodb_buffer_pool it does not really matter. In both cases trying to come up with constant “good” hit rate is looking for trouble. Well of course you can name 100% hit […]

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FreeBSD tests

I’m continuing my experiments with different OS and today I tested FreeBSD 6.0 on my box.
(more details about box and benchmark see here https://www.percona.com/blog/2006/06/13/quick-look-at-ubuntu-606/).
Initially I was very pessimistic about FreeBSD, as results were (in transactions/sec, more is better.
for comparison the results from Suse 10.0):

InnoDB

threads
FreeBSD 6
Suse 10.0
Suse/ FreeBSD ratio

1
436.97
536.91
1.23

4
322.08
816.27
2.53

16
519.94
639.05
1.23

64
crash
547.07

256

357.09

MyISAM

threads
FreeBSD 6
Suse 10.0
Suse/ FreeBSD ratio

1
335.56
429.89
1.28

4
165.16
863.23
5.23

16
322.66
537.67
1.67

64
crash
516.00

256

346.65

The crash with […]

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MyISAM concurrent insert

Arjen posted a good note about MyISAM concurrent-insert features, though I should mention concurrent-insert can be cause of
scalablity and peformance problems on SMP boxes, especially on queries processing range-queries. The reason of problems is POSIX read-write locks, which are used to protect key_buffer from concurrent changes and called for each processed row. More info […]

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