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using the mysql workbench administrator - my key efficiency is at 99.97% i have read about adding 'key_cache_size=100M' to my.cnf and increasing it as needed

is this the correct fix for the problem? im runing server 5.5.11 on server 2008 r2 , 24gb ram

thanks!

Jeff
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1 Answers1

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That's actually remarkably good - the higher the better.

The MySQL performance is good if the value of Key Read Efficiency is 90 percent and above

http://www.webnms.com/mysql_agent/help/mysql_agent/performance.html

Eduardo Ivanec
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  • oh well that saves me a dramatic headache - i was reading this and wasn't sure http://dev.mysql.com/doc/administrator/en/mysql-administrator-health-memory-health.html – Jeff May 04 '11 at 18:36
  • here is another question for you, how high is the query cache hitrate supposed to be? mine is at 42.88% – Jeff May 04 '11 at 18:38
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    The cache hit rate depends highly on the application running against the DB. If you control the application, you should be able to get a very high hit rate. If you don't, (and it is poorly written), you can expect some really low values. – Ryaner May 04 '11 at 18:44
  • @Ryaner what in an application determines the hit rate? like --- not closing connections properly, repetitive connections, etc.? – Jeff May 04 '11 at 18:47
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    That's nothing to worry about if I remember correctly. You can read on about that on http://www.mysqlperformanceblog.com/2006/07/27/mysql-query-cache/ – Eduardo Ivanec May 04 '11 at 18:47
  • So does the high utilization of cache mean that everything that needs to be cached is cached? Or does it mean it's working well for what it's got, but it's maxed out and it needs more? – Marcin May 04 '11 at 18:50
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    I'm not expert on this, but in my opinion a good although very basic methodology for cache sizing (specially when the problem is so relative to the app) seems to be: increase it, for example 2x, and see how much the metric you're analizing improves. – Eduardo Ivanec May 04 '11 at 18:52