On Tue, Aug 28, 2012 at 6:40 PM, Rick James <rja...@yahoo-inc.com> wrote: >> | Qcache_hits | 56418967 | >> | Qcache_inserts | 48601636 | > That's a low hit rate. Perhaps you should simply turn off the Query cache? > >> | Qcache_free_memory | 46945512 | > That's a big fraction of the total. Either the QC is unnecessarily big, or > it was recently purged.
It hasn't been purged resultly AFAIK. > >> | Qcache_lowmem_prunes | 21948806 | > What is Uptime? This may be a lot of prunes per second. Uptime is 65days, resulting in a little less than 4 per second. > > Purging stuff out of 128MB _may_ slow your system down more than the benefit > you are getting. > I recommend turning off the QC for systems with constant write activity. > Otherwise, 50M is a reasonable max. Thanks for your feedback. These question were going to be the topic of my next mail to the list, but you anticipated correctly :-) Raph > >> -----Original Message----- >> From: raphi...@gmail.com [mailto:raphi...@gmail.com] On Behalf Of >> Raphael Bauduin >> Sent: Tuesday, August 28, 2012 7:12 AM >> To: mysql@lists.mysql.com >> Subject: qcache settings and block meaning >> >> Hi, >> >> I have a mysql server running with the query cache size being 128M >> (134217728 bytes). >> >> Here are the qcache variables values: >> >> | Qcache_free_blocks | 13758 | >> | Qcache_free_memory | 46945512 | >> | Qcache_hits | 56418967 | >> | Qcache_inserts | 48601636 | >> | Qcache_lowmem_prunes | 21948806 | >> | Qcache_not_cached | 39066097 | >> | Qcache_queries_in_cache | 44858 | >> | Qcache_total_blocks | 104668 >> >> And the query_cache_min_res_unit is 4096 . >> >> I'm not sure what the meaning of a block is. For the query cache size >> and the number of total blocks, I have a block size of >> 134217728/104668 = 1282.3186 , which is a strange number for a block >> size. Am I wrong somewhere? >> >> Thanks >> >> Raph >> >> -- >> MySQL General Mailing List >> For list archives: http://lists.mysql.com/mysql >> To unsubscribe: http://lists.mysql.com/mysql > -- Web database: http://www.myowndb.com Free Software Developers Meeting: http://www.fosdem.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
