> It hasn't been purged resultly ('recently'?) AFAIK. Purging happens automatically -- Whenever ANY change is made to a table, ALL entries in the QC for that table are purged.
> -----Original Message----- > From: raphi...@gmail.com [mailto:raphi...@gmail.com] On Behalf Of > Raphael Bauduin > Sent: Wednesday, August 29, 2012 2:16 AM > To: Rick James > Cc: mysql@lists.mysql.com > Subject: Re: qcache settings and block meaning > > 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