On Tue, Aug 28, 2012 at 6:40 PM, Rick James <rjames@stripped> 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: raphinou@stripped [mailto:raphinou@stripped] On Behalf Of
>> Raphael Bauduin
>> Sent: Tuesday, August 28, 2012 7:12 AM
>> To: mysql@stripped
>> 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
