> 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: [email protected] [mailto:[email protected]] On Behalf Of
> Raphael Bauduin
> Sent: Wednesday, August 29, 2012 2:16 AM
> To: Rick James
> Cc: [email protected]
> Subject: Re: qcache settings and block meaning
>
> On Tue, Aug 28, 2012 at 6:40 PM, Rick James <[email protected]>
> 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: [email protected] [mailto:[email protected]] On Behalf Of
> >> Raphael Bauduin
> >> Sent: Tuesday, August 28, 2012 7:12 AM
> >> To: [email protected]
> >> 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
> >>
> >> --
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> >> To unsubscribe: http://lists.mysql.com/mysql
> >
>
>
>
> --
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