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From:Jocelyn Fournier Date:March 9 2005 11:19pm
Subject:Re: Query_cache_size Question
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Hi,

How many questions for thoses results ?
There's a lot of lowmem_prunes, so I would indeed increase the memory 
size to reduce the risk of lowmem_prunes.
What is your query_cache_limit ?

   Jocelyn

Mauricio Pellegrini a écrit :
> Thanks,  this the result of show status like "qcache%"
> 
> +-------------------------+----------+
> | Variable_name           | Value    |
> +-------------------------+----------+
> | Qcache_free_blocks      | 3330     |
> | Qcache_free_memory      | 13372320 |
> | Qcache_hits             | 11119149 |
> | Qcache_inserts          | 1942009  |
> | Qcache_lowmem_prunes    | 372898   |
> | Qcache_not_cached       | 508528   |
> | Qcache_queries_in_cache | 3160     |
> | Qcache_total_blocks     | 9711     |
> +-------------------------+----------+
> 
> Am I right at saying that the value (16Mb)is ok ?
> 
> Qcache_not_cached means the number of query results that didn't get into
> the cache because of a space limitation ? 
> If so, perhaps adding few more Mb would improve that number , isn't it?
> 
> 
> 
> 
> On Wed, 2005-03-09 at 19:30, Dan Nelson wrote:
> 
>>In the last episode (Mar 09), Mauricio Pellegrini said:
>>
>>>Hi, I'm trying to tweak the execution time for querys on my mysql
>>>server which is using InnoDB.
>>>
>>>I know that there are a lot of things to check but one of them,
>>>perhaps not the most important, is the query_cache_size.
>>>
>>>I have a dual Xeon cpu with 4gb of ram and this is a Linux dedicated
>>>server which runs only Apache and Mysql 4.1.5
>>>
>>>I've declared Query_cache_size = 16M in the my.cnf file and I would
>>>say that in the whole we have 60% of select querys and a 40% of
>>>update querys.
>>>
>>>Is Query_cache_size=16M too conservative considering that I have 4Gb
>>>of ram ?
>>
>>A better question is: what is your current utilization of that 16MB
>>cache?  The query cache flushes any results dependant on a table when
>>that table is modified, so if you really have 40% updates, chances are
>>that very few queries are cachable at all.  Run
>>
>>  show status like 'qcache%';
>>
>>, and take a look at free_memory, inserts, and hits.
>> 
>>-- 
>>	Dan Nelson
>>	dnelson@stripped
> 
> 
> 
Thread
Query_cache_size QuestionMauricio Pellegrini9 Mar
  • Re: Query_cache_size QuestionDan Nelson9 Mar
    • Re: Query_cache_size QuestionMauricio Pellegrini9 Mar
      • Re: Query_cache_size QuestionJocelyn Fournier10 Mar
        • Re: Query_cache_size QuestionMauricio Pellegrini10 Mar
          • Re: Query_cache_size QuestionJocelyn Fournier10 Mar
      • Re: Query_cache_size QuestionDan Nelson10 Mar
RE: Query_cache_size QuestionKostas Pyliouras9 Mar