Even with only 16 Mo, your query cache is quite efficient (78% of your
queries are fetched directly from the cache).
Try to increaze your query_cache_size until there's no more additional
lowmem_prunes reported.
And executed from time to time FLUSH QUERY CACHE to defragment your
query cache.
Jocelyn
Mauricio Pellegrini a écrit :
> Thanks these are fresh results
>
> | query_cache_limit | 1048576 |
> | query_cache_min_res_unit | 4096 |
>
>
> show status like "ques%";
> +---------------+----------+
> | Variable_name | Value |
> +---------------+----------+
> | Questions | 14189604 |
> +---------------+----------+
>
>
> show status like "qcache%";
> +-------------------------+----------+
> | Variable_name | Value |
> +-------------------------+----------+
> | Qcache_free_blocks | 2731 |
> | Qcache_free_memory | 12372064 |
> | Qcache_hits | 11156553 |
> | Qcache_inserts | 1945643 |
> | Qcache_lowmem_prunes | 372898 |
> | Qcache_not_cached | 509594 |
> | Qcache_queries_in_cache | 4101 |
> | Qcache_total_blocks | 11000 |
> +-------------------------+----------+
>
>
> On Wed, 2005-03-09 at 20:19, Jocelyn Fournier wrote:
>
>>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
>>>
>>>
>>>
>
>
