[TYPO3-dev] indexed_search kills server

[Steffen Kamper]

"Ernesto Baschny [cron IT]" <ernst at cron-it.de> schrieb im Newsbeitrag 
news:mailman.1.1211364311.13646.typo3-dev at lists.netfielders.de...
> Steffen Kamper wrote: on 21.05.2008 11:26:
>
>> on my server i encountered massive problems with indexed_search.
>>
>> Have a look to query times:
>>
>> # Time: 080521 10:18:31
>> # User at Host: web2[web2] @ localhost []
>> # Query_time: 555  Lock_time: 0  Rows_sent: 30  Rows_examined: 21263272
>> SELECT IR.phash
>>                         FROM index_words IW,
>>                                                 index_rel IR,
>>                                                 index_section ISEC
>>                         WHERE
>>                                 IW.baseword LIKE '%einrichtung%'
>>                                                 AND IW.wid=IR.wid
>>                                                 AND ISEC.phash = IR.phash
>>                                                 AND ISEC.rl0 IN (1)
>>                                                  AND is_stopword=0
>>                         GROUP BY IR.phash;
>
> Even for this amount of rows it seems mysql is taking a bit "too much" 
> time. I guess that your server is not well tuned for the Apache + MySQL 
> configuration.
>
> In one particular installation I have about 6 million entries in the 
> index_rel table (where you have 21 million) and the same query returns in 
> about 0.21 secs, and this is being hosted on a virtual environment (xen 
> based).
>
> So I guess your 555 secs are caused by memory exhaustion, server having to 
> swap and the whole I/O performance going down to the ground. Consider 
> tuning the mysql + apache combination to not go much over the amount of 
> available RAM (by limiting max_connections and MaxClients) and tweak MySQL 
> to make better use of the RAM. Also make sure you have fast HDD-access, 
> make use of NCQ (if possible), etc.
>
> Cheers,
> Ernesto

Thanks for your suggestions. I forwarded this to my sysadmin and he will 
check your proposals.

vg Steffen