Re: Regex performance issue

Hello..

I presumed CPU intensive  because:
    1) I have no hdd lights turn on during a series of queries (about 50 of
them)
    2) vmstat doesn't give me blocks in and just a couple of blocks out.
    3) top  reports between 95 and 100 user cpu    .    sometimes ,i can see
some  hi and si work  (max of 2%).


I'm pretty sure that the whole table is in cache..
The table size is about 50 Megs  , and I have 1 Gb of RAM..
I have no other RAM eating procesess.

Could it be related to  CPU <-> RAM speed ?

Regards
    Alex

----- Original Message -----
From: "Tom Lane" <tgl@sss.pgh.pa.us>
To: "Alexandru Coseru" <alexandru.coseru@totaltelecom.ro>
Cc: "Heikki Linnakangas" <heikki@enterprisedb.com>;
<pgsql-performance@postgresql.org>
Sent: Sunday, December 03, 2006 6:05 AM
Subject: Re: [PERFORM] Regex performance issue


> "Alexandru Coseru" <alexandru.coseru@totaltelecom.ro> writes:
>> Anyway , anybody has a clue why this regex is that CPU intensive ?
>
> The EXPLAIN result you posted offers *no* evidence that the regexp is
> CPU intensive.  All you know is that it took 850+ msec to fetch 5200
> rows from disk and apply the regexp filter to them.  There's no evidence
> here that that was CPU time and not I/O time.
>
> regards, tom lane
>
>
>
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