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(at)sss(dot)pgh(dot)pa(dot)us>
To: "Alexandru Coseru" <alexandru(dot)coseru(at)totaltelecom(dot)ro>
Cc: "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com>;
<pgsql-performance(at)postgresql(dot)org>
Sent: Sunday, December 03, 2006 6:05 AM
Subject: Re: [PERFORM] Regex performance issue

> "Alexandru Coseru" <alexandru(dot)coseru(at)totaltelecom(dot)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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