From: | "Alexandru Coseru" <alexandru(dot)coseru(at)totaltelecom(dot)ro> |
---|---|
To: | "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Regex performance issue |
Date: | 2006-12-03 11:11:29 |
Message-ID: | 001301c716cb$c8346e80$c7646b56@alex |
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Thread: | |
Lists: | pgsql-performance |
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
>
>
>
> --
> No virus found in this incoming message.
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>
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