From: Alexandru Coseru <alexandru.coseru@totaltelecom.ro>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: Regex performance issue
Date: Sun, 3 Dec 2006 13:11:29 +0200
Message-ID: <001301c716cb$c8346e80$c7646b56@alex> (raw)
References: <030b01c71651$984577c0$8300a8c0@tridecap.com>
<01ea01c71653$438254e0$3cb16956@alex>
<4571F856.7090808@enterprisedb.com>
<022c01c7165f$17f49e80$3cb16956@alex>
<4571FFA6.6070804@enterprisedb.com>
<024601c71675$81277560$3cb16956@alex>
<12526.1165118712@sss.pgh.pa.us>
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
>
>
>
> --
> No virus found in this incoming message.
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>
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To: pgsql-performance@postgresql.org
Cc: alexandru.coseru@totaltelecom.ro, tgl@sss.pgh.pa.us
Subject: Re: Regex performance issue
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