Re: Regex performance issue

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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@xxxxxxxxxxxxx>
To: "Alexandru Coseru" <alexandru.coseru@xxxxxxxxxxxxxxx>
Cc: "Heikki Linnakangas" <heikki@xxxxxxxxxxxxxxxx>; <pgsql-performance@xxxxxxxxxxxxxx>
Sent: Sunday, December 03, 2006 6:05 AM
Subject: Re: [PERFORM] Regex performance issue


"Alexandru Coseru" <alexandru.coseru@xxxxxxxxxxxxxxx> 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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