Re: Regex performance issue - Mailing list pgsql-performance

From Scott Marlowe
Subject Re: Regex performance issue
Date
Msg-id 1165109498.25316.15.camel@localhost.localdomain
Whole thread Raw
In response to Re: Regex performance issue  ("Alexandru Coseru" <alexandru.coseru@totaltelecom.ro>)
List pgsql-performance
On Sun, 2006-12-03 at 02:53 +0200, Alexandru Coseru wrote:
> Hello..
>
> Thanks for the tip , i think i have got the ideea..
>
> I'm too tired too , and i will try it tommorow.
>
>
> Anyway , anybody has a clue why this regex is that CPU intensive ?  I did
> not saw the light on my drives blinking , and also vmstat doesn't yeld any
> blocks in or out...
> And how can it be optimized ?

I think it's just that you're running the regex across 5400 or so
elements.  at 850 or so milliseconds, that comes out to 150uS for each
comparison.  I'd say it's just the number of comparisons that have to be
made that's killing you here.

pgsql-performance by date:

Previous
From: "Alexandru Coseru"
Date:
Subject: Re: Regex performance issue
Next
From: Tom Lane
Date:
Subject: Re: Regex performance issue