Skip site navigation (1) Skip section navigation (2)

Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Steve <cheetah(at)tanabi(dot)org>
Cc: pgsql-patches(at)postgreSQL(dot)org, Alvaro Herrera <alvherre(at)commandprompt(dot)com>
Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)
Date: 2007-04-15 05:11:02
Message-ID: 26103.1176613862@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-patchespgsql-performance
Steve <cheetah(at)tanabi(dot)org> writes:
>> Steve, can you try this out on your queries and see if it makes better
>> or worse decisions?  It seems to fix your initial complaint but I do
>> not have a large stock of test cases to try.

>  	Wow, this is a remarkable difference.  Queries that were taking 
> minutes to complete are coming up in seconds.  Good work, I think this'll 
> solve my customer's needs for their demo on the 19th :)

Can you find any cases where it makes a worse choice than before?
Another thing to pay attention to is whether the planning time gets
noticeably worse.  If we can't find any cases where it loses badly
on those measures, I'll feel comfortable in applying it...

			regards, tom lane

In response to

Responses

pgsql-performance by date

Next:From: Tom LaneDate: 2007-04-15 05:29:01
Subject: Re: FK triggers misused?
Previous:From: SteveDate: 2007-04-14 22:55:45
Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)

pgsql-hackers by date

Next:From: Lukas Kahwe SmithDate: 2007-04-15 08:06:03
Subject: Wishlist updates
Previous:From: Tom LaneDate: 2007-04-15 05:01:16
Subject: Re: Server-side support of all encodings

pgsql-patches by date

Next:From: SteveDate: 2007-04-15 08:13:53
Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)
Previous:From: SteveDate: 2007-04-14 22:55:45
Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group