pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Steve <cheetah@tanabi.org>
Cc: pgsql-patches@postgreSQL.org, Alvaro Herrera <alvherre@commandprompt.com>
Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)
Date: Sun, 15 Apr 2007 01:11:02 -0400
Message-ID: <26103.1176613862@sss.pgh.pa.us> (raw)
In-Reply-To: <Pine.GSO.4.64.0704141830490.17955@kittyhawk.tanabi.org>
References: <Pine.GSO.4.64.0704121855300.17955@kittyhawk.tanabi.org>
	<10117.1176420763@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704121928440.17955@kittyhawk.tanabi.org>
	<10355.1176422445@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704122001160.17955@kittyhawk.tanabi.org>
	<10503.1176423606@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704122025450.17955@kittyhawk.tanabi.org>
	<12360.1176436194@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704122354430.17955@kit!tyhawk.tanabi.org>
	<26399.1176504501@sss.pgh.pa.us>
	<20070413232409.GI27255@alvh.no-ip.org>
	<7772.1176574886@sss.pgh.pa.us>
	<23414.1176588173@sss.pgh.pa.us>
	<Pine.GSO.4.64.0704141830490.17955@kittyhawk.tanabi.org>

Steve <cheetah@tanabi.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



view thread (10+ messages)  latest in thread

Message-ID: <26103.1176613862@sss.pgh.pa.us>
Permalink:  ../26103.1176613862@sss.pgh.pa.us/
Also on:    postgresql.org/message-id/26103.1176613862@sss.pgh.pa.us

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-performance@postgresql.org
  Cc: tgl@sss.pgh.pa.us, cheetah@tanabi.org, alvherre@commandprompt.com
  Subject: Re: [HACKERS] choose_bitmap_and again (was Re: [PERFORM] Strangely Variable Query Performance)
  In-Reply-To: <26103.1176613862@sss.pgh.pa.us>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox