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

Re: Query 200x slower on server [PART 2]

From: Richard Huxton <dev(at)archonet(dot)com>
To: NbForYou <nbforyou(at)hotmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Query 200x slower on server [PART 2]
Date: 2006-07-31 09:26:55
Message-ID: 44CDCCDF.8000304@archonet.com (view raw or flat)
Thread:
Lists: pgsql-performance
NbForYou wrote:
> See Query 200x slower on server [PART 1] before reading any further

Cant' find it. Sorry.

> 
> QUERY PLAN ON MY HOME SERVER
[snip]
> Total runtime: 125.432 ms
> 
> This means that the Query is 200 times slower on the webhost!
> 
> How can I resolve this?

First - what is different between the two plans and why? PostgreSQL will 
be choosing a different plan because:
1. It's estimating different numbers of rows for one or more steps
2. It's estimating a different cost for one or more steps
3. It's triggering the genetic optimiser which means you're not 
necessarily going to get the same plan each time.
4. You've got different versions of PG on the different machines.

-- 
   Richard Huxton
   Archonet Ltd

In response to

pgsql-performance by date

Next:From: Axel RauDate: 2006-07-31 10:48:11
Subject: directory tree query with big planner variation
Previous:From: Richard HuxtonDate: 2006-07-31 09:23:31
Subject: Re: How to increase performance?

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