From: Alvaro Herrera <alvherre@commandprompt.com>
To: Scott Marlowe <smarlowe@g2switchworks.com>
Cc: andremachado <andremachado@techforce.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: firebird X postgresql 8.1.2 windows, performance
Date: Tue, 7 Mar 2006 14:22:24 -0300
Message-ID: <20060307172224.GG6748@surnet.cl> (raw)
In-Reply-To: <1141751939.18820.174.camel@state.g2switchworks.com>
References: <20060307162842.M37264@techforce.com.br>
<1141751333.18820.172.camel@state.g2switchworks.com>
<20060307171514.GE6748@surnet.cl>
<1141751939.18820.174.camel@state.g2switchworks.com>
Scott Marlowe wrote:
> On Tue, 2006-03-07 at 11:15, Alvaro Herrera wrote:
> > Scott Marlowe wrote:
> >
> > > Lastly, I noticed that after you clusters on all your indexes, the query
> > > planner switched from a merge join to a hash join, and it was slower.
> > > You might wanna try turning off hash joins for a quick test to see if
> > > merge joins are any faster.
> >
> > Anyway please note that clustering "all indexes" does not really make
> > sense. You can cluster only on one index. If you cluster on another,
> > then the first clustering will be lost. Better make sure to cluster on
> > the one index where it makes the most difference.
>
> Note that I was referring to his clustering on an index for each table.
> I.e. not on every single index. but he clustered on four tables /
> indexes at once, so that was what I was referring to. Sorry for any
> confusion there.
Ah, sorry, I misinterpreted.
> So, do you see any obvious, low hanging fruit here?
Sorry, I didn't look at his test case very closely :-(
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
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: alvherre@commandprompt.com, smarlowe@g2switchworks.com, andremachado@techforce.com.br
Subject: Re: firebird X postgresql 8.1.2 windows, performance
In-Reply-To: <20060307172224.GG6748@surnet.cl>
* 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