From: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
---|---|
To: | Scott Marlowe <smarlowe(at)g2switchworks(dot)com> |
Cc: | andremachado <andremachado(at)techforce(dot)com(dot)br>, pgsql-performance(at)postgresql(dot)org |
Subject: | Re: firebird X postgresql 8.1.2 windows, performance |
Date: | 2006-03-07 17:22:24 |
Message-ID: | 20060307172224.GG6748@surnet.cl |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
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.
From | Date | Subject | |
---|---|---|---|
Next Message | PFC | 2006-03-07 18:09:15 | Re: Planner enhancement suggestion. |
Previous Message | Scott Marlowe | 2006-03-07 17:18:59 | Re: firebird X postgresql 8.1.2 windows, performance |