Re: slow result - Mailing list pgsql-performance

From Bruno Wolff III
Subject Re: slow result
Date
Msg-id 20070123175951.GC20870@wolff.to
Whole thread Raw
In response to slow result  (Laurent Manchon <lmanchon@univ-montp2.fr>)
Responses Re: slow result
List pgsql-performance
On Tue, Jan 23, 2007 at 11:34:52 +0100,
  Laurent Manchon <lmanchon@univ-montp2.fr> wrote:
> Hi,
>
> I have a slow response of my PostgreSQL database 7.4 using this query below
> on a table with 800000 rows:
>
> select count(*)from tbl;
>
> PostgreSQL return result in 28 sec every time.
> although MS-SQL return result in 0.02 sec every time.

Besides the other advice mentioned in this thread, check that you don't
have a lot of dead tuples in that table. 28 seconds seems a bit high
for even a sequential scan of 800000 tuples unless they are pretty large.

pgsql-performance by date:

Previous
From: "Merlin Moncure"
Date:
Subject: Re: extract(field from timestamp) vs date dimension
Next
From: "Dave Dutcher"
Date:
Subject: Bad Row Count Estimate on View with 8.2