From: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz> |
---|---|
To: | Laurent Manchon <lmanchon(at)univ-montp2(dot)fr> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: slow result |
Date: | 2007-01-24 00:51:51 |
Message-ID: | 45B6ADA7.80204@paradise.net.nz |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
Laurent Manchon 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.
Can you post the results of:
analyze verbose tbl;
explain analyze select count(*) from tbl;
The first will give us some info about how many pages tbl has (in 7.4
ISTR it does not state the # of dead rows... but anyway), the second
should help us deduce why it is so slow.
Also as others have pointed out, later versions are quite a bit faster
for sequential scans...
Cheers
Mark
From | Date | Subject | |
---|---|---|---|
Next Message | Mark Kirkwood | 2007-01-24 03:20:47 | Re: extract(field from timestamp) vs date dimension |
Previous Message | Dave Dutcher | 2007-01-23 22:08:47 | Bad Row Count Estimate on View with 8.2 |