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

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