Dnia 2003-12-22 11:39, Użytkownik Ryszard Lach napisał:
> Hi.
>
> I have a table with 24k records and btree index on column 'id'. Is this
> normal, that 'select max(id)' or 'select count(id)' causes a sequential
> scan? It takes over 24 seconds (on a pretty fast machine):
'select count(id)'
Yes, this is normal. Because of MVCC all rows must be checked and
Postgres doesn't cache count(*) like Mysql.
'select max(id)'
This is also normal, but try to change this query into:
select id from some_table order by id desc limit 1;
What is your Postgresql version?
Regards,
Tomasz Myrta