[postgis-users] OT Understanding slow queries

[fork]

Charles Galpin <cgalpin <at> lhsw.com> writes:

> explain select count(l.*) 
> from links l, source_link ld where l.link_id = ld.link_id;

Can you try this returning some sort of value (like the keys) instead of a
count(*)?  count(*) can be pretty slow in Postgres, sometimes 
(I think) forcinga seq scan.

I am not particularly confident this will fix your problem, 
but it is worth a shot.

I would also experiment with DISTINCT and LIMIT, after
 making sure ANALYZE has been run appropriately.