Emil Briggs <emil@xxxxxxxxxxxxxxx> writes: > Does any know why the query behaves like this? Does it have anything to > do with the OR statements in the where clause spanning two different tables? Exactly. > SELECT DISTINCT a.account_id, l.username, a.status, a.company, a.fax_num, > a.primary_phone, a.responsible_first, a.responsible_last FROM > accounts a, logins l, supplemental_info i > WHERE l.account_id=a.account_id and > i.account_id=a.account_id and > ((a.primary_phone = 'xxx-xxx-xxxx') OR (a.alternate_phone = 'xxx-xxx-xxxx') > OR (i.contact_num = 'xxx-xxx-xxxx')) > ORDER BY a.status, a.primary_phone, a.account_id; The system has to fetch all the rows of a, because any of them might join to a row of i matching the i.contact_num condition, and conversely it has to fetch every row of i because any of them might join to a row of a matching one of the phone conditions. It is therefore necessary to effectively form the entire join of a and i; until you've done that there is no way to eliminate any rows. I'm a bit surprised that it's using the indexes at all --- a hash join with seqscan inputs would probably run faster. Try increasing work_mem a bit. regards, tom lane
