Mark Cave-Ayland <mark.cave-ayland@xxxxxxxxxxxxxx> writes: > I'm experiencing a strange issue with PostgreSQL 8.3.3 whereby adding > "LIMIT 1" to the query increases the query time from several 10s of ms > to over 5s, and was wondering if anyone with more planner-fu can shed > some light on this. It's hoping that the backwards scan will hit a row with the requested file_id quickly; which might be true on average but isn't true for this particular file_id (nor, presumably, any file_id that hasn't been updated recently). You might consider a two-column index on (file_id, revision_id) to make this type of query fast. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
