Chris Angelico <rosuav@xxxxxxxxx> writes: > I have a table with a timestamptz column for the "effective date/time" > of the row, and need to have some queries that look only for those > entries for which that is in the future or VERY recently - which will > be a small minority of rows. I'm looking at something like: > CREATE INDEX on tablename (effective) where effective>timestamptz > 'now'-interval '21 days' I think this falls under the rubric of "premature optimization is the root of all evil". Just use a plain index on the timestamptz column and be happy. Searches that only look at the extremal values of a column work perfectly well with a full index, because they only need to examine a small range of the index. > Is there a way around this? Also, how would I go about pruning the > index, preferably in such a way that the old index can be used? And that is exactly the reason why a partial index of this sort isn't a win --- you'd be expending many extra cycles to keep it trimmed. 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
