Robert James <srobertjames@xxxxxxxxx> wrote: > If I have a slow_function(), and I create an index of > slow_function(field), will Postgres use that index to avoid having to > recompute the function? > > Example: > > SELECT slow_function(field1) FROM table1 WHERE id = 5 > > It won't use the index on field1 to _find_ the record. Can it use it > to compute the field? If you're not going to search on the function results you are probably better off adding it to the table itself and maintaining it on BEFORE INSERT and BEFORE UPDATE triggers. You could play around with trying to put it just in an index with other columns and hoping for an index-only scan, but that is probably not a great way to go. -- Kevin Grittner EDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
