On 27 June 2011 07:50, Rob Gansevles <rgansevles@xxxxxxxxx> wrote: > I can confirm, when I call ps.setPrepareThreshold(1) the query is slow > immediately, so the plan must be different with the server prepared > statements. > You can confirm that from psql by doing EXPLAIN ANALYSE SELECT ... ; and then PREPARE ps( ... ) AS SELECT ... ; EXPLAIN ANALYSE EXECUTE ps ( ... ) ; using your query and the parameters in question. It is entirely possible that the plan chosen for the prepared statement will be worse than the one used when the parameters are known at planning time. The prepared statement doesn't know what parameters are going to be used, so it can't always come up with the best plan. See the notes in the PREPARE manual page: http://www.postgresql.org/docs/9.0/static/sql-prepare.html Regards, Dean -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
