On Mon, 28 Mar 2005, Stephan Szabo wrote: > > On Mon, 28 Mar 2005, Simon Riggs wrote: > > > run the EXPLAIN after doing > > > SET enable_seqscan = off
... > I think you have to prepare with enable_seqscan=off, because it > effects how the query is planned and prepared. orfs=# SET enable_seqscan = off; SET orfs=# PREPARE test2(int) AS SELECT 1 from measurement where orfs-# id_int_sensor_meas_type = $1 FOR UPDATE; PREPARE orfs=# EXPLAIN ANALYZE EXECUTE TEST2(1); -- non-existent QUERY PLAN ------------------------------------------------------------------------- Index Scan using measurement__id_int_sensor_meas_type_idx on measurement (cost=0.00..883881.49 rows=509478 width=6) (actual time=29.207..29.207 rows=0 loops=1) Index Cond: (id_int_sensor_meas_type = $1) Total runtime: 29.277 ms (3 rows) orfs=# EXPLAIN ANALYZE EXECUTE TEST2(197); -- existing value QUERY PLAN ------------------------------------------------------------------------- Index Scan using measurement__id_int_sensor_meas_type_idx on measurement (cost=0.00..883881.49 rows=509478 width=6) (actual time=12.903..37478.167 rows=509478 loops=1) Index Cond: (id_int_sensor_meas_type = $1) Total runtime: 38113.338 ms (3 rows) -- Karim Nassar Department of Computer Science Box 15600, College of Engineering and Natural Sciences Northern Arizona University, Flagstaff, Arizona 86011 Office: (928) 523-5868 -=- Mobile: (928) 699-9221 ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend