| Hi, I upgraded to 8.2.4 but there was no significant change in performance. I did notice that hte query appears to be executed incorrectly. Specifically, it appears to perform each equality operation then perform a bitwise AND. I think it should instead be performing one of the equalities then use the results to perform the other. This would create a vastly smaller dataset for the second to work with. I have pasted the EXPLAIN ANALYZE below to illustrate: =# explain analyze select s_content,textdir from (SELECT * from text_search WHERE tb_id='P2_TB00001') AS a where path_id='4'; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------- Bitmap Heap Scan on text_search (cost=39864.98..59746.59 rows=5083 width=36) (actual time=7418.651..7418.863 rows=52 loops=1) Recheck Cond: ((path_id = 4) AND (tb_id = 'P2_TB00001'::text)) -> BitmapAnd (cost=39864.98..39864.98 rows=5083 width=0) (actual time=6706.928..6706.928 rows=0 loops=1) -> Bitmap Index Scan on idx_search_path_id (cost=0.00..16546.34 rows=1016571 width=0) (actual time=6609.458..6609.458 rows=52777 loops=1) Index Cond: (path_id = 4) -> Bitmap Index Scan on idx_search_tb_id (cost=0.00..23315.85 rows=1016571 width=0) (actual time=96.903..96.903 rows=411341 loops=1) Index Cond: (tb_id = 'P2_TB00001'::text) Total runtime: 7419.128 ms (8 rows) Is there are way to force the "Bitmap Index Scan on idx_search_tb_id" to perform first then let "Bitmap Index Scan on idx_search_path_id" use the results? Benjamin On Apr 23, 2007, at 5:12 PM, Tom Lane wrote:
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