The following bug has been logged on the website: Bug reference: 6658 Logged by: Maxim Boguk Email address: maxim.bo...@gmail.com PostgreSQL version: 9.1.3 Operating system: Linux Description:
Hi, I have 2 queries which have the same plan/same performance on 8.3 but on 9.1.3 fist one doesn't perform well because condition doesn't pushed down to subquery: --slow on 9.1.3 but fast on 8.3.13 --helper just shell view db=# explain (analyze,verbose) select id from (SELECT id, regexp_replace(btrim(((((((COALESCE(NULLIF(start_number, 0) || ' '::text, ''::text) || address) || ' '::text) || suburb) || ' '::text) || state) || ' '::text) || postcode), ' +'::text, ' '::text, 'g'::text) AS search_string FROM helper WHERE start_number IS NOT NULL AND start_alpha IS NOT NULL AND end_number IS NULL ) AS _t WHERE search_string='something'; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Subquery Scan on _t (cost=7715.15..2141451.98 rows=55630 width=4) (actual time=4132.959..4132.959 rows=0 loops=1) Output: _t.id Filter: (_t.search_string = 'something'::text) -> Bitmap Heap Scan on data_table (cost=7715.15..1557337.03 rows=11125999 width=45) (actual time=92.290..4066.518 rows=403344 loops=1) Output: id, regexp_replace(btrim((((((((COALESCE(((NULLIF(start_number, 0))::text || ' '::text), ''::text) || upper(regexp_replace(btrim(((COALESCE((name || ' '::text), ''::text) || COALESCE((extension || ' '::text), ''::text)) || COALESCE(direction, ''::text))), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(locality_name, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(state_code, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(post_code, ''::text)), ' +'::text, ' '::text, 'g'::text)))), ' +'::text, ' '::text, 'g'::text) Recheck Cond: ((start_number IS NOT NULL) AND (upper((start_alpha)::text) IS NOT NULL) AND (end_number IS NULL)) -> Bitmap Index Scan on ix_search_full5 (cost=0.00..4933.65 rows=11125999 width=0) (actual time=59.118..59.118 rows=403344 loops=1) Total runtime: 4133.001 ms (8 rows) --fast on both 9.1.3 and 8.3.13 --flat version (search_string condition manually inlined) db=# explain (analyze, verbose) SELECT id FROM helper WHERE start_number IS NOT NULL AND start_alpha IS NOT NULL AND end_number IS NULL AND regexp_replace(btrim(((((((COALESCE(NULLIF(start_number, 0) || ' '::text, ''::text) || address) || ' '::text) || suburb) || ' '::text) || state) || ' '::text) || postcode), ' +'::text, ' '::text, 'g'::text) = 'something'; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Index Scan using ix_search_full5 on data_table (cost=0.07..55842.16 rows=55630 width=4) (actual time=0.006..0.006 rows=0 loops=1) Output: id Index Cond: (regexp_replace(btrim((((((((COALESCE(((NULLIF(start_number, 0))::text || ' '::text), ''::text) || upper(regexp_replace(btrim(((COALESCE((name || ' '::text), ''::text) || COALESCE((extension || ' '::text), ''::text)) || COALESCE(direction, ''::text))), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(locality_name, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(state_code, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(post_code, ''::text)), ' +'::text, ' '::text, 'g'::text)))), ' +'::text, ' '::text, 'g'::text) = 'something'::text) Total runtime: 0.027 ms (4 rows) db=# \d+ ix_search_full5 Index "ix_search_full_address5" Column | Type | Definition | Storage | Description ----------------+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------+------------- regexp_replace | text | regexp_replace(btrim(((((((COALESCE(NULLIF(start_number, 0) || ' '::text, ''::text) || upper(regexp_replace(btrim((COALESCE(name || ' '::text, ''::text) || COALESCE(extension || ' '::text, ''::text)) || COALESCE(direction, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(locality_name, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(state_code, ''::text)), ' +'::text, ' '::text, 'g'::text))) || ' '::text) || upper(regexp_replace(btrim(COALESCE(post_code, ''::text)), ' +'::text, ' '::text, 'g'::text))), ' +'::text, ' '::text, 'g'::text) | extended | btree, for table "address", predicate (start_number IS NOT NULL AND upper(start_alpha::text) IS NOT NULL AND end_number IS NULL) All *_cost parameters default on both databases, no amout play with *_cost setting on 9.1.3 helps. No changes with other settings on 9.1.3 help. I can't yet create selfcontained test case but I working on in. It's visible that planner see fast way is really faster/cheaper, however something prevent planner from flatten subquery. Kind Regards, Maksym -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs