On Tue, Jul 10, 2012 at 6:36 PM, Pena Kupen <ku...@wippies.fi> wrote:
> Hi, > > I have searched solution to my problem a few days. On my query, there is > big performance problem. > It seems to me, that problem is on where-part of sql and it's function. > > My sql is: > select count(*) > from table_h where level <= > get_level_value(11268,id,area) and (date1 >= '2011-1-1' > or date2>='2011-1-1') and (date1 <= '2012-07-09' or > date2<='2012-07-09') > This takes about 40sek. > > select count(*) > from table_h where (date1 >= > '2011-1-1' or date2>='2011-1-1') and (date1 <= > '2012-07-09' or date2<='2012-07-09') > when ignoring function, it takes <1sek. > > Function is: > CREATE OR REPLACE FUNCTION get_level_value(_user integer, _id, _area) > RETURNS integer > AS $$ > DECLARE found integer; > BEGIN > SELECT 1 INTO found > FROM table_o > WHERE userid=_user AND > id=_id AND > area=_area; > IF (found) THEN > return 3; > ELSE > return 1; > END IF; > END; > $$ > LANGUAGE plpgsql; > > On explain, it seems to me that this function is on filter and it will > execute on every row. Total resultset contains 1 700 000 rows. > QUERY PLAN > Aggregate (cost=285543.89..285543.90 rows=1 width=0) (actual > time=32391.380..32391.380 rows=1 loops=1) > -> Bitmap Heap Scan on table_h (cost=11017.63..284987.40 rows=222596 > width=0) (actual time=326.946..31857.145 rows=631818 loops=1) > Recheck Cond: ((date1 >= '2011-01-01'::date) OR (date2 >= > '2011-01-01'::date)) > Filter: (((date1 <= '2012-07-09'::date) OR (date2 <= > '2012-07-09'::date)) AND (level <= get_level_value(11268, id, area))) > -> BitmapOr (cost=11017.63..11017.63 rows=669412 width=0) (actual > time=321.635..321.635 rows=0 loops=1) > -> Bitmap Index Scan on date1 (cost=0.00..10626.30 > rows=652457 width=0) (actual time=84.555..84.555 rows=647870 loops=1) > Index Cond: (date1 >= '2011-01-01'::date) > -> Bitmap Index Scan on date2_table_h (cost=0.00..280.03 > rows=16955 width=0) (actual time=237.074..237.074 rows=15222 loops=1) > Index Cond: (date2 >= '2011-01-01'::date) > > How should I handle this situation and use function? > > You could not have good performance using function in case where direct JOIN is only way to have reasonable performance. Stop using function and write join with table_o instead, or put whole query with join inside a function. -- Maxim Boguk Senior Postgresql DBA http://www.postgresql-consulting.ru/ <http://www.postgresql-consulting.com/> Phone RU: +7 910 405 4718 Phone AU: +61 45 218 5678 Skype: maxim.boguk Jabber: maxim.bo...@gmail.com МойКруг: http://mboguk.moikrug.ru/ "People problems are solved with people. If people cannot solve the problem, try technology. People will then wish they'd listened at the first stage."
