Re: 8.1 (win32): partial index not used?
От | |
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Тема | Re: 8.1 (win32): partial index not used? |
Дата | |
Msg-id | 12c401c66a65$03a194c0$6402a8c0@iwing обсуждение исходный текст |
Ответ на | 8.1 (win32): partial index not used? (<me@alternize.com>) |
Список | pgsql-novice |
> i've noticed a problem with an index, where the index wouldn't be used > anymore as soon as a partial condition is added. please ignore my partial index problem. of course i would have to define the partial index part correctly: it works just fine this way: movies_folder_idx: USING btree ((lower((mov_folder)::text))) WHERE (lower((mov_folder)::text) <> ''::text); still, 0.2ms for querying an index containing ~3000 entries seems quite long: SELECT * FROM oldtables.movies WHERE lower(mov_folder) = 'harrypotter5' AND mov_year = 2007 LIMIT 1 Limit (cost=5.67..9.68 rows=1 width=232) (actual time=0.084..0.084 rows=1 loops=1) -> Bitmap Heap Scan on movies (cost=5.67..9.68 rows=1 width=232) (actual time=0.081..0.081 rows=1 loops=1) Recheck Cond: ((lower((mov_folder)::text) = 'harrypotter5'::text) AND (mov_year = 2007)) -> BitmapAnd (cost=5.67..5.67 rows=1 width=0) (actual time=0.075..0.075 rows=0 loops=1) -> Bitmap Index Scan on movies_folder_idx (cost=0.00..2.64 rows=182 width=0) (actual time=0.034..0.034 rows=1 loops=1) Index Cond: (lower((mov_folder)::text) = 'harrypotter5'::text) -> Bitmap Index Scan on movies_mov_year_idx (cost=0.00..2.78 rows=222 width=0) (actual time=0.036..0.036 rows=62 loops=1) Index Cond: (mov_year = 2007) Total runtime: 0.217 ms any tipps? - thomas
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