Re: Performant queries on table with many boolean columns
От | Teodor Sigaev |
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Тема | Re: Performant queries on table with many boolean columns |
Дата | |
Msg-id | 5718A59D.4090706@sigaev.ru обсуждение исходный текст |
Ответ на | Re: Performant queries on table with many boolean columns ("David G. Johnston" <david.g.johnston@gmail.com>) |
Ответы |
Re: Performant queries on table with many boolean columns
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Список | pgsql-performance |
> looks like a deal for contrib/bloom index in upcoming 9.6 release > Curious, it doesn't look like it will work with booleans out of the box. > http://www.postgresql.org/docs/devel/static/bloom.html There is no rocket science here: # create table x (v bool); # create index i on x using bloom ((v::int4)); # set enable_seqscan=off; --because of empty table # explain select * from x where v::int4 = 1; QUERY PLAN ------------------------------------------------------------------ Bitmap Heap Scan on x (cost=25.08..35.67 rows=14 width=1) Recheck Cond: ((v)::integer = 1) -> Bitmap Index Scan on i (cost=0.00..25.07 rows=14 width=0) Index Cond: ((v)::integer = 1) Or cast it to "char" type (with quoting!) -- Teodor Sigaev E-mail: teodor@sigaev.ru WWW: http://www.sigaev.ru/
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