Re: index not used?
От | Scott Marlowe |
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Тема | Re: index not used? |
Дата | |
Msg-id | 1098287046.21035.45.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | index not used? (Dan Pelleg <daniel+pgsql@pelleg.org>) |
Ответы |
Re: index not used?
Re: index not used? |
Список | pgsql-general |
On Wed, 2004-10-20 at 08:06, Dan Pelleg wrote: > I'm trying to access a table with about 120M rows. It's a vertical version > of a table with 360 or so columns. The new columns are: original item col, > original item row, and the value. > > I created an index: > > CREATE INDEX idx on table (col, row) > > however, selects are still very slow. It seems it still needs a sequential > scan: > > EXPLAIN SELECT * FROM table WHERE col=1 AND row=10; > QUERY PLAN > ------------------------------------------------------------------------------ > Seq Scan on table (cost=100000000.00..102612533.00 rows=1 width=14) > Filter: ((col = 1) AND ("row" = 10)) > > What am I doing wrong? What type are row and col? If they're bigint (i.e. not int / int4) then you might need to quote the value to get the query to use an index: SELECT * FROM table WHERE col='1' AND row='10'; also, have you vacuumed / analyzed the table? I'm assuming yes.
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