Re: index not used?

Scott Marlowe writes:
 > 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.

They're not bigints:

CREATE TABLE table (col int2, row integer, val double precision)

Yes, I vacuumed and analyzed, right after creating the index. Should I try
and issue a few queries beforehand?

--Dan