Scott Marlowe wrote:
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.
I assume not, seen that cost...
Regards
Gaetano Mendola
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