Re: index not used?

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