aditya desai <admad123(at)gmail(dot)com> writes:
> Below query takes 12 seconds. We have an index on postcode.
> select count(*) from table where postcode >= '00420' AND postcode <= '00500'
That query does not match this index:
> CREATE INDEX Table_i1
> ON table USING btree
> ((postcode::numeric));
You could either change postcode to numeric, change all your queries
of this sort to include the cast explicitly, or make an index that
doesn't have a cast.
regards, tom lane