Re: getting an index to work with partial indices ...

"Marc G. Fournier" <scrappy@postgresql.org> writes:
> But, ti will if I try 'priority = -2' ... what is teh threshhold for using
> the index?  obviously 10% of the records is too high ...

Depends on a lot of factors, but usually somewhere between 1% and 10%.
(The new bitmap index scan code in 8.1 should be workable for higher
percentages.)  If this doesn't seem to square with reality for you,
you might try reducing random_page_cost.

            regards, tom lane