Tobias Brox <[EMAIL PROTECTED]> writes: > [Bruno Wolff III - Mon at 10:36:33PM -0500] > > You want something like this: > > CREATE INDEX b_is_null ON mock(b) WHERE b IS NULL; > > Oh, cool. I wasn't aware that this is possible. This would probably help > us a lot of places. :-)
Yeah it's a cool feature. I'm not 100% sure but I think it still won't consider this index unless the column being indexed is used in some indexable operation. So for example if you had CREATE INDEX b_null on mock(other) WHERE b IS NULL; and something like SELECT * FROM b WHERE b IS NULL ORDER BY other or SELECT * FROM b where other > 0 AND b IS NULL then it would be a candidate because the ORDER BY or the other > 0 make the index look relevant. But I don't think (again I'm not 100% sure) that the partial index WHERE clause is considered in picking which indexes to consider. It *is* considered in evaluating which index is the best one to use and whether it's better than a sequential scan. Just not in the initial choice of which indexes to look at at all. -- greg ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])