> CREATE INDEX b_is_null ON mock(a) WHERE b IS NULL;
>
> where a is chosen as a column that you frequently also test in
> conjunction with "b IS NULL". That is, the above index can efficiently
> handle queries like
>
> ... WHERE a = 42 AND b IS NULL ...
This is wonderful, it seems like most of our problems (probably also
regarding the "index on timestamp"-thread I started separately) can be
solved with partial indexing on expressions. No need to hide under
bedclothes anymore ;-)
--
Tobias Brox, Beijing