| From: | Tobias Brox <tobias(at)nordicbet(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Bruno Wolff III <bruno(at)wolff(dot)to>, Tobias Brox <tobias(at)nordicbet(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Index on a NULL-value |
| Date: | 2005-05-31 05:59:32 |
| Message-ID: | 20050531055932.GL26100@tobias.exoweb.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
> 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
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