On Tue, Oct 19, 2004 at 07:38:49PM -0300, Alvaro Herrera wrote:
> Huh, you are wrong. At least btree does index null values, and one
> other index method does too. The other two index methods don't. What
> doesn't work is using an index with the IS NULL construct, because it's
> not an operator. Maybe that can be fixed by some other means ... some
> parser magic perhaps.
Wow, that's news to me, and important to remember! Where is it
documented? I don't see it in the index chapter...
I think it would be very helpful to have a chapter that gives
information like this for experienced DBAs who are trying to learn
PostgreSQL and don't want to read through all the documentation but need
to know important differences in how PostgreSQL works that would be easy
to miss. Not indexing NULLs (ala Oracle), or not using an index for IS
NULL would certainly be examples. Things listed at
http://sql-info.de/postgresql/postgres-gotchas.html would also be likely
candidates.
--
Jim C. Nasby, Database Consultant decibel@decibel.org
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