| From: | Teodor Sigaev <teodor(at)sigaev(dot)ru> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, Reid Thompson <Reid(dot)Thompson(at)ateb(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: If an index is based on 3 columns will a query using |
| Date: | 2005-09-12 15:25:22 |
| Message-ID: | 43259DE2.9010209@sigaev.ru |
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| Lists: | pgsql-general |
> Greg Stark suggests here:
> http://archives.postgresql.org/pgsql-hackers/2005-05/msg00966.php
> that GiST could also be fixed to work with any subset of the index
> columns, but it hasn't been done yet, unless Teodor and Oleg snuck
> something in during that last round of GiST work.
GiST may work with any subset of index columns too. Even in existing code I
don't see any problem except NULL in a first column. GiST doesn't store tuples
with leading NULL value (gist.c lines 174, 326), so index doesn't contained them.
After our work about WAL-lization GiST, it may work with "invalid" tuples
(possibly occured after crash recovery), so itsn't a big deal to add support
NULL in a first column. But freeze date is outdated... Should I add or leave it
to 8.2?
--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/
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