On Wed, 5 Apr 2006, Tom Lane wrote:
"Marc G. Fournier" <[EMAIL PROTECTED]> writes:
I'm still searching through Google and whatnot, but not finding anything
off the bat ... is there some way of creating a 'REVERSE INDEX' on a
column in a table?
For instance, when I do a 'CLUSTER' to sort a table based on an INDEX, I'd
like to sort it in reverse order, so would need the INDEX to go from
'GREATEST to LOWEST', vs 'LOWEST to GREATEST' ...
You shouldn't need to worry about that during CLUSTER, as the system is
perfectly capable of scanning an index in either forward or backward
order at runtime. For example,
regression=# explain select * from tenk1 order by unique1;
QUERY PLAN
------------------------------------------------------------------------------------
Index Scan using tenk1_unique1 on tenk1 (cost=0.00..1572.00 rows=10000
width=244)
(1 row)
regression=# explain select * from tenk1 order by unique1 desc;
QUERY PLAN
---------------------------------------------------------------------------------------------
Index Scan Backward using tenk1_unique1 on tenk1 (cost=0.00..1572.00
rows=10000 width=244)
(1 row)
Perfect, that was what I was looking for, thx ...
----
Marc G. Fournier Hub.Org Networking Services (http://www.hub.org)
Email: [EMAIL PROTECTED] Yahoo!: yscrappy ICQ: 7615664
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