Re: Configuration Advice

Stephen Conley <cheetah@tanabi.org>

From: Steve <cheetah@tanabi.org>
To: Bruno Wolff III <bruno@wolff.to>
Cc: Adam Rich <adam.r@sbcglobal.net>, pgsql-performance@postgresql.org
Date: 2007-01-17T23:58:52Z
Lists: pgsql-performance
> Note that you only need to have the ASC and DESC versions of opclasses when
> you are going to use multicolumn indexes with some columns in ASC order and
> some in DESC order. For columns used by themselves in an index, you don't
> need to do this, no matter which order you are sorting on.
>

Yeah, I assumed the people 'in the know' on this kind of stuff would know 
the details of why I have to have those, and therefore I wouldn't have to 
go into detail as to why -- but you put your finger right on it. :) 
Unfortunately the customer this is for wants certain columns joined at the 
hip for querying and sorting, and this method was a performance godsend 
when we implemented it (with a C .so library, not using SQL in our 
opclasses or anything like that).


Steve