Re: Potential Join Performance Issue

On Tue, 2008-09-09 at 11:21 -0700, Lawrence, Ramon wrote:

> Our research group has been using the PostgreSQL code base to test new
> join algorithms.

Sounds cool. I'm sure you'll come up with some good things.

You might be interested in this also
http://archives.postgresql.org/pgsql-hackers/2007-01/msg01600.php
after which Greg Stark and I were investigating using
alternate/compressed data structures to avoid the need to switch to
multi-batch hash joins. 

If we knew we were dealing with nearly contiguous ranges of discrete
values, we could store the missing values rather than the present values
using an HRL encoded bitmap. Other ideas are possible also, I'm sure.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support