Re: bitmap scans, btree scans, and tid order

Neil Conway <neilc@samurai.com>

From: Neil Conway <neilc@samurai.com>
To: Jeffrey Baker <jwbaker@acm.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
Date: 2005-05-16T06:35:32Z
Lists: pgsql-hackers
Jeffrey Baker wrote:
> Would you take a patch that retained the optimized executions of plans 
> returning 1 tuple and also fixed the random heap problem?

Can you elaborate on what you're proposing? Obviously sorted b+-tree 
output is important for a lot more than just min()/max(). I don't see an 
obvious way to produce sorted output from a bitmap tree index scan 
without requiring an additional sort step (which would be rather 
pointless -- the whole point of the optimization is to avoid an 
additional sort).

-Neil