Re: qsort again (was Re: [PERFORM] Strange Create Index

Scott Lamb <slamb@slamb.org>

From: Scott Lamb <slamb@slamb.org>
To: Mark Lewis <mark.lewis@mir3.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, "Craig A. James" <cjames@modgraph-usa.com>, Markus Schaber <schabi@logix-tt.com>, pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org
Date: 2006-02-17T16:18:41Z
Lists: pgsql-hackers, pgsql-performance
On Feb 16, 2006, at 2:17 PM, Mark Lewis wrote:
> Data types which could probably provide a useful function for f  
> would be
> int2, int4, oid, and possibly int8 and text (at least for SQL_ASCII).

...and with some work, floats (I think just the exponent would work,  
if nothing else). bytea. Probably just about anything.

Interesting. If you abandon the idea that collisions should be  
impossible (they're not indexes) or extremely rare (they're not  
hashes), it's pretty easy to come up with a decent hint to avoid a  
lot of dereferences.

--
Scott Lamb <http://www.slamb.org/>