Re: Select max(foo) and select count(*) optimization
Neil Conway <neilc@samurai.com>
From: Neil Conway <neilc@samurai.com>
To: siracusa@mindspring.com
Cc: Postgres Performance <pgsql-performance@postgresql.org>
Date: 2004-01-05T20:23:16Z
Lists: pgsql-performance
John Siracusa <siracusa@mindspring.com> writes: > 1. The query "select max(foo) from bar" where the column foo has an index. > Aren't indexes ordered? If not, an "ordered index" would be useful in this > situation so that this query, rather than doing a sequential scan of the > whole table, would just "ask the index" for the max value and return nearly > instantly. http://www.postgresql.org/docs/current/static/functions-aggregate.html -Neil