From: Ben <bench@silentmedia.com>
To: pgsql-performance@postgresql.org
Subject: quickly getting the top N rows
Date: Thu, 4 Oct 2007 11:00:30 -0700 (PDT)
Message-ID: <Pine.LNX.4.64.0710041053590.30864@localhost.localdomain> (raw)
If I have this:
create table foo (bar int primary key);
...then in my ideal world, Postgres would be able to use that index on bar
to help me with this:
select bar from foo order by bar desc limit 20;
But in my experience, PG8.2 is doing a full table scan on foo, then
sorting it, then doing the limit. I have a more complex primary key, but I
was hoping the same concept would still apply. Am I doing something wrong,
or just expecting something that doesn't exist?
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To: pgsql-performance@postgresql.org
Cc: bench@silentmedia.com
Subject: Re: quickly getting the top N rows
In-Reply-To: <Pine.LNX.4.64.0710041053590.30864@localhost.localdomain>
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