From: Tom Lane <tgl@sss.pgh.pa.us>
To: Claudio Freire <klaussfreire@gmail.com>
cc: Justin Pryzby <pryzby@telsasoft.com>,
        postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: index fragmentation on insert-only table with non-unique column
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Comments: In-reply-to Claudio Freire <klaussfreire@gmail.com>
	message dated "Fri, 03 Jun 2016 23:05:17 -0300"
Date: Sun, 05 Jun 2016 12:03:58 -0400
Message-ID: <969.1465142638@sss.pgh.pa.us>
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Claudio Freire <klaussfreire@gmail.com> writes:
> So correlated index scans look extra favourable vs bitmap index scans
> because bitmap heap scans consider random page costs sans correlation
> effects (even though correlation applies to bitmap heap scans as
> well).

Really?  How?  The index ordering has nothing to do with the order in
which heap tuples will be visited.

			regards, tom lane


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