From: Teodor Sigaev <teodor@sigaev.ru>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Jim Nasby <Jim.Nasby@bluetreble.com>
Cc: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: [PROPOSAL] Covering + unique indexes.
Date: Mon, 14 Sep 2015 21:57:53 +0300
Message-ID: <55F718B1.8030306@sigaev.ru> (raw)
In-Reply-To: <CAEepm=2G4jdaoXHU0PJ7MqLms88==r44z9bvLpnzjyOTDzwAEw@mail.gmail.com>
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> It surprised me that you can INCLUDE extra columns on non-UNIQUE
> indexes, since you could just add them as regular indexed columns for
> the same effect. It looks like when you do that in SQL Server, the
> extra columns are only stored on btree leaf pages and so can't be used
> for searching or ordering. I don't know how useful that is or if we
> would ever want it... but I just wanted to note that difference, and
Agree
> that the proposed UNIQUE ON FIRST n COLUMNS syntax and catalog change
> can't express that.
Proposal suggests to work only with unique index by exactly your
reasons above.
--
Teodor Sigaev E-mail: teodor@sigaev.ru
WWW: http://www.sigaev.ru/
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Cc: teodor@sigaev.ru, thomas.munro@enterprisedb.com, Jim.Nasby@bluetreble.com, a.lubennikova@postgrespro.ru
Subject: Re: [PROPOSAL] Covering + unique indexes.
In-Reply-To: <55F718B1.8030306@sigaev.ru>
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