Date: Fri, 8 May 2015 20:06:36 +0200
From: Andres Freund <andres@anarazel.de>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@heroku.com>,
 Jeff Janes <jeff.janes@gmail.com>, Stephen Frost <sfrost@snowman.net>,
 Dean Rasheed <dean.a.rasheed@gmail.com>, Bruce Momjian <bruce@momjian.us>,
 Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: INSERT ... ON CONFLICT UPDATE/IGNORE 4.0
Message-ID: <20150508180636.GR12950@alap3.anarazel.de>
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On 2015-05-08 20:37:15 +0300, Heikki Linnakangas wrote:
> Why does INSERT ON CONFLICT pay attention to indcheckxmin? Uniqueness check
> only cares about the most recent committed version of the tuple, and the
> index good for that use immediately. If there was a problem there, the
> uniqueness check in a normal insert have the same problem.

Yea, that's a good angle to view this from.  That'd not be the case, I
think, if we'd allow this to be used on system relations. But since
neither creating an index on system relations, nor using INSERT ON
CONFLICT on them is supported...

Greetings,

Andres Freund


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