Re: Old row version in hot chain become visible after a freeze

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
Cc: Peter Geoghegan <pg(at)bowt(dot)ie>, "Wood, Dan" <hexpert(at)amazon(dot)com>, "pgsql-bugs(at)postgresql(dot)org" <pgsql-bugs(at)postgresql(dot)org>, Andres Freund <andres(at)anarazel(dot)de>
Subject: Re: Old row version in hot chain become visible after a freeze
Date: 2017-09-06 13:27:38
Message-ID: 20170906132738.2dpwvnfcuevjofhl@alvherre.pgsql
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Another thing is that if you're going through heap_copy_data, the tuple
is only checked for DEAD, not RECENTLY_DEAD. Maybe there is no bug here
but I'm not sure yet.

I attach the patch as I have it now -- mostly comment tweaks, but also
the change to not mark page as all-frozen when we skip freezing a
recently read tuple. I also renamed the test case, because I think it
may be possible to reach the problem code without involving a multixact.
Haven't tried too hard though.

Álvaro Herrera
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Attachment Content-Type Size
0001-test-cases.patch text/plain 5.5 KB
0002-Don-t-freeze-recently-dead-HOT-tuples.patch text/plain 5.2 KB

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