Subject: Re: logical decoding / rewrite map vs. maxAllocatedDescs
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Andres Freund <andres@anarazel.de>,
 Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <bc07e92b-d3b9-fabc-2993-edc0ef89be67@2ndquadrant.com>
 <20180813144630.hmzdrbviwao64ube@alvherre.pgsql>
 <20180813144946.fn4zpdwpucx43emz@alap3.anarazel.de>
 <f8221cf4-719c-ac4e-56bf-3be106c41d92@2ndquadrant.com>
 <9552a9ef-250d-c7bf-abca-0c0533215fee@2ndquadrant.com>
Message-ID: <094c73aa-4617-9f21-ee87-8e6ef3850277@2ndquadrant.com>
Date: Tue, 14 Aug 2018 17:26:30 -0400
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On 8/14/18 10:05 AM, Tomas Vondra wrote:
> ...
 >
> I take that back - I can reproduce the crashes, both with and without 
> the patch, all the way back to 9.6. Attached is a bunch of backtraces 
> from various versions. There's a bit of variability depending on which 
> pgbench script gets started first (insert.sql or vacuum.sql) - in one 
> case (when vacuum is started before insert) the crash happens in 
> InitPostgres/RelationCacheInitializePhase3, otherwise it happens in 
> exec_simple_query.
> 
> Another observation is that the failing COPY is not necessary, I can 
> reproduce the crashes without this (so even with wal_level=replica).
>

BTW I have managed to reproduce this on an old test server. If anyone 
wants to take a look, I can arrange ssh access to that machine (for 
trustworthy developers). Let me know.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services