From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>
Subject: Re: heap_abort_speculative() sets xmin to Invalid* without HEAP_XMIN_INVALID
Date: Thu, 23 Jul 2020 17:49:09 -0400
Message-ID: <20200723214909.GA19828@alvherre.pgsql> (raw)
In-Reply-To: <20200723194042.bygzsr6m23pwwkhd@alap3.anarazel.de>
On 2020-Jul-23, Andres Freund wrote:
> I think we should change heap_abort_speculative() to set
> HEAP_XMIN_INVALID in master.
+1
> But we can't really do anything about
> existing tuples without it - therefore we will have to forever take care
> about encountering that combination :(.
>
> Perhaps we should instead or additionally make
> HeapTupleHeaderXminInvalid() explicitly check for InvalidTransactionId?
+1 for doing it as an additional fix, with a fat comment somewhere
explaining where such tuples would come from.
Additionally, but perhaps not very usefully, maybe we could have a
mechanism to inject such tuples so that code can be hardened against the
condition.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: alvherre@2ndquadrant.com, andres@anarazel.de, pg@bowt.ie
Subject: Re: heap_abort_speculative() sets xmin to Invalid* without HEAP_XMIN_INVALID
In-Reply-To: <20200723214909.GA19828@alvherre.pgsql>
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