Re: transction_timestamp() inside of procedures

From: Andres Freund <andres(at)anarazel(dot)de>
To: pgsql-hackers(at)lists(dot)postgresql(dot)org,Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>,Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>,Bruce Momjian <bruce(at)momjian(dot)us>,Michael Paquier <michael(at)paquier(dot)xyz>
Subject: Re: transction_timestamp() inside of procedures
Date: 2018-10-08 17:24:56
Message-ID: E28DF5C1-E2EB-49D6-AC94-AC5FB99E58CF@anarazel.de
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Hi,

On October 8, 2018 10:14:34 AM PDT, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
>> On 02/10/2018 16:58, Andres Freund wrote:
>>> It's a bit weird to make this decision based on these two timestamps
>>> differing. For one, it only indirectly seems to be guaranteed that
>>> xactStartTimestamp is even set to anything here (to 0 by virtue of
>being
>>> a global var).
>
>> Maybe but it seems to be the simplest way without doing major surgery
>to
>> all this code.
>
>This patch doesn't apply over 07ee62ce9. Also, I like the
>timestamp-comparison approach even less than Andres does: I think it's
>probably outright broken, especially since it treats the equality case
>as license to advance xactStartTimestamp.
>
>Surely there is some way that we can directly test whether we're inside
>a
>procedure or not? I think the logic should be basically
>
> if (!IsParallelWorker())
>+ {
>+ if (!InsideProcedure())
> xactStartTimestamp = stmtStartTimestamp;
>+ else
>+ xactStartTimestamp = GetCurrentTimestamp();
>+ }
> else
> Assert(xactStartTimestamp != 0);

Seems more reasonable from here.

Andres
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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