From: Alvaro Herrera <alvaro.herrera@2ndquadrant.com>
To: Boris Kolpackov <boris@codesynthesis.com>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Pipeline mode and PQpipelineSync()
Date: Tue, 29 Jun 2021 09:54:49 -0400
Message-ID: <202106291354.wyn7ar6emdm6@alvherre.pgsql> (raw)
In-Reply-To: <boris.20210624103805@codesynthesis.com>
On 2021-Jun-24, Boris Kolpackov wrote:
> I've hit another similar case except now an unexpected NULL result is
> returned in the middle of PGRES_PIPELINE_ABORTED result sequence. The
> call sequence is as follows:
>
> PQsendQueryPrepared() # INSERT #1
> PQflush()
> PQsendQueryPrepared() # INSERT #2
> PQflush()
> ...
> PQsendQueryPrepared() # INSERT #251 -- insert duplicate PK
> PQflush()
> ...
> PQsendQueryPrepared() # INSERT #343
> PQflush()
> PQconsumeInput() # At this point select() indicates we can read.
> PQgetResult() # NULL -- unexpected but skipped (see prev. email)
> PQgetResult() # INSERT #1
> PQgetResult() # NULL
> PQgetResult() # INSERT #2
> PQgetResult() # NULL
> ...
> PQgetResult() # INSERT #251 error result, SQLSTATE 23505
> PQgetResult() # NULL
> PQgetResult() # INSERT #252 PGRES_PIPELINE_ABORTED
> PQgetResult() # NULL
> PQgetResult() # INSERT #253 PGRES_PIPELINE_ABORTED
> PQgetResult() # NULL
> ...
> PQgetResult() # INSERT #343 NULL (???)
>
> Notice that result #343 corresponds to the last PQsendQueryPrepared()
> call made before the socket became readable (it's not always 343 but
> around there).
No luck reproducing any problems with this sequence as yet.
--
Álvaro Herrera 39°49'30"S 73°17'W
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To: pgsql-hackers@postgresql.org
Cc: alvaro.herrera@2ndquadrant.com, boris@codesynthesis.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Pipeline mode and PQpipelineSync()
In-Reply-To: <202106291354.wyn7ar6emdm6@alvherre.pgsql>
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