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Re: Assertion failure in pgbench

Tatsuo Ishii <ishii@postgresql.org>

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From: Tatsuo Ishii <ishii@postgresql.org>
To: masao.fujii@gmail.com
Cc: pgsql-hackers@lists.postgresql.org
Date: 2025-08-01T00:03:21Z
Lists: pgsql-hackers 
> On Thu, Jul 31, 2025 at 11:03 AM Tatsuo Ishii <ishii@postgresql.org> wrote:
>> > Yes. When an error occurs and an error response message returned from
>> > backend, pgbench will send one more sync message, then sends ROLLBACK
>> > if necessary. I think the code above should be changed to call
>> > PQgetResult repeatably until it returns NULL.
> 
> I was thinking the same. The attached patch implements that approach,
> and it seems to eliminate the assertion failure.

The patch looks good to me and I confirmed it fixes the the assertion
failure.

>> Correction. That would not be a proper fix. Just removing inner
>> PQgetResult and the Assert is enough?
> 
> Could you explain why you think repeatedly calling PQgetResult
> until it returns NULL isn't the right fix?

Sorry, that was my thinko. I should have had more coffee.
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix assertion failure in pgbench when handling multiple pipeline sync messages.