Re: pgbnech: allow to cancel queries during benchmark

On Wed, 6 Sep 2023 20:13:34 +0900
Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp> wrote:

> I attached the updated patch v3. The changes since the previous
> patch includes the following;
>
> I removed the unnecessary condition (&& false) that you
> pointed out in [1].
>
> The test was rewritten by using IPC::Run signal() and integrated
> to "001_pgbench_with_server.pl". This test is skipped on Windows
> because SIGINT causes to terminate the test itself as discussed
> in [2] about query cancellation test in psql.
>
> I added some comments to describe how query cancellation is
> handled as I explained in [1].
>
> Also, I found the previous patch didn't work on Windows so fixed it.
> On non-Windows system, a thread waiting a response of long query can
> be interrupted by SIGINT, but on Windows, threads do not return from
> waiting until queries they are running are cancelled. This is because,
> when the signal is received, the system just creates a new thread to
> execute the callback function specified by setup_cancel_handler, and
> other thread continue to run[3]. Therefore, the queries have to be
> cancelled in the callback function.
>
> [1] https://www.postgresql.org/message-id/a58388ac-5411-4760-ea46-71324d8324cb%40mines-paristech.fr
> [2] https://www.postgresql.org/message-id/20230906004524.2fd6ee049f8a6c6f2690b99c%40sraoss.co.jp
> [3] https://learn.microsoft.com/en-us/windows/console/handlerroutine

I found that --disable-thread-safety option was removed in 68a4b58eca0329.
So, I removed codes involving ENABLE_THREAD_SAFETY from the patch.

Also, I wrote a commit log draft.

Attached is the updated version, v4.

Regards,
Yugo Nagata

--
Yugo NAGATA <nagata(at)sraoss(dot)co(dot)jp>