Horton

Re: Add non-blocking version of PQcancel

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Jelte Fennema <Jelte.Fennema@microsoft.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2022-01-13T00:44:11Z
Lists: pgsql-hackers 
Hi,

On 2022-01-12 15:22:18 +0000, Jelte Fennema wrote:
> This patch also includes a test for this new API (and also the already
> existing cancellation APIs). The test can be easily run like this:
>
>     cd src/test/modules/libpq_pipeline
>     make && ./libpq_pipeline cancel

Right now tests fails to build on windows with:

[15:45:10.518] src/interfaces/libpq/libpqdll.def : fatal error LNK1121: duplicate ordinal number '189' [c:\cirrus\libpq.vcxproj]
on fails tests on other platforms. See
https://cirrus-ci.com/build/4791821363576832


> NOTE: I have not tested this with GSS for the moment. My expectation is
> that using this new API with a GSS connection will result in a
> CONNECTION_BAD status when calling PQcancelStatus. The reason for this
> is that GSS reads will also need to communicate back that an EOF was
> found, just like I've done for TLS reads and unencrypted reads. Since in
> case of a cancel connection an EOF is actually expected, and should not
> be treated as an error.

The failures do not seem related to this.

Greetings,

Andres Freund

Commits

  1. postgres_fdw: re-issue cancel requests a few times if necessary.

  2. Make postgres_fdw's query_cancel test less flaky.

  3. postgres_fdw: Split out the query_cancel test to its own file

  4. Fix copy-paste mistake in PQcancelCreate

  5. Make libpqsrv_cancel's return const char *, not char *

  6. Stabilize postgres_fdw test

  7. libpq-be-fe-helpers.h: wrap new cancel APIs

  8. dblink/isolationtester/fe_utils: Use new cancel API

  9. Put libpq_pipeline cancel test back

  10. Hopefully make libpq_pipeline's new cancel test more reliable

  11. libpq: Add encrypted and non-blocking query cancellation routines

  12. libpq: Move pg_cancel to fe-cancel.c

  13. Add tests for libpq query cancellation APIs

  14. Add missing connection statuses to docs

  15. libpq: Change some static functions to extern

  16. libpq: Add pqReleaseConnHosts function

  17. libpq: Move cancellation related functions to fe-cancel.c

  18. Make spelling of cancelled/cancellation consistent

  19. Be more wary about OpenSSL not setting errno on error.

  20. libpq: Use modern socket flags, if available.

  21. Drop test view when done with it.

  22. Doc: add some doco about using the libpq_pipeline test module.

  23. postgres_fdw: Allow cancellation of transaction control commands.