Horton

Re: [EXTERNAL] Re: Add non-blocking version of PQcancel

Jelte Fennema-Nio <postgres@jeltef.nl>

View thread View on postgr.es
From: Jelte Fennema-Nio <postgres@jeltef.nl>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Noah Misch <noah@leadboat.com>, Jacob Champion <jacob.champion@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Denis Laxalde <denis.laxalde@dalibo.com>, vignesh C <vignesh21@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Greg Stark <stark@mit.edu>, "Gregory Stark (as CFM)" <stark.cfm@gmail.com>, Jelte Fennema <Jelte.Fennema@microsoft.com>, Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut <peter@eisentraut.org>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org, Etsuro Fujita <etsuro.fujita@gmail.com>
Date: 2024-03-28T09:31:30Z
Lists: pgsql-hackers 
On Wed, 27 Mar 2024 at 19:46, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
>
> On 2024-Mar-27, Alvaro Herrera wrote:
>
> > I changed it so that the error messages are returned as translated
> > phrases, and was bothered by the fact that if errors happen repeatedly,
> > the memory for them might be leaked.  Maybe this is fine depending on
> > the caller's memory context, but since it's only at most one string each
> > time, it's quite easy to just keep track of it so that we can release it
> > on the next.
>
> (Actually this sounds clever but fails pretty obviously if the caller
> does free the string, such as in a memory context reset.  So I guess we
> have to just accept the potential leakage.)

Your changes look good, apart from the prverror stuff indeed. If you
remove the prverror stuff again I think this is ready to commit.

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.