Horton

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

Jelte Fennema <me@jeltef.nl>

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From: Jelte Fennema <me@jeltef.nl>
To: Jelte Fennema <Jelte.Fennema@microsoft.com>
Cc: Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut <peter@eisentraut.org>, Jacob Champion <jchampion@timescale.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2023-01-26T16:42:37Z
Lists: pgsql-hackers

Attachments

After discussing this patch privately with Andres I created a new
version of this patch.
The main changes are:
1. Build on top of a refactor to addrinfo handling I had done for
another patch of mine (libpq load balancing). This allows creation of
a fake addrinfo list, which made it possible to remove lots of special
cases for cancel requests from PQconnectPoll
2. Move -2 return value of pqReadData to a separate commit.
3. Move usage of new cancel APIs to a separate commit.
4. Move most of the logic that's specific to cancel requests to cancel
related functions, e.g. PQcancelPoll does more than simply forwarding
to PQconnectPoll now.
5. Copy over the connhost data from the original connection, instead
of assuming that it will be rebuilt identically in the cancel
connection. The main reason for this is that when/if the loadbalancing
patch gets merged, then it won't necessarily be rebuilt identically
anymore.

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.