Horton

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

Alexander Law <exclusion@gmail.com>

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From: Alexander Lakhin <exclusion@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>
Cc: Jelte Fennema-Nio <postgres@jeltef.nl>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Noah Misch <noah@leadboat.com>, Jacob Champion <jacob.champion@enterprisedb.com>, 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>, Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut <peter@eisentraut.org>, Justin Pryzby <pryzby@telsasoft.com>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Etsuro Fujita <etsuro.fujita@gmail.com>
Date: 2024-11-17T03:00:01Z
Lists: pgsql-hackers 
Hello Tom and Andres,

17.11.2024 05:33, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
>
>> Another failure in CI, that cleared up after a retry:
>> +WARNING:  could not get result of cancel request due to timeout
> Yeah.  This has been happening off-and-on in the buildfarm ever
> since we added that test.  I'm not sure if it's just "the test
> is unstable" or if it's telling us there's a problem with the
> cancel logic.  Scraping the last 3 months worth of buildfarm
> logs finds these instances:

Yes, I counted those bf failures at [1] too and posted my explanation
upthread [2].

[1] 
https://wiki.postgresql.org/wiki/Known_Buildfarm_Test_Failures#posgtres_fdw.2Fquery_cancel_fails_due_to_an_unexpected_warning_on_canceling_a_statement
[2] https://www.postgresql.org/message-id/c68225b4-fce9-3425-1534-a21a815d5846@gmail.com

Best regards,
Alexander

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.