Horton

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

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: Jelte Fennema-Nio <postgres@jeltef.nl>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Thomas Munro <thomas.munro@gmail.com>, Denis Laxalde <denis.laxalde@dalibo.com>, Greg Stark <stark@mit.edu>, Tom Lane <tgl@sss.pgh.pa.us>, "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" <pgsql-hackers@lists.postgresql.org>
Date: 2024-01-28T03:15:08Z
Lists: pgsql-hackers 
On Fri, 26 Jan 2024 at 22:22, Jelte Fennema-Nio <postgres@jeltef.nl> wrote:
>
> On Fri, 26 Jan 2024 at 13:11, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> > I wonder, would it make sense to put all these new functions in a
> > separate file fe-cancel.c?
>
>
> Okay I tried doing that. I think the end result is indeed quite nice,
> having all the cancellation related functions together in a file. But
> it did require making a bunch of static functions in fe-connect
> extern, and adding them to libpq-int.h. On one hand that seems fine to
> me, on the other maybe that indicates that this cancellation logic
> makes sense to be in the same file as the other connection functions
> (in a sense, connecting is all that a cancel request does).

CFBot shows that the patch has few compilation errors as in [1]:
[17:07:07.621] /usr/bin/ld:
../../../src/fe_utils/libpgfeutils.a(cancel.o): in function
`handle_sigint':
[17:07:07.621] cancel.c:(.text+0x50): undefined reference to `PQcancel'
[17:07:07.621] /usr/bin/ld:
../../../src/fe_utils/libpgfeutils.a(cancel.o): in function
`SetCancelConn':
[17:07:07.621] cancel.c:(.text+0x10c): undefined reference to `PQfreeCancel'
[17:07:07.621] /usr/bin/ld: cancel.c:(.text+0x114): undefined
reference to `PQgetCancel'
[17:07:07.621] /usr/bin/ld:
../../../src/fe_utils/libpgfeutils.a(cancel.o): in function
`ResetCancelConn':
[17:07:07.621] cancel.c:(.text+0x148): undefined reference to `PQfreeCancel'
[17:07:07.621] /usr/bin/ld:
../../../src/fe_utils/libpgfeutils.a(connect_utils.o): in function
`disconnectDatabase':
[17:07:07.621] connect_utils.c:(.text+0x2fc): undefined reference to
`PQcancelConn'
[17:07:07.621] /usr/bin/ld: connect_utils.c:(.text+0x307): undefined
reference to `PQcancelSend'
[17:07:07.621] /usr/bin/ld: connect_utils.c:(.text+0x30f): undefined
reference to `PQcancelFinish'
[17:07:07.623] /usr/bin/ld: ../../../src/interfaces/libpq/libpq.so:
undefined reference to `PQcancelPoll'
[17:07:07.626] collect2: error: ld returned 1 exit status
[17:07:07.626] make[3]: *** [Makefile:31: pg_amcheck] Error 1
[17:07:07.626] make[2]: *** [Makefile:45: all-pg_amcheck-recurse] Error 2
[17:07:07.626] make[2]: *** Waiting for unfinished jobs....
[17:07:08.126] /usr/bin/ld: ../../../src/interfaces/libpq/libpq.so:
undefined reference to `PQcancelPoll'
[17:07:08.130] collect2: error: ld returned 1 exit status
[17:07:08.131] make[3]: *** [Makefile:42: initdb] Error 1
[17:07:08.131] make[2]: *** [Makefile:45: all-initdb-recurse] Error 2
[17:07:08.492] /usr/bin/ld: ../../../src/interfaces/libpq/libpq.so:
undefined reference to `PQcancelPoll'
[17:07:08.495] collect2: error: ld returned 1 exit status
[17:07:08.496] make[3]: *** [Makefile:50: pg_basebackup] Error 1
[17:07:08.496] make[2]: *** [Makefile:45: all-pg_basebackup-recurse] Error 2
[17:07:09.060] /usr/bin/ld: parallel.o: in function `sigTermHandler':
[17:07:09.060] parallel.c:(.text+0x1aa): undefined reference to `PQcancel'

Please post an updated version for the same.

[1] - https://cirrus-ci.com/task/6210637211107328

Regards,
Vignesh

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.