Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Jelte Fennema-Nio <postgres@jeltef.nl>, 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>, 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: 2024-04-03T21:29:44Z
Lists: pgsql-hackers 
Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Great, thanks for looking.  Pushed now, I'll be closing the commitfest
> entry shortly.

On my machine, headerscheck does not like this:

$ src/tools/pginclude/headerscheck --cplusplus
In file included from /tmp/headerscheck.4gTaW5/test.cpp:3:
./src/include/libpq/libpq-be-fe-helpers.h: In function 'char* libpqsrv_cancel(PGconn*, TimestampTz)':
./src/include/libpq/libpq-be-fe-helpers.h:393:10: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
   return "out of memory";
          ^~~~~~~~~~~~~~~
./src/include/libpq/libpq-be-fe-helpers.h:421:13: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
     error = "cancel request timed out";
             ^~~~~~~~~~~~~~~~~~~~~~~~~~

The second part of that could easily be fixed by declaring "error" as
"const char *".  As for the first part, can we redefine the whole
function as returning "const char *"?  (If not, this coding is very
questionable anyway.)

			regards, tom lane

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.