Re: Windows: Wrong error message at connection termination

Hello Tom,
29.11.2021 22:16, Tom Lane wrote:
> Hm, yeah, that discussion seems to have slipped through the cracks.
> Not sure why it didn't end up in pushing something.
>
> After re-reading that thread and re-studying relevant Windows
> documentation [1][2], I think the main open question is whether
> we need to issue shutdown() or not, and if so, whether to use
> SD_BOTH or just SD_SEND. I'm inclined to prefer not calling
> shutdown(), because [1] is self-contradictory as to whether it
> can block, and [2] is pretty explicit that it's not necessary.
>
> regards, tom lane
>
> [1] https://docs.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-shutdown
> [2] https://docs.microsoft.com/en-us/windows/win32/winsock/graceful-shutdown-linger-options-and-socket-closure-2
I've tested the close-only patch with pg_sleep() in pqReadData(), and it
works too. So I wonder how to understand "To assure that all data is
sent and received on a connected socket before it is closed, an
application should use shutdown to close connection before calling
closesocket." in [1].
Maybe they mean that shutdown should be used before, but not after
closesocket ). Or maybe the Windows' behaviour somehow evolved over
time. (With the patch I cannot reproduce the FATAL message loss even on
Windows 2012 R2.) So without a practical evidence of the importance of
shutdown() I'm inclined to a more simple solution too.

As to 268313a95, back in 2003 it was possible to compile server on
Windows only using Cygwin (though you could compile libpq with Visual C,
see [3]). So "#ifdef WIN32" that is proposed now, will not affect that
scenario anyway.

Best regards,
Alexander

[3]
https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob_plain;f=doc/src/sgml/install-win32.sgml;hb=268313a95