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Tom Lane f3a4d7e7c2 Distinguish wait-for-connection from wait-for-write-ready on Windows.
The API for WaitLatch and friends followed the Unix convention in which
waiting for a socket connection to complete is identical to waiting for
the socket to accept a write.  While Windows provides a select(2)
emulation that agrees with that, the native WaitForMultipleObjects API
treats them as quite different --- and for some bizarre reason, it will
report a not-yet-connected socket as write-ready.  libpq itself has so
far escaped dealing with this because it waits with select(), but in
libpqwalreceiver.c we want to wait using WaitLatchOrSocket.  The semantics
mismatch resulted in replication connection failures on Windows, but only
for remote connections (apparently, localhost connections complete
immediately, or at least too fast for anyone to have noticed the problem
in single-machine testing).

To fix, introduce an additional WL_SOCKET_CONNECTED wait flag for
WaitLatchOrSocket, which is identical to WL_SOCKET_WRITEABLE on
non-Windows, but results in waiting for FD_CONNECT events on Windows.

Ideally, we would also distinguish the two conditions in the API for
PQconnectPoll(), but changing that API at this point seems infeasible.
Instead, cheat by checking for PQstatus() == CONNECTION_STARTED to
determine that we're still waiting for the connection to complete.
(This is a cheat mainly because CONNECTION_STARTED is documented as an
internal state rather than something callers should rely on.  Perhaps
we ought to change the documentation ... but this patch doesn't.)

Per reports from Jobin Augustine and Igor Neyman.  Back-patch to v10
where commit 1e8a85009 exposed this longstanding shortcoming.

Andres Freund, minor fix and some code review/beautification by me

Discussion: https://postgr.es/m/CAHBggj8g2T+ZDcACZ2FmzX9CTxkWjKBsHd6NkYB4i9Ojf6K1Fw@mail.gmail.com
2017-08-15 11:07:57 -04:00
config Absorb -D_USE_32BIT_TIME_T switch from Perl, if relevant. 2017-08-14 11:48:59 -04:00
contrib Remove uses of "slave" in replication contexts 2017-08-10 22:55:41 -04:00
doc pg_dump: Add a --load-via-partition-root option. 2017-08-14 22:54:41 -04:00
src Distinguish wait-for-connection from wait-for-write-ready on Windows. 2017-08-15 11:07:57 -04:00
.dir-locals.el
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Allow .so minor version numbers above 9 in .gitignore. 2016-08-15 17:35:35 -04:00
aclocal.m4 Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
configure Stamp HEAD as 11devel. 2017-08-14 18:08:30 -04:00
configure.in Stamp HEAD as 11devel. 2017-08-14 18:08:30 -04:00
COPYRIGHT Update copyright for 2017 2017-01-03 12:37:53 -05:00
GNUmakefile.in Have "make coverage" recurse into contrib as well 2016-09-05 18:44:36 -03:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Prevent passing down MAKELEVEL/MAKEFLAGS from non-GNU make to GNU make. 2017-08-09 12:05:53 -04:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.