3c1c82d406
Winsock only signals an FD_CLOSE event once if the other end of the socket shuts down gracefully. Because each WaitLatchOrSocket() call constructs and destroys a new event handle every time, with unlucky timing we can lose it and hang. We get away with this only if the other end disconnects non-gracefully, because FD_CLOSE is repeatedly signaled in that case. To fix this design flaw in our Windows socket support fundamentally, we'd probably need to rearchitect it so that a single event handle exists for the lifetime of a socket, or switch to completely different multiplexing or async I/O APIs. That's going to be a bigger job and probably wouldn't be back-patchable. This brute force kludge closes the race by explicitly polling with MSG_PEEK before sleeping. Back-patch to all supported releases. This should hopefully clear up some random build farm and CI hang failures reported over the years. It might also allow us to try using graceful shutdown in more places again (reverted in commit 29992a6) to fix instability in the transmission of FATAL error messages, but that isn't done by this commit. Reported-by: Tom Lane <tgl@sss.pgh.pa.us> Tested-by: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/176008.1715492071%40sss.pgh.pa.us
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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.