Commit 387da18874 moved the code to put socket into non-blocking mode from socket_set_nonblocking() into the one-time initialization function, pq_init(). In socket_set_nonblocking(), there indeed was a risk of recursion on failure like the comment said, but in pq_init(), ERROR or FATAL is fine. There's even another elog(FATAL) just after this, if setting FD_CLOEXEC fails. Note that COMMERROR merely logged the error, it did not close the connection, so if putting the socket to non-blocking mode failed we would use the connection anyway. You might not immediately notice, because most socket operations in a regular backend wait for the socket to become readable/writable anyway. But e.g. replication will be quite broken. Backpatch to all supported versions. Discussion: https://www.postgresql.org/message-id/d40a5cd0-2722-40c5-8755-12e9e811fa3c@iki.fi
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/devel/
In particular, information about building PostgreSQL from the source
code can be found at:
https://www.postgresql.org/docs/devel/installation.html
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