Horton

Re: Back-patch use of unnamed POSIX semaphores for Linux?

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alex Hunsaker <badalex@gmail.com>, Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2016-12-07T23:27:46Z
Lists: pgsql-hackers 
Tom Lane wrote:

> Hmm ... after further experimentation, I still can't get this version of
> systemd (231) to do anything evil.  It turns out that Fedora ships it with
> KillUserProcesses turned off by default, and maybe having that on is a
> prerequisite for the other behavior?  But that doesn't make a lot of sense
> because we'd never be seeing the reports of databases moaning about lost
> semaphores if the processes got killed first.  Anyway, I see nothing bad
> happening if KillUserProcesses is off, while if it's on then the database
> gets shut down reasonably politely via SIGTERM.
> 
> Color me confused ... maybe systemd's behavior has changed?

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/ZNQW72UP36UAFMX53HPFFQTWTQDZVJ3M/

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Make the different Unix-y semaphore implementations ABI-compatible.

  2. Use unnamed POSIX semaphores, if available, on Linux and FreeBSD.