Re: syslog enabled causes random hangs?

""Arthur Ward"" <award(at)dominionsciences(dot)com> writes:
> I'm encountering strange hangs in postgresql backends at random moments.
> They seem to be associated with attempts to issue log entries via syslog.
> I have run backtraces on the hung backends a few times, and they routinely
> trace into system libraries where it looks like a stuck syslog call. So
> far, I haven't had this problem with any other apps, so I'm thinking it's
> a condition being aggravated by Postgres.
>
> The machines I'm seeing this on are RedHat 8 and Gentoo Linux machines
> (x86). We're running compiled-from-source 7.3.3 on both machines (by hand
> on the RH8 machine, and built by Gentoo's package manager, because it's a
> build-from-source distribution). On my Gentoo test boxes, it happens
> occasionally using syslog-ng 1.6.0_rc3 and glibc 2.3.2-r1. On the RedHat 8
> machine, it's sysklogd-1.4.1-10 and "glibc-devel-2.3.2-4.80.6". I switched
> to not using syslog on the RH8 machine because it was hanging backends
> quite regularly, and that's rather bad in production. :)
>
> Has anyone else had problems using the syslog option?
>
> I need to rebuild PostgreSQL on my test machine so I'll have unstripped
> binaries, but once that's done, I'll bring on the stack traces when I get
> another hang.

Try to put a "-" before the name of your log file, this say to syslogd to
not
flush each message on the disk, so your line should appear somethink like:

LOCAL0.* -/var/log/postgresql.log

Regards
Gaetano Mendola