Re: Log rotation

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > What versions of syslog fsync, and where is the syslog.conf option. I
> > don't see it on FreeBSD or Linux.
>
> It's a per-output-file option. My Linux manpage for syslogd quoth
>
> The - may only be used to prefix a filename if you want to omit
> sync'ing the file after every write to it.
>
> I believe this notation is inherited from BSD. I don't see anything
> about it in the HPUX man page for syslogd, though.

I see no mention of that flag in Free/NetBSD, or bsdi. I do see a
mention in Red Hat 9.

Looking at my syslog source code, the only lines that get fsync'ed are
lines from /dev/klog (kernel log messages). I think non-kernel messages
use the /var/run/log socket.

syslogd manual page says:

Syslogd reads messages from the LOCAL domain socket /var/run/log, from an
Internet domain socket specified in /etc/services, and from the special
device /dev/klog (to read kernel messages). Messages received on the In-
ternet and LOCAL domain sockets may be NULL terminated and may include a
single trailing newline, any other non-printable characters are encoded
into a visible representation by strvisx(3).

I wonder if this fsync for PostgreSQL messages is some change made to
Linux syslog.

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