Re: Patch to implement pg_current_logfile() function

Le 16/02/2017 à 16:13, Robert Haas a écrit :
> On Wed, Feb 15, 2017 at 4:03 PM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
>> So what is going on here is that SysLogger_Start() wants to unlink the
>> current-logfile file if the collector is not enabled. This should
>> probably be split out into a separate new function, for two reasons:
>> first, it doesn't seem good idea to have SysLogger_Start do something
>> other than start the logger; and second, so that we don't have a syscall
>> on each ServerLoop iteration. That new function should be called from
>> some other place -- perhaps reaper() and just before entering
>> ServerLoop, so that the file is deleted if the syslogger goes away or is
>> not started.
> I think it's sufficient to just remove the file once on postmaster
> startup before trying to launch the syslogger for the first time.
> logging_collector is PGC_POSTMASTER, so if it's not turned on when the
> cluster first starts, it can't be activated later. If it dies, that
> doesn't seem like a reason to remove the file. We're going to restart
> the syslogger, and when we do, it can update the file.
>

I've attached a new full v30 patch that include last patch from Karl.
Now the current_logfile file is removed only at postmaster startup, just
before launching the syslogger for the first time.

--
Gilles Darold
Consultant PostgreSQL
http://dalibo.com - http://dalibo.org