Re: [HACKERS] Patch to implement pg_current_logfile() function - Mailing list pgsql-hackers

From Robert Haas
Subject Re: [HACKERS] Patch to implement pg_current_logfile() function
Date
Msg-id CA+Tgmob290Um9PKgOa5aU-MBykB740ot2PaAj0bedasvVzgctw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Patch to implement pg_current_logfile() function  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: [HACKERS] Patch to implement pg_current_logfile() function  (Gilles Darold <gilles.darold@dalibo.com>)
List pgsql-hackers
On Wed, Feb 15, 2017 at 4:03 PM, Alvaro Herrera
<alvherre@2ndquadrant.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.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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