On 02-02-2016 10:22, Armor wrote:
> As we known, the name of current log file depends on the number of
> seconds (for simple, later I will call it last_syslogger_file_time)
> since Epoch when create new log file. So, for this feature, the key is
> how syslogger process pass last_syslogger_file_time to backend processes.
>
I didn't like the name. Let's call it syslogger_file_name. It describes
what the variable is (actual file name that syslogger is writing on).
> To pass last_syslogger_file_time, we have 2 solutions: 1, add a
> global variable to record last_syslogger_file_time which shared by
> backends and syslogger, so backends can get last_syslogger_file_time
> very easily; 2 syslogger process send last_syslogger_file_time to pgstat
> process when last_syslogger_file_time changes, just as other auxiliary
> processes send stat message to pgstat process, and pgstat process will
> write last_syslogger_file_time into stat file so that backend can
> get last_syslogger_file_time via reading this stat file.
>
I prefer (1) because (i) logfile name is not statistics and (ii) stats
collector could not respond in certain circumstances (and even discard
some messages).
-- Euler Taveira Timbira - http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento,
Suporte24x7 e Treinamento
