Re: Reduce the time to know trigger_file's existence

On Mon, Sep 3, 2012 at 2:19 AM, togetinfo mail <togetinfomail(at)gmail(dot)com> wrote:
> We are trying to introduce a thread that monitors the creation of the
> trigger_file. As and when the file is created, the process that monitors
> postgres server needs to be notified through the inotify API.
>
> This is to reduce the 3-4 seconds delay that exists with the current
> implementation in postgres. As per the current implementation, the thread
> checks for the existence of the file every 5 seconds. If the file got
> created just 1 second after the sleep, there is a wait time of 4 seconds
> before we know whether the file is present or not. We intend to avoid this
> delay by using inotify().
>
> PostgreSQL version number you are running: postgres 9.1.5
>
> How you installed PostgreSQL: Downloaded and compiled the sources
>
> Does anyone have suggestions on the appropriate place to add
> inotify_add_watch to achieve our objective?
> Thanks in advance.

I'm not in favor of this approach, because it will only work on Linux.

Also, can't you bypass this problem altogether by using "pg_ctl promote"?

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