Re: BUG #7549: max_connections check should query master when starting standby

On Tue, Sep 18, 2012 at 3:51 AM, <petsku(at)petteriraty(dot)eu> wrote:
> The following bug has been logged on the website:
>
> Bug reference: 7549
> Logged by: Petteri Räty
> Email address: petsku(at)petteriraty(dot)eu
> PostgreSQL version: 9.2.0
> Operating system: Linux or OS X
> Description:
>
> On a streaming hot standby slave starting postgres:
>
>
> LOG: database system was interrupted while in recovery at log time
> 2012-09-17 21:29:31 EEST
> HINT: If this has occurred more than once some data might be corrupted and
> you might need to choose an earlier recovery target.
> LOG: entering standby mode
> FATAL: hot standby is not possible because max_connections = 20 is a lower
> setting than on the master server (its value was 100)
> LOG: startup process (PID 51494) exited with exit code 1
> LOG: aborting startup due to startup process failure
>
> It was indeed the case that the limit was lower on the slave but to resolve
> it I lowered the setting on the master:
>
> postgres=# SHOW max_connections;
> max_connections
> -----------------
> 20
> (1 row)
>
> The slave should allow resolving the issue by not only changes on the slave
> side but by checking if the master has been updated as well.

If you change the max_connections on the master, you need to take a
fresh backup from the master and start the standby from it.

Regards,

--
Fujii Masao