Re: recovery_connections cannot start (was Re: master in standby mode croaks)

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Simon Riggs <simon@2ndquadrant.com>, Kevin Grittner <Kevin.Grittner@wicourts.gov>, Fujii Masao <masao.fujii@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2010-04-26T13:03:14Z
Lists: pgsql-hackers
On Mon, Apr 26, 2010 at 8:05 AM, Heikki Linnakangas
<heikki.linnakangas@enterprisedb.com> wrote:
> Tom Lane wrote:
>> Personally I agree with your objection to "crash" but not with the
>> objection to "standby".  Maybe this would be appropriate:
>>
>>       wal_mode = minimal | archive | hot_standby
>
> Ok, here's a patch implementing this proposal. It adds a new wal_mode
> setting, leaving archive_mode as it is. If you try to enable
> archive_mode when wal_mode is 'minimal', you get a warning and
> archive_mode is silently ignored. Likewise streaming replication
> connections are not allowed if wal_mode is 'minimal'.
> recovery_connections now does nothing in the master.
>
> A bit more bikeshedding before I commit this:
>
> * Should an invalid combination throw an ERROR and refuse to start,
> instead of just warning?

I think so.  Otherwise silent breakage is a real possibility.

> * How about naming the parameter wal_level instead of wal_mode? That
> would better convey that the higher levels add stuff on top of the lower
> levels, instead of having different modes that are somehow mutually
> exclusive.

That works for me.

...Robert