Re: warning to publication created and wal_level is not set to logical

On Thu, Mar 21, 2019 at 07:45:59PM -0300, Lucas Viecelli wrote:
> Hi everyone,
>
> A very common question among new users is how wal_level works and it
> levels. I heard about some situations like that, a user create a new
> publication in its master database and he/she simply does not change
> wal_level to logical, sometimes, this person lost maintenance
> window, or a chance to restart postgres service, usually a
> production database, and it will discover that wal_level is not
> right just in subscription creation. Attempting to iterate between
> new (and even experienced) users with logical replication, I am
> sending a patch that when an PUBLICATION is created and the
> wal_level is different from logical prints a WARNING in console/log:

Is a WARNING sufficient? Maybe I'm misunderstanding something
important, but I think the attempt should fail with a HINT to set the
wal_level ahead of time.

Possibly in a separate patch, setting the wal_level to anything lower
than logical when publications exist should also fail.

Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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