Re: Create replication slot in pg_basebackup if requested and not yet present

On 8/18/17 05:28, Michael Banck wrote:
>>> Rebased, squashed and slighly edited version attached. I've added this
>>> to the 2017-07 commitfest now as well:
>>>
>>> https://commitfest.postgresql.org/14/1112/
>> Can you rebase this past some conflicting changes?
> Thanks for letting me know, PFA a rebased version.

I have reviewed the thread so far. I think there is general agreement
that something like this would be good to have.

I have not found any explanation, however, why the "if not exists"
behavior is desirable, let alone as the default. I can only think of
two workflows here: Either you have scripts for previous PG versions
that create the slot externally, in which can you omit --create, or you
use the new functionality to have pg_basebackup create the slot. I
don't see any use for pg_basebackup to opportunistically use a slot if
it happens to exist. Even if there is one, it should not be the
default. So please change that.

A minor point, I suggest to print the message about the replication slot
being created *after* the slot has been created. This aligns with how
logical replication subscriptions work. I don't see the need for
printing a message about temporary slots. Since they are temporary,
they will go away automatically, so there is nothing the user needs to
know there.

With these two changes, I think I'd be content with this patch.

--
Peter Eisentraut http://www.2ndQuadrant.com/
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