Re: pg_rewind in contrib

On 1/6/15 7:17 PM, Andres Freund wrote:
>> One problem is that it doesn't use the replication protocol,
>> > so the setup is going to be inconsistent with pg_basebackup.  Maybe the
>> > replication protocol could be extended to provide the required data.
> I'm not particularly bothered by the requirement of also requiring a
> normal, not replication, connection. In most cases that'll already be
> allowed.

I don't agree.  We have separated out replication access, especially in
pg_hba.conf and with the replication role attribute, for a reason.  (I
hope there was a reason; I don't remember.)  It is not unreasonable to
set things up so that non-replication access is only from the
application tier, and replication access is only from within the
database tier.

Now we're saying, well, we didn't really mean that, in order to use the
latest replication management tools, you also need to open up
non-replication access, but we assume you already do that anyway.

Now I understand that making pg_rewind work over a replication
connection is a lot more work, and maybe we don't want to spend it, at
least right now.  But then we either need to document this as an
explicit deficiency and think about fixing it later, or we should
revisit how replication access control is handled.