Re: [HACKERS] pg_resetwal is broken if run from v10 against older version of PG data directory

Michael Paquier <michael.paquier@gmail.com> writes:
> On Mon, May 29, 2017 at 9:00 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So we need to prevent this, not try to make it work.  I don't think
>> we can insist on a version match in pg_control, because part of the
>> point of pg_resetxlog/pg_resetwal is to recover if pg_control is
>> unreadable.  But I think we could look at PG_VERSION, which is only a
>> text file.

> Agreed. Shouldn't this be back-patched? PG_CONTROL_VERSION has not
> been bumped between 9.4 and 9.5. Attached is a patch for HEAD.

Yeah, I'm thinking it would be a good idea to enforce this in all
branches.  Your patch looks sane in a quick once-over, but I didn't
test it.
        regards, tom lane