Re: pg_walfile_name_offset can return inconsistent values

On Fri, Nov 10, 2023 at 08:25:35AM +0900, Michael Paquier wrote:
> On Thu, Nov 09, 2023 at 04:14:07PM -0500, Bruce Momjian wrote:
> > Attached is the full patch that changes pg_walfile_name_offset() and
> > pg_walfile_name().  There is no need for doc changes.  We need to
> > document this as incompatible in case users are realying on the old
> > behavior for WAL archiving purposes.  If they want the old behavior they
> > need to check for an offset of zero and subtract one from the file name.
> 
> FWIW, I am not really convinced that there is a strong need to
> backpatch any of that.  There's a risk that some queries relying on
> the old behavior suddenly break after a minor release, and that's
> always annoying.  A HEAD-only change seems like a safer bet to me.

Yes, this cannot be backpatched, clearly.

> > Can someone check that all other calls to XLByteToPrevSeg() are correct?
> 
> On a quick check, all the other calls use that for end record LSNs, so
> that looks fine.

Thank you.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.