Re: [Patch] Make pg_checksums skip foreign tablespace directories

On Fri, Jan 31, 2020 at 05:39:36PM +0900, Kyotaro Horiguchi wrote:
> At Fri, 31 Jan 2020 17:30:43 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
>> I don't think that is a problem right away, of course. It looks good
>> to me except for the possible excessive exclusion.  So, I don't object
>> it if we don't mind that.
> 
> That's a bit wrong.  All the discussion is only on excludeFiles.  I
> think we should refrain from letting more files match to
> nohecksumFiles.

I am not sure what you are saying here.  Are you saying that we should
not use a prefix matching for that part?  Or are you saying that we
should not touch this list at all?

Please note that pg_internal.init is listed within noChecksumFiles in
basebackup.c, so we would miss any temporary pg_internal.init.PID if
we don't check after the file prefix and the base backup would issue
extra WARNING messages, potentially masking messages that could
matter.  So let's fix that as well.

I agree that a side effect of this change would be to discard anything
prefixed with "backup_label" or "tablespace_map", including any old,
renamed files.  Do you know of any backup solutions which could be
impacted by that?  I am adding David Steele and Stephen Frost in CC so
as they can comment based on their experience in this area.  I recall
that backrest stuff uses the replication protocol, but I may be
wrong.
--
Michael