Re: Patch: incorrect array offset in backend replication tar header

Brian Weaver <cmdrclueless@gmail.com> writes:
> If you're willing to wait a bit on me to code and test my extensions
> to pg_basebackup I will try to address some of the deficiencies as
> well add new features.

I think it's a mistake to try to handle these issues in the same patch
as feature extensions.  If you want to submit a patch for them, I'm
happy to let you do the legwork, but please keep it narrowly focused
on fixing file-format deficiencies.

The notes I had last night after examining pg_dump were:

magic number written incorrectly, but POSIX fields aren't filled anyway
(which is why tar tvf doesn't show them)

checksum code is brain-dead; no use in "lastSum" nor in looping

per spec, there should be 1024 zeroes not 512 at end of file;
this explains why tar whines about a "lone zero block" ...

Not sure which of these apply to pg_basebackup.

As far as the backwards compatibility issue goes, what seems like
a good idea after sleeping on it is (1) fix pg_dump in HEAD to emit
standard-compliant tar files; (2) fix pg_restore in HEAD and all back
branches to accept both the standard and the incorrect magic field.
This way, the only people with a compatibility problem would be those
trying to use by-then-ancient pg_restore versions to read 9.3 or later
pg_dump output.
        regards, tom lane