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

On Fri, Sep 28, 2012 at 12:45 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Magnus Hagander <magnus(at)hagander(dot)net> writes:
>> Ah, yeah, that should also work I guess. But you could also just leave
>> the the data in the temporary tarfile the whole time. IIRC, you can
>> just cat one tarfile to the end of another one, right?
>
> Not if they're written according to spec, I think. There is an EOF
> marker consisting of 2 blocks of zeroes (which pg_dump is failing to
> create correctly, but that's a bug not a feature). Possibly you could
> strip the EOF marker though, if the file join code is allowed to be
> something smarter than "cat".

Hmm. Yeah. It seems gnu tar has "--concatenate".... Not sure if it's
in the standard or a GNU extension though. But it says:

"
However, tar archives incorporate an end-of-file marker which must be
removed if the concatenated archives are to be read properly as one
archive. `--concatenate' removes the end-of-archive marker from the
target archive before each new archive is appended. If you use cat to
combine the archives, the result will not be a valid tar format
archive. If you need to retrieve files from an archive that was added
to using the cat utility, use the --ignore-zeros (-i) option.
"

--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/