Re: pgsql: Add suport for server-side LZ4 base backup compression.

On Sun, Feb 13, 2022 at 11:13:51AM -0500, Robert Haas wrote:
> Well, that's because I didn't realize that LZ4 might be set to
> something that doesn't work at all. So Michael's thing worked, but
> because it (in my view) fixed the problem in a more surprising place
> than I would have preferred, I made a commit later that turned out to
> break the buildfarm. So you can blame either one of us that you like.
> 
> Thanks, Michael, for preparing a patch.

Patch that was slightly wrong, as the tests of pg_verifybackup still
failed once I moved away the lz4 command in my environment because LZ4
gets set to an empty value.  I have checked this case locally, and
applied the patch to add the ./configure check, so copperhead should
get back to green.

A last thing, that has been mentioned by Andres upthread, is that we
should be able to remove the extra commands run with --version in the
tests of pg_basebackup, as of the attached.  I have not done that yet,
as it seems better to wait for copperhead first, and the tests of
pg_basebackup run before pg_verifybackup so I don't want to mask one
error for another in case the buildfarm says something.
--
Michael