Re: refactoring basebackup.c

On Fri, Jan 28, 2022 at 12:48 PM Jeevan Ladhe
<jeevan(dot)ladhe(at)enterprisedb(dot)com> wrote:
> I have attached the latest rebased version of the LZ4 server-side compression
> patch on the recent commits. This patch also introduces the compression level
> and adds a tap test.

In view of this morning's commit of
d45099425eb19e420433c9d81d354fe585f4dbd6 I think the threshold for
committing this patch has gone up. We need to make it support
decompression with LZ4 on the client side, as we now have for gzip.

Other comments:

- Even if we were going to support LZ4 only on the server side, surely
it's not right to refuse --compress lz4 and --compress client-lz4 at
the parsing stage. I don't even think the message you added to main()
is reachable.

- In the new test case you set decompress_flags but according to the
documentation I have here, -m is for multiple files (and so should not
be needed here) and -d is for decompression (which is what we want
here). So I'm confused why this is like this.

Other than that this seems like it's in pretty good shape.

> Also, while adding the lz4 case in the pg_verifybackup/t/008_untar.pl, I found
> an unused variable {have_zlib}. I have attached a cleanup patch for that as well.

This part seems clearly correct, so I have committed it.

--
Robert Haas
EDB: http://www.enterprisedb.com