Re: Add LZ4 compression in pg_dump

On Thu, Jan 26, 2023 at 11:24:47AM +0000, gkokolatos@pm.me wrote:
> I gave this a little bit of thought. I think that ReadHead should not
> emit a warning, or at least not this warning as it is slightly misleading.
> It implies that it will automatically turn off data restoration, which is
> false. Further ahead, the code will fail with a conflicting error message
> stating that the compression is not available.
> 
> Instead, it would be cleaner both for the user and the maintainer to
> move the check in RestoreArchive and make it the sole responsible for
> this logic.

-    pg_fatal("cannot restore from compressed archive (compression not supported in this installation)");
+    pg_fatal("cannot restore data from compressed archive (compression not supported in this installation)");
Hmm.  I don't mind changing this part as you suggest.

-#ifndef HAVE_LIBZ
-       if (AH->compression_spec.algorithm == PG_COMPRESSION_GZIP)
-               pg_fatal("archive is compressed, but this installation does not support compression");
-#endif
However I think that we'd better keep the warning, as it can offer a
hint when using pg_restore -l not built with compression support if
looking at a dump that has been compressed.
--
Michael