Re: Different compression methods for FPI

On Mon, Jun 21, 2021 at 07:19:27PM -0500, Justin Pryzby wrote:
> The two similar, existing messages are:
>
> +#define NO_LZ4_SUPPORT() \
> + ereport(ERROR, \
> + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), \
> + errmsg("unsupported LZ4 compression method"), \
> + errdetail("This functionality requires the server to be built with lz4 support."), \
> + errhint("You need to rebuild PostgreSQL using --with-lz4.")))
>
> src/bin/pg_dump/pg_backup_archiver.c: fatal("cannot restore from compressed archive (compression not supported in this installation)");
> src/bin/pg_dump/pg_backup_archiver.c: pg_log_warning("archive is compressed, but this installation does not support compression -- no data will be available");
> src/bin/pg_dump/pg_dump.c: pg_log_warning("requested compression not available in this installation -- archive will be uncompressed");

The difference between the first message and the rest is that the
backend has much more room in terms of error verbosity while
xlogreader.c needs to worry also about the frontend. In this case, we
need to worry about the block involved and its LSN. Perhaps you have
a suggestion?
--
Michael