Re: [HACKERS] Custom compression methods

On Sun, Mar 7, 2021 at 2:19 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>
> Earlier in this thread, I suggested to implement an option to pg_restore to
> avoid outputting compression, in order to allow restoring with a different
> compression (by using the default_toast_compression GUC). Now, it seems like
> that's even more important, to allow restoring into binaries --without-lz4.
> (the pg_dump isn't in LZ4 format, it just needs to not say "COMPRESSION LZ4").

IMHO, we have an option with pg_dump that should be sufficient, no?
but I agree that having such an option with restore will give more
flexibility basically, by using the same dump we can restore to binary
--with-lz4 as well as without-lz4 if such option exists with restore
as well. But it seems in pg_restore we process token by token so if
we want to implement such an option then I think we will have to parse
the complete string of CREATE TABLE command and remove the compression
option if it exists for any attribute. I am not sure whether providing
this option is worth the complexity?

> I think you're planning to allow the CREATE TABLE to succeed in any case, but
> it's not helpful if the DBA has to restore the schema, and then alter all the
> text columns to set PGLZ, and then restore the data and post-data.
>
> Also, I suggest to rename the pg_dump option:
> | --no-compression-methods do not dump compression methods
>
> I have a patch to pg_dump to support alternate compression in the dump itself
> (in addition to zlib), so the name will be confusing. I suggest
> --no-toast-compression, like the GUC. And the same for pg_restore.

Ok.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com