Zstd compression

[Krysztophe]

The following parameter silently and you get a dump with gzip:6 (default):

compress_level = zstd:9

The code seems to accept only an int, and you can put toto without raising an error or a warning!

The workaround is to ignore compress_level and to add this:

pg_dump_options = '-Z std:9'

Zstd/lz4 are so nice that this is shame that it needs a workaround.

Ideas:

• raise a warning if compress_level is not recognized
• add compress_algorithm (that would perhaps make it easier to raise an error for PG<16)
• modify compress_level to accept zstd:9

[orgrim]

Hi,

This sounds interesting, I think it's better and more intuitive to implement to same behavior as pg_dump itself, so I prefer the "just the level" to get gzip and "method:level" to choose zstd or other.

Regards