Re: WAL compression setting after PostgreSQL LZ4 default change

> Based on this, I agree with the original suggestion to default to
>    zstd > lz4 > pglz
> I don't think we need to "tune" the compression levels for either of the
> algorithms. The defaults seem pretty reasonable.

Thank you for your test , It looks like Michael Paquier's suggestion was right—zstd doesn't have much difference in CPU consumption at default compression levels, and it achieves a higher compression ratio. On another note, I recall there was a patch discussing zstd compression for TOAST, but it hasn't been active for a long time. Since zstd offers a higher compression ratio, I think it's worth pushing this forward.