Re: Doc about how to set max_wal_senders when setting minimal wal_level

I would suggest a wording more like:

"A precondition for using minimal WAL is to disable WAL archiving and streaming replication by setting max_wal_senders to 0, and archive_mode to off."

While accurate, the phrase "you must set" just doesn't feel right to me.  I also don't like how the proposed sentence (either one) is added separately as opposed to being included in the immediately preceding paragraph.  While this limited patch is probably sufficient I would suggest trying to work out a slightly larger patch the improves the wording on the entire existing paragraph while incorporating the reference to max_wal_senders.

Note, we seem to be missing the documentation of the default setting for archive_mode.

In addition, max_wal_senders could also be changed, adding a sentence like:

"If setting max_wal_senders to 0 consider also reducing the amount of WAL produced by changing wal_level to minimal."

At least insofar as core is concerned without a wal sender the additional wal of replica is not actually able to be leveraged as pg_basebackup will not work (at noted in its own description).

David J.