Hi!
I'm guessing are looking for:
https://www.postgresql.org/docs/12/runtime-config-replication.html
26.2.6. Replication Slots
Replication slots provide an automated way to ensure that the master
does not remove WAL segments until they have been received by all
standbys, and that the master does not remove rows which could cause a
recovery conflict even when the standby is disconnected.
Using replication slot can cause pg_wal directoy to occupy all free disk space
and after that server stop respondig.
This is spelled out here:
https://www.postgresql.org/docs/12/warm-standby.html#STREAMING-REPLICATION
"If you use streaming replication without file-based continuous
archiving, the server might recycle old WAL segments before the standby
has received them. If this occurs, the standby will need to be
reinitialized from a new base backup. You can avoid this by setting
wal_keep_segments to a value large enough to ensure that WAL segments
are not recycled too early, or by configuring a replication slot for the
standby.
Will wal_keep_segments keep segments also if named replication slot is lot
used ?
Andrus.
