This documentation
+ <para>
+ Specify the maximum size of WAL files
+ that <link linkend="streaming-replication-slots">replication
+ slots</link> are allowed to retain in the
<filename>pg_wal</filename>
+ directory at checkpoint time.
+ If <varname>max_slot_wal_keep_size</varname> is zero (the default),
+ replication slots retain unlimited size of WAL files.
+ </para>
doesn't say anything about what happens when the limit is exceeded.
Does the system halt until the WAL is fetched from the slots? Do the
slots get invalidated?
Also, I don't think 0 is a good value for the default behavior. 0 would
mean that a slot is not allowed to retain any more WAL than already
exists anyway. Maybe we don't want to support that directly, but it's a
valid configuration. So maybe use -1 for infinity.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
