doc: Correct description of restart_lsn in pg_replication_slots
Previously the document explained that restart_lsn indicates the LSN of
oldest WAL won't be automatically removed during checkpoints. But
since v13 this was no longer true thanks to max_slot_wal_keep_size.
Back-patch to v13 where max_slot_wal_keep_size was added.
Author: Fujii Masao
Discussion:
@@ -11214,7 +11214,9 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
<para>
The address (<literal>LSN</literal>) of oldest WAL which still
might be required by the consumer of this slot and thus won't be
- automatically removed during checkpoints. <literal>NULL</literal>
+ automatically removed during checkpoints unless this LSN
+ gets behind more than <xref linkend="guc-max-slot-wal-keep-size"/>
+ from the current LSN. <literal>NULL</literal>
if the <literal>LSN</literal> of this slot has never been reserved.
</para></entry>
</row>
