Clarify the usage of max_replication_slots on the subscriber side.

It was not clear in the docs that the max_replication_slots is also used
to track replication origins on the subscriber side.

Author: Paul Martinez
Reviewed-by: Amit Kapila
Backpatch-through: 10 where logical replication was introduced
Discussion: https://postgr.es/m/CACqFVBZgwCN_pHnW6dMNCrOS7tiHCw6Retf_=U2Vvj3aUSeATw@mail.gmail.com

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b5718fc1366055351ab094eeed239f74c1010ff7..967de73596f7c7cafebb5396e143a3e93c0221c4 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4001,6 +4001,17 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
          to replica or higher to allow replication slots to
          be used.
         
+
+        
+         On the subscriber side, specifies how many replication origins (see
+         ) can be tracked simultaneously,
+         effectively limiting how many logical replication subscriptions can
+         be created on the server. Setting it a lower value than the current
+         number of tracked replication origins (reflected in
+         pg_replication_origin_status,
+         not pg_replication_origin)
+         will prevent the server from starting.
+        
        
       
 

diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index 9cd3f3fbb3d9561f9d07436c11cd226608a25335..e95d446dacb08a3a7ad059fd1fca59b22e98eb15 100644 (file)
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -603,11 +603,12 @@
 
   
    The subscriber also requires the max_replication_slots
-   to be set.  In this case it should be set to at least the number of
-   subscriptions that will be added to the subscriber, plus some reserve for
-   table synchronization.  max_logical_replication_workers
-   must be set to at least the number of subscriptions, again plus some reserve
-   for the table synchronization.  Additionally the max_worker_processes
+   be set to configure how many replication origins can be tracked.  In this
+   case it should be set to at least the number of subscriptions that will be
+   added to the subscriber, plus some reserve for table synchronization.
+   max_logical_replication_workers must be set to at least
+   the number of subscriptions, again plus some reserve for the table
+   synchronization.  Additionally the max_worker_processes
    may need to be adjusted to accommodate for replication workers, at least
    (max_logical_replication_workers
    + 1).  Note that some extensions and parallel queries