doc: Document some nuances of logical replication of TRUNCATE

diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index 1e7a54c8e3bb0f73f32e375b64c43e770c252c0b..59de6bcc0a8f6111398717e95c1a97662f334303 100644 (file)
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -371,6 +371,22 @@
     
    
 
+   
+    
+     Replication of TRUNCATE commands is supported, but
+     some care must be taken when truncating groups of tables connected by
+     foreign keys.  When replicating a truncate action, the subscriber will
+     truncate the same group of tables that was truncated on the publisher,
+     either explictly specified or implicitly collected via
+     CASCADE, minus tables that are not part of the
+     subscription.  This will work correctly if all affected tables are part
+     of the same subscription.  But if some tables to be truncated on the
+     subscriber have foreign-key links to tables that are not part of the same
+     (or any) subscription, then the application of the truncate action on the
+     subscriber will fail.
+    
+   
+
    
     
      Large objects (see ) are not replicated.