Handle change of slot name in logical replication apply

Since change of slot name is a supported operation, handle it more
gracefully, instead of in the this-should-not-happen way.

Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>

diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index bbf3506be04db63cb5150223f4efc0f524bda2eb..d6986f59c1c0a4b09b4c231805f201bfb2509d71 100644 (file)
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -1350,6 +1350,21 @@ reread_subscription(void)
                proc_exit(0);
        }
 
+       /*
+        * We need to make new connection to new slot if slot name has changed
+        * so exit here as well if that's the case.
+        */
+       if (strcmp(newsub->slotname, MySubscription->slotname) != 0)
+       {
+               ereport(LOG,
+                               (errmsg("logical replication worker for subscription \"%s\" will "
+                                               "restart because the replication slot name was changed",
+                                               MySubscription->name)));
+
+               walrcv_disconnect(wrconn);
+               proc_exit(0);
+       }
+
        /*
         * Exit if publication list was changed. The launcher will start
         * new worker.
@@ -1382,8 +1397,7 @@ reread_subscription(void)
        }
 
        /* Check for other changes that should never happen too. */
-       if (newsub->dbid != MySubscription->dbid ||
-               strcmp(newsub->slotname, MySubscription->slotname) != 0)
+       if (newsub->dbid != MySubscription->dbid)
        {
                elog(ERROR, "subscription %u changed unexpectedly",
                         MyLogicalRepWorker->subid);