Improve the WARNING message for CREATE SUBSCRIPTION.

Author: Peter Smith
Reviewed-By: Alvaro Herrera, Tom Lane, Amit Kapila
Discussion: https://postgr.es/m/CAHut+PvqdqOanheWSHDyhQiF+Z-7w=-+k4U+bwbT=b6YQ_hrXQ@mail.gmail.com

src/backend/commands/subscriptioncmds.c

@@ -760,9 +760,8 @@ CreateSubscription(ParseState *pstate, CreateSubscriptionStmt *stmt,
 	}
 	else
 		ereport(WARNING,
-		/* translator: %s is an SQL ALTER statement */
-				(errmsg("tables were not subscribed, you will have to run %s to subscribe the tables",
-						"ALTER SUBSCRIPTION ... REFRESH PUBLICATION")));
+				(errmsg("subscription was created, but is not connected"),
+				 errhint("To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.")));
 
 	table_close(rel, RowExclusiveLock);
 

src/test/regress/expected/object_address.out

@@ -48,7 +48,8 @@ CREATE PUBLICATION addr_pub FOR TABLE addr_nsp.gentable;
 CREATE PUBLICATION addr_pub_schema FOR TABLES IN SCHEMA addr_nsp;
 RESET client_min_messages;
 CREATE SUBSCRIPTION regress_addr_sub CONNECTION '' PUBLICATION bar WITH (connect = false, slot_name = NONE);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 CREATE STATISTICS addr_nsp.gentable_stat ON a, b FROM addr_nsp.gentable;
 -- test some error cases
 SELECT pg_get_object_address('stone', '{}', '{}');

src/test/regress/expected/subscription.out

@@ -29,7 +29,8 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 ERROR:  publication name "foo" used more than once
 -- ok
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 COMMENT ON SUBSCRIPTION regress_testsub IS 'test subscription';
 SELECT obj_description(s.oid, 'pg_subscription') FROM pg_subscription s;
   obj_description  
@@ -98,7 +99,8 @@ CREATE SUBSCRIPTION regress_testsub2 CONNECTION 'dbname=regress_doesnotexist' PU
 ERROR:  subscription with slot_name = NONE must also set enabled = false
 -- ok - with slot_name = NONE
 CREATE SUBSCRIPTION regress_testsub3 CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (slot_name = NONE, connect = false);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 -- fail
 ALTER SUBSCRIPTION regress_testsub3 ENABLE;
 ERROR:  cannot enable subscription that does not have a slot name
@@ -109,7 +111,8 @@ CREATE SUBSCRIPTION regress_testsub4 CONNECTION 'dbname=regress_doesnotexist' PU
 ERROR:  unrecognized origin value: "foo"
 -- now it works
 CREATE SUBSCRIPTION regress_testsub4 CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (slot_name = NONE, connect = false, origin = none);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+ regress_testsub4
                                                                                          List of subscriptions
        Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
@@ -233,7 +236,8 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 ERROR:  binary requires a Boolean value
 -- now it works
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, binary = true);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
                                                                                          List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
@@ -256,7 +260,8 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 ERROR:  streaming requires a Boolean value
 -- now it works
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, streaming = true);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
                                                                                          List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
@@ -312,7 +317,8 @@ ALTER SUBSCRIPTION regress_testsub DROP PUBLICATION testpub1, testpub2 WITH (ref
 DROP SUBSCRIPTION regress_testsub;
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION mypub
        WITH (connect = false, create_slot = false, copy_data = false);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 ALTER SUBSCRIPTION regress_testsub ENABLE;
 -- fail - ALTER SUBSCRIPTION with refresh is not allowed in a transaction
 -- block or function
@@ -338,7 +344,8 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 ERROR:  two_phase requires a Boolean value
 -- now it works
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, two_phase = true);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
                                                                                          List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
@@ -362,7 +369,8 @@ ALTER SUBSCRIPTION regress_testsub SET (slot_name = NONE);
 DROP SUBSCRIPTION regress_testsub;
 -- two_phase and streaming are compatible.
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, streaming = true, two_phase = true);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
                                                                                          List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN 
@@ -377,7 +385,8 @@ CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUB
 ERROR:  disable_on_error requires a Boolean value
 -- now it works
 CREATE SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist' PUBLICATION testpub WITH (connect = false, disable_on_error = false);
-WARNING:  tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... REFRESH PUBLICATION to subscribe the tables
+WARNING:  subscription was created, but is not connected
+HINT:  To initiate replication, you must manually create the replication slot, enable the subscription, and refresh the subscription.
 \dRs+
                                                                                          List of subscriptions
       Name       |           Owner           | Enabled | Publication | Binary | Streaming | Two-phase commit | Disable on error | Origin | Synchronous commit |          Conninfo           | Skip LSN