Don't allow to set replication slot_name as ''.

We don't allow to create replication slot_name as an empty string ('') via
SQL API pg_create_logical_replication_slot() but it is allowed to be set
via Alter Subscription command. This will lead to apply worker repeatedly
keep trying to stream data via slot_name '' and the user is not allowed to
create the slot with that name.

Author: Japin Li
Reviewed-By: Ranier Vilela, Amit Kapila
Backpatch-through: 10, where it was introduced
Discussion: https://postgr.es/m/MEYP282MB1669CBD98E721C77CA696499B61A9@MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM

diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c
index f05e86fa93648969ed0bdd42deb2640240faad33..6d3e870e641f0e0b29ee742507ca767d977f4a9e 100644 (file)
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -39,6 +39,7 @@
 
 #include "replication/logicallauncher.h"
 #include "replication/origin.h"
+#include "replication/slot.h"
 #include "replication/walreceiver.h"
 #include "replication/walsender.h"
 #include "replication/worker_internal.h"
@@ -145,6 +146,8 @@ parse_subscription_options(List *options, bool *connect, bool *enabled_given,
            /* Setting slot_name = NONE is treated as no slot name. */
            if (strcmp(*slot_name, "none") == 0)
                *slot_name = NULL;
+           else
+               ReplicationSlotValidateName(*slot_name, ERROR);
        }
        else if (strcmp(defel->defname, "copy_data") == 0 && copy_data)
        {

diff --git a/src/test/regress/expected/subscription.out b/src/test/regress/expected/subscription.out
index 4fcbf7efe97fa63b267bf0fc6fea9527aac92804..1bebfb1ade679fba11efdc53ccbe2b56fe93ecf5 100644 (file)
--- a/src/test/regress/expected/subscription.out
+++ b/src/test/regress/expected/subscription.out
@@ -86,6 +86,9 @@ ALTER SUBSCRIPTION testsub SET PUBLICATION testpub2, testpub3 WITH (refresh = fa
 ALTER SUBSCRIPTION testsub CONNECTION 'dbname=doesnotexist2';
 ALTER SUBSCRIPTION testsub SET (slot_name = 'newname');
 -- fail
+ALTER SUBSCRIPTION testsub SET (slot_name = '');
+ERROR:  replication slot name "" is too short
+-- fail
 ALTER SUBSCRIPTION doesnotexist CONNECTION 'dbname=doesnotexist2';
 ERROR:  subscription "doesnotexist" does not exist
 ALTER SUBSCRIPTION testsub SET (create_slot = false);

diff --git a/src/test/regress/sql/subscription.sql b/src/test/regress/sql/subscription.sql
index 36fa1bbac806639bbb6871934bd3890e1f59f147..b20eeb088d906b4f027157ad23f69b511b01a2bf 100644 (file)
--- a/src/test/regress/sql/subscription.sql
+++ b/src/test/regress/sql/subscription.sql
@@ -65,6 +65,9 @@ ALTER SUBSCRIPTION testsub SET PUBLICATION testpub2, testpub3 WITH (refresh = fa
 ALTER SUBSCRIPTION testsub CONNECTION 'dbname=doesnotexist2';
 ALTER SUBSCRIPTION testsub SET (slot_name = 'newname');
 
+-- fail
+ALTER SUBSCRIPTION testsub SET (slot_name = '');
+
 -- fail
 ALTER SUBSCRIPTION doesnotexist CONNECTION 'dbname=doesnotexist2';
 ALTER SUBSCRIPTION testsub SET (create_slot = false);