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 cc4c1b47e4ee05d5903d63a4fc4148787bb2e74d..22ae9823288975be489726815f2e843395760ba3 100644 (file)
--- a/src/backend/commands/subscriptioncmds.c
+++ b/src/backend/commands/subscriptioncmds.c
@@ -173,6 +173,8 @@ parse_subscription_options(ParseState *pstate, List *stmt_options,
            /* Setting slot_name = NONE is treated as no slot name. */
            if (strcmp(opts->slot_name, "none") == 0)
                opts->slot_name = NULL;
+           else
+               ReplicationSlotValidateName(opts->slot_name, ERROR);
        }
        else if (IsSet(supported_opts, SUBOPT_COPY_DATA) &&
                 strcmp(defel->defname, "copy_data") == 0)

diff --git a/src/test/regress/expected/subscription.out b/src/test/regress/expected/subscription.out
index ad6b4e4bd35fa661fd2a2e3ffba5555b08ceb06e..67f92b38787622db608d812afe9dd44b2c27123d 100644 (file)
--- a/src/test/regress/expected/subscription.out
+++ b/src/test/regress/expected/subscription.out
@@ -86,6 +86,9 @@ ALTER SUBSCRIPTION regress_testsub SET PUBLICATION testpub2, testpub3 WITH (refr
 ALTER SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist2';
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = 'newname');
 -- fail
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = '');
+ERROR:  replication slot name "" is too short
+-- fail
 ALTER SUBSCRIPTION regress_doesnotexist CONNECTION 'dbname=regress_doesnotexist2';
 ERROR:  subscription "regress_doesnotexist" does not exist
 ALTER SUBSCRIPTION regress_testsub SET (create_slot = false);

diff --git a/src/test/regress/sql/subscription.sql b/src/test/regress/sql/subscription.sql
index b7328714072114873e8e44a8326d694b4cc60e24..88743ab33bdf419d3d83fef5720e195fb946b71c 100644 (file)
--- a/src/test/regress/sql/subscription.sql
+++ b/src/test/regress/sql/subscription.sql
@@ -65,6 +65,9 @@ ALTER SUBSCRIPTION regress_testsub SET PUBLICATION testpub2, testpub3 WITH (refr
 ALTER SUBSCRIPTION regress_testsub CONNECTION 'dbname=regress_doesnotexist2';
 ALTER SUBSCRIPTION regress_testsub SET (slot_name = 'newname');
 
+-- fail
+ALTER SUBSCRIPTION regress_testsub SET (slot_name = '');
+
 -- fail
 ALTER SUBSCRIPTION regress_doesnotexist CONNECTION 'dbname=regress_doesnotexist2';
 ALTER SUBSCRIPTION regress_testsub SET (create_slot = false);