Disable undistribute_table for tenant tables

src/backend/distributed/commands/alter_table.c

@@ -380,6 +380,8 @@ UndistributeTable(TableConversionParameters *params)
 							   "because the table is not distributed")));
 	}
 
+	ErrorIfTenantTable(params->relationId, "undistribute_table");
+
 	if (!params->cascadeViaForeignKeys)
 	{
 		EnsureTableNotReferencing(params->relationId, UNDISTRIBUTE_TABLE);

src/test/regress/expected/schema_based_sharding.out

@@ -80,6 +80,9 @@ ERROR:  test_table is not allowed for update_distributed_table_colocation becaus
 -- verify we also don't allow colocate_with a tenant table
 SELECT update_distributed_table_colocation('regular_schema.test_table', colocate_with => 'tenant_2.test_table');
 ERROR:  test_table is not allowed for colocate_with because it is a tenant table
+-- verify we don't allow undistribute_table for tenant tables
+SELECT undistribute_table('tenant_2.test_table');
+ERROR:  test_table is not allowed for undistribute_table because it is a tenant table
 -- (on coordinator) verify that colocation id is set for empty tenants too
 SELECT colocationid > 0 FROM pg_dist_tenant_schema
 WHERE schemaid::regnamespace::text IN ('tenant_1', 'tenant_3');

src/test/regress/sql/schema_based_sharding.sql

@@ -59,6 +59,8 @@ SELECT citus_add_local_table_to_metadata('tenant_2.test_table');
 SELECT update_distributed_table_colocation('tenant_2.test_table', colocate_with => 'none');
 -- verify we also don't allow colocate_with a tenant table
 SELECT update_distributed_table_colocation('regular_schema.test_table', colocate_with => 'tenant_2.test_table');
+-- verify we don't allow undistribute_table for tenant tables
+SELECT undistribute_table('tenant_2.test_table');
 
 -- (on coordinator) verify that colocation id is set for empty tenants too
 SELECT colocationid > 0 FROM pg_dist_tenant_schema