cql: reject ALTER tablets KS with repl opts

cql3/statements/alter_keyspace_statement.cc

@@ -50,6 +50,10 @@ void cql3::statements::alter_keyspace_statement::validate(query_processor& qp, c
         }
         try {
             auto ks = qp.db().find_keyspace(_name);
+            // TODO: the full tablets support will be implemented in https://github.com/scylladb/scylladb/issues/16129
+            if (ks.get_replication_strategy().uses_tablets() && !_attrs->get_replication_options().empty()) {
+                throw exceptions::invalid_request_exception("Changing replication options via ALTER KEYSPACE statement is not yet supported for keyspaces with tablets.");
+            }
             data_dictionary::storage_options current_options = ks.metadata()->get_storage_options();
             data_dictionary::storage_options new_options = _attrs->get_storage_options();
             if (!qp.proxy().features().keyspace_storage_options && !new_options.is_local_type()) {

docs/cql/ddl.rst

@@ -293,6 +293,17 @@ For instance::
 
 The supported options are the same as :ref:`creating a keyspace <create-keyspace-statement>`.
 
+ALTER KEYSPACE with Tablets :label-caution:`Experimental`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Modifying a keyspace with tablets enabled is not yet fully supported and all ``ALTER KEYSPACE`` statements specifying any replication option issued on a keyspace with tablets enabled are going to be rejected:
+
+.. code-block:: cql
+
+   cqlsh> CREATE KEYSPACE excalibur WITH replication = {'class': 'NetworkTopologyStrategy', 'DC1': 4} and tablets = {'initial': 8};
+   cqlsh> ALTER KEYSPACE excalibur WITH replication = {'class': 'NetworkTopologyStrategy', 'DC1': 3};
+   InvalidRequest: Error from server: code=2200 [Invalid query] message="Changing replication options via ALTER KEYSPACE statement is not yet supported for keyspaces with tablets."
+
 .. _drop-keyspace-statement:
 
 DROP KEYSPACE

test/cql-pytest/cassandra_tests/validation/operations/alter_test.py

@@ -222,6 +222,7 @@ def testAlterKeyspaceWithNoOptionThrowsConfigurationException(cql, test_keyspace
 
 # Test {@link ConfigurationException} thrown when altering a keyspace to
 # invalid DC option in replication configuration.
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def testAlterKeyspaceWithNTSOnlyAcceptsConfiguredDataCenterNames(cql, test_keyspace, this_dc):
     # Create a keyspace with expected DC name.
     with create_keyspace(cql, "replication={ 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 2 }") as ks:
@@ -231,6 +232,7 @@ def testAlterKeyspaceWithNTSOnlyAcceptsConfiguredDataCenterNames(cql, test_keysp
         # Mix valid and invalid, should throw an exception
         assert_invalid_throw_message_re(cql, ks, "Unrecognized strategy option {INVALID_DC} passed to .*NetworkTopologyStrategy for keyspace " + ks, ConfigurationException, "ALTER KEYSPACE %s WITH replication={ 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 2 , 'INVALID_DC': 1}")
 
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def testAlterKeyspaceWithMultipleInstancesOfSameDCThrowsSyntaxException(cql, test_keyspace, this_dc):
     # Create a keyspace
     with create_keyspace(cql, "replication={ 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 2 }") as ks:

test/cql-pytest/test_keyspace.py

@@ -97,11 +97,17 @@ def test_drop_keyspace_nonexistent(cql):
         cql.execute('DROP KEYSPACE nonexistent_keyspace')
 
 # Test trying to ALTER a keyspace.
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def test_alter_keyspace(cql, this_dc):
     with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
         cql.execute(f"ALTER KEYSPACE {keyspace} WITH REPLICATION = {{ 'class' : 'NetworkTopologyStrategy', '{this_dc}' : 3 }} AND DURABLE_WRITES = false")
 
+def test_alter_keyspace_without_providing_replication_options(cql, this_dc):
+    with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
+        cql.execute(f"ALTER KEYSPACE {keyspace} WITH DURABLE_WRITES = false")
+
 # Test trying to ALTER a keyspace with invalid options.
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def test_alter_keyspace_invalid(cql, this_dc):
     with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
         with pytest.raises(ConfigurationException):
@@ -130,6 +136,7 @@ def test_alter_keyspace_missing_rf(cql, this_dc, scylla_only, has_tablets):
 
 # Test trying to ALTER a keyspace with invalid options.
 # Reproduces #7595.
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def test_alter_keyspace_nonexistent_dc(cql, this_dc):
     with new_test_keyspace(cql, "WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', '" + this_dc + "' : 1 }") as keyspace:
         with pytest.raises(ConfigurationException):

test/cql-pytest/test_tablets.py

@@ -92,6 +92,7 @@ def test_tablets_can_be_explicitly_disabled(cql, skip_without_tablets):
         assert len(list(res)) == 0, "tablets replication strategy turned on"
 
 
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 def test_alter_changes_initial_tablets(cql, skip_without_tablets):
     ksdef = "WITH replication = {'class': 'NetworkTopologyStrategy', 'replication_factor': 1} AND tablets = {'initial': 1};"
     with new_test_keyspace(cql, ksdef) as keyspace:

test/topology_custom/test_tablets.py

@@ -22,6 +22,7 @@
 
 
 @pytest.mark.asyncio
+@pytest.mark.xfail(reason="Issue #16129; ALTER tablets KS doesn't support replication options")
 async def test_tablet_replication_factor_enough_nodes(manager: ManagerClient):
     cfg = {'enable_user_defined_functions': False,
            'experimental_features': ['tablets']}