Make any query to system.local use WHERE clause

Full scan queries are slower even if there is only one record.

Author: dkropachev

examples/request_init_listener.py

@@ -68,8 +68,8 @@ def __str__(self):
 # attach a listener to this session
 ra = RequestAnalyzer(session)
 
-session.execute("SELECT release_version FROM system.local")
-session.execute("SELECT release_version FROM system.local")
+session.execute("SELECT release_version FROM system.local WHERE key='local'")
+session.execute("SELECT release_version FROM system.local WHERE key='local'")
 
 print(ra)
 # 2 requests (0 errors)

tests/integration/__init__.py

@@ -87,7 +87,7 @@ def get_server_versions():
 
     c = TestCluster()
     s = c.connect()
-    row = s.execute('SELECT cql_version, release_version FROM system.local').one()
+    row = s.execute("SELECT cql_version, release_version FROM system.local WHERE key='local'").one()
 
     cass_version = _tuple_version(row.release_version)
     cql_version = _tuple_version(row.cql_version)

tests/integration/advanced/test_auth.py

@@ -157,7 +157,7 @@ def connect_and_query(self, auth_provider, query=None):
         os.environ['KRB5_CONFIG'] = self.krb_conf
         self.cluster = TestCluster(auth_provider=auth_provider)
         self.session = self.cluster.connect()
-        query = query if query else "SELECT * FROM system.local"
+        query = query if query else "SELECT * FROM system.local WHERE key='local'"
         statement = SimpleStatement(query)
         rs = self.session.execute(statement)
         return rs
@@ -529,4 +529,4 @@ def test_connection_with_transitional_mode(self):
         @expected_result connect and query should be allowed
         """
         auth_provider = TransitionalModePlainTextAuthProvider()
-        self.assertIsNotNone(self.connect_and_query(auth_provider, query="SELECT * from system.local"))
+        self.assertIsNotNone(self.connect_and_query(auth_provider, query="SELECT * from system.local WHERE key='local'"))

tests/integration/advanced/test_unixsocketendpoint.py

@@ -71,4 +71,4 @@ def tearDownClass(cls):
 
     def test_unix_socket_connection(self):
         s = self.cluster.connect()
-        s.execute('select * from system.local')
+        s.execute("select * from system.local where key='local'")

tests/integration/cloud/test_cloud.py

@@ -62,7 +62,7 @@ def test_match_system_local(self):
 
         self.assertEqual(len(self.hosts_up()), 3)
         for host in self.cluster.metadata.all_hosts():
-            row = self.session.execute('SELECT * FROM system.local', host=host).one()
+            row = self.session.execute("SELECT * FROM system.local WHERE key='local'", host=host).one()
             self.assertEqual(row.host_id, host.host_id)
             self.assertEqual(row.rpc_address, host.broadcast_rpc_address)
 

tests/integration/long/test_consistency.py

@@ -354,7 +354,7 @@ def test_pool_with_host_down(self):
             # Attempt a query against that node. It should complete
             cluster2 = TestCluster(contact_points=all_contact_points)
             session2 = cluster2.connect()
-            session2.execute("SELECT * FROM system.local")
+            session2.execute("SELECT * FROM system.local WHERE key='local'")
         finally:
             cluster2.shutdown()
             start(node_to_stop)

tests/integration/long/test_ipv6.py

@@ -80,7 +80,7 @@ class IPV6ConnectionTest(object):
     def test_connect(self):
         cluster = TestCluster(connection_class=self.connection_class, contact_points=['::1'], connect_timeout=10)
         session = cluster.connect()
-        future = session.execute_async("SELECT * FROM system.local")
+        future = session.execute_async("SELECT * FROM system.local WHERE key='local'")
         future.result()
         self.assertEqual(future._current_host.address, '::1')
         cluster.shutdown()

tests/integration/long/test_ssl.py

@@ -193,7 +193,7 @@ def test_can_connect_with_ssl_long_running(self):
         # attempt a few simple commands.
 
         for i in range(8):
-            rs = session.execute("SELECT * FROM system.local")
+            rs = session.execute("SELECT * FROM system.local WHERE key='local'")
             time.sleep(10)
 
         cluster.shutdown()

tests/integration/simulacron/test_connection.py

@@ -464,14 +464,14 @@ def test_driver_recovers_nework_isolation(self):
         for host in cluster.metadata.all_hosts():
             self.assertIn(host, listener.hosts_marked_down)
 
-        self.assertRaises(NoHostAvailable, session.execute, "SELECT * from system.local")
+        self.assertRaises(NoHostAvailable, session.execute, "SELECT * from system.local WHERE key='local'")
 
         clear_queries()
         prime_request(AcceptConnections())
 
         time.sleep(idle_heartbeat_timeout + idle_heartbeat_interval + 2)
 
-        self.assertIsNotNone(session.execute("SELECT * from system.local"))
+        self.assertIsNotNone(session.execute("SELECT * from system.local WHERE key='local'"))
 
     def test_max_in_flight(self):
         """ Verify we don't exceed max_in_flight when borrowing connections or sending heartbeats """

tests/integration/simulacron/utils.py

@@ -125,7 +125,7 @@ def prime_server_versions(self):
         if DSE_VERSION:
             system_local_row["dse_version"] = DSE_VERSION.base_version
         column_types = {"cql_version": "ascii", "release_version": "ascii"}
-        system_local = PrimeQuery("SELECT cql_version, release_version FROM system.local",
+        system_local = PrimeQuery("SELECT cql_version, release_version FROM system.local WHERE key='local'",
                                   rows=[system_local_row],
                                   column_types=column_types)