Merge pull request #570 from datastax/531

PYTHON-531 - don't stall schema agreement on ignored hosts

cassandra/cluster.py

@@ -1161,7 +1161,7 @@ class Cluster(object):
         if distance == HostDistance.IGNORED:
             log.debug("Not adding connection pool for new host %r because the "
                       "load balancing policy has marked it as IGNORED", host)
-            self._finalize_add(host)
+            self._finalize_add(host, set_up=False)
             return
 
         futures_lock = Lock()
@@ -1203,9 +1203,10 @@ class Cluster(object):
         if not have_future:
             self._finalize_add(host)
 
-    def _finalize_add(self, host):
-        # mark the host as up and notify all listeners
-        host.set_up()
+    def _finalize_add(self, host, set_up=True):
+        if set_up:
+            host.set_up()
+
         for listener in self.listeners:
             listener.on_add(host)
 
@@ -2568,13 +2569,14 @@ class ControlConnection(object):
             if local_row.get("schema_version"):
                 versions[local_row.get("schema_version")].add(local_address)
 
+        lbp = self._cluster.load_balancing_policy
         for row in peers_result:
             schema_ver = row.get('schema_version')
             if not schema_ver:
                 continue
             addr = self._rpc_from_peer_row(row)
             peer = self._cluster.metadata.get_host(addr)
-            if peer and peer.is_up:
+            if peer and peer.is_up and lbp.distance(peer) != HostDistance.IGNORED:
                 versions[schema_ver].add(addr)
 
         if len(versions) == 1: