Don't connect to nodes that are ignored by the load balancing policy

Sylvain Lebresne · Sylvain Lebresne · commit 14cc5de3b3a2 · 2014-02-25T17:42:20.000+01:00
JAVA-270 #fixes
diff --git a/driver-core/CHANGELOG.rst b/driver-core/CHANGELOG.rst
@@ -14,6 +14,8 @@ CHANGELOG
 - [bug] Use date string in query build to work-around CASSANDRA-6718 (JAVA-264)
 - [bug] Always return the PreparedStatement object that is cache internally (JAVA-263)
 - [bug] Fix race when multiple connect are done in parallel (JAVA-261)
+- [bug] Don't connect at all to nodes that are ignored by the load balancing
+  policy (JAVA-270)
 
 
 1.0.5:
diff --git a/driver-core/src/main/java/com/datastax/driver/core/Cluster.java b/driver-core/src/main/java/com/datastax/driver/core/Cluster.java
@@ -1020,14 +1020,30 @@ public void onAdd(final Host host) {
             if (isShutdown.get())
                 return;
 
+            // Adds to the load balancing first and foremost, as doing so might change the decision
+            // it will make for distance() on that node (not likely but we leave that possibility).
+            // This does mean the policy may start returning that node for query plan, but as long
+            // as no pools have been created (below) this will be ignored by RequestHandler so it's fine.
+            loadBalancingPolicy().onAdd(host);
+
+            // Next, if the host should be ignored, well, ignore it.
+            if (loadBalancingPolicy().distance(host) == HostDistance.IGNORED) {
+                // We still mark the node UP though as it should be (and notifiy the listeners).
+                // We'll mark it down if we have  a notification anyway and we've documented that especially
+                // for IGNORED hosts, the isUp() method was a best effort guess
+                host.setUp();
+                for (Host.StateListener listener : listeners)
+                    listener.onAdd(host);
+                return;
+            }
+
             try {
                 prepareAllQueries(host);
             } catch (InterruptedException e) {
                 Thread.currentThread().interrupt();
                 // Don't propagate because we don't want to prevent other listener to run
             }
 
-            loadBalancingPolicy().onAdd(host);
             controlConnection.onAdd(host);
 
             List<ListenableFuture<Boolean>> futures = new ArrayList<ListenableFuture<Boolean>>(sessions.size());
