svn commit: r1426702 - /hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java

[la...@apache.org]

Author: larsh
Date: Sat Dec 29 04:16:12 2012
New Revision: 1426702

URL: http://svn.apache.org/viewvc?rev=1426702&view=rev
Log:
HBASE-7440 ReplicationZookeeper#addPeer is racy (Himanshu)

Modified:
    hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java

Modified: hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java
URL: http://svn.apache.org/viewvc/hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java?rev=1426702&r1=1426701&r2=1426702&view=diff
==============================================================================
--- hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java (original)
+++ hbase/trunk/hbase-server/src/main/java/org/apache/hadoop/hbase/replication/ReplicationZookeeper.java Sat Dec 29 04:16:12 2012
@@ -411,8 +411,12 @@ public class ReplicationZookeeper implem
       ZKUtil.createWithParents(this.zookeeper, this.peersZNode);
       ZKUtil.createAndWatch(this.zookeeper, ZKUtil.joinZNode(this.peersZNode, id),
         toByteArray(clusterKey));
+      // There is a race b/w PeerWatcher and ReplicationZookeeper#add method to create the
+      // peer-state znode. This happens while adding a peer.
+      // The peer state data is set as "ENABLED" by default.
+      ZKUtil.createNodeIfNotExistsAndWatch(this.zookeeper, getPeerStateNode(id),
+        ENABLED_ZNODE_BYTES);
       // A peer is enabled by default
-      ZKUtil.createAndWatch(this.zookeeper, getPeerStateNode(id), ENABLED_ZNODE_BYTES);
     } catch (KeeperException e) {
       throw new IOException("Unable to add peer", e);
     }
@@ -1067,7 +1071,10 @@ public class ReplicationZookeeper implem
   static boolean ensurePeerEnabled(final ZooKeeperWatcher zookeeper, final String path)
       throws NodeExistsException, KeeperException {
     if (ZKUtil.checkExists(zookeeper, path) == -1) {
-      ZKUtil.createAndWatch(zookeeper, path, ENABLED_ZNODE_BYTES);
+      // There is a race b/w PeerWatcher and ReplicationZookeeper#add method to create the
+      // peer-state znode. This happens while adding a peer.
+      // The peer state data is set as "ENABLED" by default.
+      ZKUtil.createNodeIfNotExistsAndWatch(zookeeper, path, ENABLED_ZNODE_BYTES);
       return true;
     }
     return false;