You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@hbase.apache.org by "Ted Yu (JIRA)" <ji...@apache.org> on 2012/12/27 05:34:12 UTC
[jira] [Commented] (HBASE-7440) ReplicationZookeeper#addPeer is
racy
[ https://issues.apache.org/jira/browse/HBASE-7440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13539824#comment-13539824 ]
Ted Yu commented on HBASE-7440:
-------------------------------
{code}
+ // There is a race b/w PeerWatcher and ReplicationZookeeper#add method to create the peer-state znode.
{code}
Wrap long line above.
{code}
+ } catch (KeeperException.NodeExistsException nee) {
+ LOG.warn("StateNode for " + peerStateNode
{code}
Shall we verify that the node carries data of PeerState.ENABLED ?
For the change in ReplicationZookeeper.java, similar comment applies in case of KeeperException.NodeExistsException.
> ReplicationZookeeper#addPeer is racy
> ------------------------------------
>
> Key: HBASE-7440
> URL: https://issues.apache.org/jira/browse/HBASE-7440
> Project: HBase
> Issue Type: Bug
> Components: Replication
> Affects Versions: 0.94.3
> Reporter: Himanshu Vashishtha
> Assignee: Himanshu Vashishtha
> Fix For: 0.96.0, 0.94.4
>
> Attachments: HBASE-7440-v0.patch
>
>
> While adding a peer, ReplicationZK does the znodes creation in three transactions. Create :
> a) peers znode
> b) peerId specific znode, and
> c) peerState znode
> There is a PeerWatcher which invokes getPeer() (after steps b) and c)). If it happens that while adding a peer, the control flows to getPeer() and step c) has not been processed, it may results in a state where the peer will not be added. This happens while running TestMasterReplication#testCyclicReplication().
> {code}
> 2012-12-26 07:36:35,187 INFO [RegionServer:0;p0120.XXXXX,38423,1356536179470-EventThread] zookeeper.RecoverableZooKeeper(447): Node /2/replication/peers/1/peer-state already exists and this is not a retry
> 2012-12-26 07:36:35,188 ERROR [RegionServer:0;p0120.XXXXX,38423,1356536179470-EventThread] regionserver.ReplicationSourceManager$PeersWatcher(527): Error while adding a new peer
> org.apache.zookeeper.KeeperException$NodeExistsException: KeeperErrorCode = NodeExists for /2/replication/peers/1/peer-state
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:119)
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
> at org.apache.zookeeper.ZooKeeper.create(ZooKeeper.java:783)
> at org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.createNonSequential(RecoverableZooKeeper.java:428)
> at org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.create(RecoverableZooKeeper.java:410)
> at org.apache.hadoop.hbase.zookeeper.ZKUtil.createAndWatch(ZKUtil.java:1044)
> at org.apache.hadoop.hbase.replication.ReplicationPeer.startStateTracker(ReplicationPeer.java:82)
> at org.apache.hadoop.hbase.replication.ReplicationZookeeper.getPeer(ReplicationZookeeper.java:344)
> at org.apache.hadoop.hbase.replication.ReplicationZookeeper.connectToPeer(ReplicationZookeeper.java:307)
> at org.apache.hadoop.hbase.replication.regionserver.ReplicationSourceManager$PeersWatcher.nodeChildrenChanged(ReplicationSourceManager.java:519)
> at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.process(ZooKeeperWatcher.java:315)
> at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:519)
> at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:495)
> 2012-12-26 07:36:35,188 DEBUG [RegionServer:0;p0120.XXXXX,55742,1356536171947-EventThread] zookeeper.ZKUtil(1545): regionserver:55742-0x13bd7db39580004 Retrieved 36 byte(s) of data from znode /1/hbaseid; data=9ce66123-d3e8-4ae9-a249-afe03...
> {code}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira