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HBASE-2874 Unnecessary double-synchronization in ZooKeeperWrapper 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@978801 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Michael Stack 2010-07-24 05:08:21 +00:00
parent b64c40daff
commit 01a251b50a
2 changed files with 49 additions and 47 deletions
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2
CHANGES.txt
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@ -799,6 +799,8 @@ Release 0.21.0 - Unreleased
HBASE-2873 Minor clean up in basescanner; fix a log and make deletes of
region processing run in order
HBASE-2830 NotServingRegionException shouldn't log a stack trace
HBASE-2874 Unnecessary double-synchronization in ZooKeeperWrapper
(Benoît Sigoure via Stack)
NEW FEATURES
HBASE-1961 HBase EC2 scripts

94
src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWrapper.java
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@ -58,39 +58,39 @@ import org.apache.zookeeper.data.Stat;
* This class provides methods to:
* - read/write/delete the root region location in ZooKeeper.
* - set/check out of safe mode flag.
*
*
* ------------------------------------------
* The following STATIC ZNodes are created:
* ------------------------------------------
* - parentZNode : All the HBase directories are hosted under this parent
* - parentZNode : All the HBase directories are hosted under this parent
* node, default = "/hbase"
* - rsZNode : This is the directory where the RS's create ephemeral
* nodes. The master watches these nodes, and their expiry
* - rsZNode : This is the directory where the RS's create ephemeral
* nodes. The master watches these nodes, and their expiry
* indicates RS death. The default location is "/hbase/rs"
*
*
* ------------------------------------------
* The following DYNAMIC ZNodes are created:
* ------------------------------------------
* - rootRegionZNode : Specifies the RS hosting root.
* - masterElectionZNode : ZNode used for election of the primary master when
* there are secondaries. All the masters race to write
* their addresses into this location, the one that
* - masterElectionZNode : ZNode used for election of the primary master when
* there are secondaries. All the masters race to write
* their addresses into this location, the one that
* succeeds is the primary. Others block.
* - clusterStateZNode : Determines if the cluster is running. Its default
* location is "/hbase/shutdown". It always has a value
* of "up". If present with the valus, cluster is up
* and running. If deleted, the cluster is shutting
* - clusterStateZNode : Determines if the cluster is running. Its default
* location is "/hbase/shutdown". It always has a value
* of "up". If present with the valus, cluster is up
* and running. If deleted, the cluster is shutting
* down.
* - rgnsInTransitZNode : All the nodes under this node are names of regions
* in transition. The first byte of the data for each
* of these nodes is the event type. This is used to
* - rgnsInTransitZNode : All the nodes under this node are names of regions
* in transition. The first byte of the data for each
* of these nodes is the event type. This is used to
* deserialize the rest of the data.
*/
public class ZooKeeperWrapper implements Watcher {
protected static final Log LOG = LogFactory.getLog(ZooKeeperWrapper.class);
// instances of the watcher
private static Map<String,ZooKeeperWrapper> INSTANCES =
private static Map<String,ZooKeeperWrapper> INSTANCES =
new HashMap<String,ZooKeeperWrapper>();
// lock for ensuring a singleton per instance type
private static Lock createLock = new ReentrantLock();
@ -112,13 +112,13 @@ public class ZooKeeperWrapper implements Watcher {
* Specifies the RS hosting root
*/
private final String rootRegionZNode;
/*
* This is the directory where the RS's create ephemeral nodes. The master
* watches these nodes, and their expiry indicates RS death.
/*
* This is the directory where the RS's create ephemeral nodes. The master
* watches these nodes, and their expiry indicates RS death.
*/
private final String rsZNode;
/*
* ZNode used for election of the primary master when there are secondaries.
* ZNode used for election of the primary master when there are secondaries.
*/
private final String masterElectionZNode;
/*
@ -127,14 +127,14 @@ public class ZooKeeperWrapper implements Watcher {
public final String clusterStateZNode;
/*
* Regions that are in transition
*/
*/
private final String rgnsInTransitZNode;
/*
* List of ZNodes in the unassgined region that are already being watched
*/
private Set<String> unassignedZNodesWatched = new HashSet<String>();
private List<Watcher> listeners = Collections.synchronizedList(new ArrayList<Watcher>());
private List<Watcher> listeners = new ArrayList<Watcher>();
// return the singleton given the name of the instance
public static ZooKeeperWrapper getInstance(Configuration conf, String name) {
@ -185,7 +185,7 @@ public class ZooKeeperWrapper implements Watcher {
}
sessionTimeout = conf.getInt("zookeeper.session.timeout", 60 * 1000);
reconnectToZk();
parentZNode = conf.get(HConstants.ZOOKEEPER_ZNODE_PARENT, HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT);
String rootServerZNodeName = conf.get("zookeeper.znode.rootserver", "root-region-server");
@ -200,7 +200,7 @@ public class ZooKeeperWrapper implements Watcher {
masterElectionZNode = getZNode(parentZNode, masterAddressZNodeName);
clusterStateZNode = getZNode(parentZNode, stateZNodeName);
}
public void reconnectToZk() throws IOException {
try {
LOG.info("Reconnecting to zookeeper");
@ -216,7 +216,7 @@ public class ZooKeeperWrapper implements Watcher {
} catch (InterruptedException e) {
LOG.error("<" + instanceName + ">" + "Error closing ZK connection: " + e);
throw new IOException(e);
}
}
}
public synchronized void registerListener(Watcher watcher) {
@ -748,11 +748,11 @@ public class ZooKeeperWrapper implements Watcher {
LOG.warn("<" + instanceName + ">" + "Failed to delete " + rsZNode + " znodes in ZooKeeper: " + e);
}
}
/**
* @return the number of region server znodes in the RS directory
*/
public int getRSDirectoryCount() {
public int getRSDirectoryCount() {
Stat stat = null;
try {
stat = zooKeeper.exists(rsZNode, false);
@ -1072,19 +1072,19 @@ public class ZooKeeperWrapper implements Watcher {
throw new IOException(e);
}
}
/**
* Given a region name and some data, this method creates a new the region
* znode data under the UNASSGINED znode with the data passed in. This method
* Given a region name and some data, this method creates a new the region
* znode data under the UNASSGINED znode with the data passed in. This method
* will not update data for existing znodes.
*
*
* @param regionName - encoded name of the region
* @param data - new serialized data to update the region znode
*/
private void createUnassignedRegion(String regionName, byte[] data) {
String znode = getZNode(getRegionInTransitionZNode(), regionName);
if(LOG.isDebugEnabled()) {
// check if this node already exists -
// check if this node already exists -
// - it should not exist
// - if it does, it should be in the CLOSED state
if(exists(znode, true)) {
@ -1096,7 +1096,7 @@ public class ZooKeeperWrapper implements Watcher {
LOG.error("Error reading data for " + znode);
}
if(oldData == null) {
LOG.debug("While creating UNASSIGNED region " + regionName + " exists with no data" );
LOG.debug("While creating UNASSIGNED region " + regionName + " exists with no data" );
}
else {
LOG.debug("While creating UNASSIGNED region " + regionName + " exists, state = " + (HBaseEventType.fromByte(oldData[0])));
@ -1104,7 +1104,7 @@ public class ZooKeeperWrapper implements Watcher {
}
else {
if(data == null) {
LOG.debug("Creating UNASSIGNED region " + regionName + " with no data" );
LOG.debug("Creating UNASSIGNED region " + regionName + " with no data" );
}
else {
LOG.debug("Creating UNASSIGNED region " + regionName + " in state = " + (HBaseEventType.fromByte(data[0])));
@ -1118,10 +1118,10 @@ public class ZooKeeperWrapper implements Watcher {
}
/**
* Given a region name and some data, this method updates the region znode
* data under the UNASSGINED znode with the latest data. This method will
* Given a region name and some data, this method updates the region znode
* data under the UNASSGINED znode with the latest data. This method will
* update the znode data only if it already exists.
*
*
* @param regionName - encoded name of the region
* @param data - new serialized data to update the region znode
*/
@ -1132,7 +1132,7 @@ public class ZooKeeperWrapper implements Watcher {
LOG.error("Cannot update " + znode + " - node does not exist" );
return;
}
Stat stat = new Stat();
byte[] oldData = null;
try {
@ -1174,10 +1174,10 @@ public class ZooKeeperWrapper implements Watcher {
}
/**
* This method will create a new region in transition entry in ZK with the
* speficied data if none exists. If one already exists, it will update the
* This method will create a new region in transition entry in ZK with the
* speficied data if none exists. If one already exists, it will update the
* data with whatever is passed in.
*
*
* @param regionName - encoded name of the region
* @param data - serialized data for the region znode
*/
@ -1228,8 +1228,8 @@ public class ZooKeeperWrapper implements Watcher {
}
/**
* Atomically adds a watch and reads data from the unwatched znodes in the
* UNASSGINED region. This works because the master is the only person
* Atomically adds a watch and reads data from the unwatched znodes in the
* UNASSGINED region. This works because the master is the only person
* deleting nodes.
* @param znode
* @return
@ -1258,22 +1258,22 @@ public class ZooKeeperWrapper implements Watcher {
}
return newNodes;
}
public static class ZNodePathAndData {
private String zNodePath;
private byte[] data;
public ZNodePathAndData(String zNodePath, byte[] data) {
this.zNodePath = zNodePath;
this.data = data;
}
public String getzNodePath() {
return zNodePath;
}
public byte[] getData() {
return data;
}
}
}