ReplicationQueuesZKImpl (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.replication.ReplicationStateZKBase
- - org.apache.hadoop.hbase.replication.ReplicationQueuesZKImpl

All Implemented Interfaces:

ReplicationQueues
```
@InterfaceAudience.Private
public class ReplicationQueuesZKImpl
extends ReplicationStateZKBase
implements ReplicationQueues
```
This class provides an implementation of the ReplicationQueues interface using Zookeeper. The base znode that this class works at is the myQueuesZnode. The myQueuesZnode contains a list of all outstanding WAL files on this region server that need to be replicated. The myQueuesZnode is the regionserver name (a concatenation of the region server’s hostname, client port and start code). For example: /hbase/replication/rs/hostname.example.org,6020,1234 Within this znode, the region server maintains a set of WAL replication queues. These queues are represented by child znodes named using there give queue id. For example: /hbase/replication/rs/hostname.example.org,6020,1234/1 /hbase/replication/rs/hostname.example.org,6020,1234/2 Each queue has one child znode for every WAL that still needs to be replicated. The value of these WAL child znodes is the latest position that has been replicated. This position is updated every time a WAL entry is replicated. For example: /hbase/replication/rs/hostname.example.org,6020,1234/1/23522342.23422 [VALUE: 254]

Field Summary

Fields
Modifier and Type	Field and Description
`private static org.apache.commons.logging.Log`	`LOG`
`private String`	`myQueuesZnode` Znode containing all replication queues for this region server.
`static String`	`RS_LOCK_ZNODE` Name of znode we use to lock during failover

Fields inherited from class org.apache.hadoop.hbase.replication.ReplicationStateZKBase
abortable, conf, DISABLED_ZNODE_BYTES, ENABLED_ZNODE_BYTES, ourClusterKey, peerStateNodeName, peersZNode, queuesZNode, replicationZNode, zookeeper

Constructor Summary

Constructors
Constructor and Description
`ReplicationQueuesZKImpl(ZooKeeperWatcher zk, org.apache.hadoop.conf.Configuration conf, Abortable abortable)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addLog(String queueId, String filename)` Add a new WAL file to the given queue.
`boolean`	`checkLockExists(String znode)`
`SortedMap<String,SortedSet<String>>`	`claimQueues(String regionserverZnode)` Take ownership for the set of queues belonging to a dead region server.
`private SortedMap<String,SortedSet<String>>`	`copyQueuesFromRS(String znode)` This methods copies all the wals queues from another region server and returns them all sorted per peer cluster (appended with the dead server's znode)
`private SortedMap<String,SortedSet<String>>`	`copyQueuesFromRSUsingMulti(String znode)` It "atomically" copies all the wals queues from another region server and returns them all sorted per peer cluster (appended with the dead server's znode).
`private void`	`deleteAnotherRSQueues(String regionserverZnode)` Delete all the replication queues for a given region server.
`List<String>`	`getAllQueues()` Get a list of all queues for this region server.
`List<String>`	`getListOfReplicators()` Get a list of all region servers that have outstanding replication queues.
`String`	`getLockZNode(String znode)`
`long`	`getLogPosition(String queueId, String filename)` Get the current position for a specific WAL in a given queue.
`List<String>`	`getLogsInQueue(String queueId)` Get a list of all WALs in the given queue.
`void`	`init(String serverName)` Initialize the region server replication queue interface.
`boolean`	`isThisOurZnode(String znode)` Checks if the provided znode is the same as this region server's
`boolean`	`lockOtherRS(String znode)` Try to set a lock in another region server's znode.
`(package private) static byte[]`	`lockToByteArray(String lockOwner)`
`void`	`removeAllQueues()` Remove all replication queues for this region server.
`void`	`removeLog(String queueId, String filename)` Remove an WAL file from the given queue.
`void`	`removeQueue(String queueId)` Remove a replication queue.
`void`	`setLogPosition(String queueId, String filename, long position)` Set the current position for a specific WAL in a given queue.

Methods inherited from class org.apache.hadoop.hbase.replication.ReplicationStateZKBase
getListOfReplicatorsZK, isPeerPath, peerExists, toByteArray

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - myQueuesZnode
```
private String myQueuesZnode
```
    Znode containing all replication queues for this region server.
  - RS_LOCK_ZNODE
```
public static final String RS_LOCK_ZNODE
```
    Name of znode we use to lock during failover
    
    See Also:
    Constant Field Values
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
- Constructor Detail
  - ReplicationQueuesZKImpl
```
public ReplicationQueuesZKImpl(ZooKeeperWatcher zk,
                       org.apache.hadoop.conf.Configuration conf,
                       Abortable abortable)
```
- Method Detail
  - init
```
public void init(String serverName)
          throws ReplicationException
```
    Description copied from interface: ReplicationQueues
    
    Initialize the region server replication queue interface.
    
    Specified by:
    
    init in interface ReplicationQueues
    
    Parameters:
    serverName - The server name of the region server that owns the replication queues this interface manages.
    
    Throws:
    
    ReplicationException
  - getListOfReplicators
```
public List<String> getListOfReplicators()
                                  throws ReplicationException
```
    Description copied from interface: ReplicationQueues
    
    Get a list of all region servers that have outstanding replication queues. These servers could be alive, dead or from a previous run of the cluster.
    
    Specified by:
    
    getListOfReplicators in interface ReplicationQueues
    
    Returns:
    a list of server names
    
    Throws:
    
    ReplicationException
  - removeQueue
```
public void removeQueue(String queueId)
```
    Description copied from interface: ReplicationQueues
    
    Remove a replication queue.
    
    Specified by:
    
    removeQueue in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue.
  - addLog
```
public void addLog(String queueId,
          String filename)
            throws ReplicationException
```
    Description copied from interface: ReplicationQueues
    
    Add a new WAL file to the given queue. If the queue does not exist it is created.
    
    Specified by:
    
    addLog in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue.
    filename - name of the WAL
    
    Throws:
    
    ReplicationException
  - removeLog
```
public void removeLog(String queueId,
             String filename)
```
    Description copied from interface: ReplicationQueues
    
    Remove an WAL file from the given queue.
    
    Specified by:
    
    removeLog in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue.
    filename - name of the WAL
  - setLogPosition
```
public void setLogPosition(String queueId,
                  String filename,
                  long position)
```
    Description copied from interface: ReplicationQueues
    
    Set the current position for a specific WAL in a given queue.
    
    Specified by:
    
    setLogPosition in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue
    filename - name of the WAL
    position - the current position in the file
  - getLogPosition
```
public long getLogPosition(String queueId,
                  String filename)
                    throws ReplicationException
```
    Description copied from interface: ReplicationQueues
    
    Get the current position for a specific WAL in a given queue.
    
    Specified by:
    
    getLogPosition in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue
    filename - name of the WAL
    
    Returns:
    the current position in the file
    
    Throws:
    
    ReplicationException
  - isThisOurZnode
```
public boolean isThisOurZnode(String znode)
```
    Description copied from interface: ReplicationQueues
    
    Checks if the provided znode is the same as this region server's
    
    Specified by:
    
    isThisOurZnode in interface ReplicationQueues
    
    Parameters:
    znode - to check
    
    Returns:
    if this is this rs's znode
  - claimQueues
```
public SortedMap<String,SortedSet<String>> claimQueues(String regionserverZnode)
```
    Description copied from interface: ReplicationQueues
    
    Take ownership for the set of queues belonging to a dead region server.
    
    Specified by:
    
    claimQueues in interface ReplicationQueues
    
    Parameters:
    regionserverZnode - the id of the dead region server
    
    Returns:
    A SortedMap of the queues that have been claimed, including a SortedSet of WALs in each queue. Returns an empty map if no queues were failed-over.
  - removeAllQueues
```
public void removeAllQueues()
```
    Description copied from interface: ReplicationQueues
    
    Remove all replication queues for this region server.
    
    Specified by:
    
    removeAllQueues in interface ReplicationQueues
  - getLogsInQueue
```
public List<String> getLogsInQueue(String queueId)
```
    Description copied from interface: ReplicationQueues
    
    Get a list of all WALs in the given queue.
    
    Specified by:
    
    getLogsInQueue in interface ReplicationQueues
    
    Parameters:
    queueId - a String that identifies the queue
    
    Returns:
    a list of WALs, null if this region server is dead and has no outstanding queues
  - getAllQueues
```
public List<String> getAllQueues()
```
    Description copied from interface: ReplicationQueues
    
    Get a list of all queues for this region server.
    
    Specified by:
    
    getAllQueues in interface ReplicationQueues
    
    Returns:
    a list of queueIds, null if this region server is dead and has no outstanding queues
  - lockOtherRS
```
public boolean lockOtherRS(String znode)
```
    Try to set a lock in another region server's znode.
    
    Parameters:
    znode - the server names of the other server
    
    Returns:
    true if the lock was acquired, false in every other cases
  - getLockZNode
```
public String getLockZNode(String znode)
```
  - checkLockExists
```
public boolean checkLockExists(String znode)
                        throws org.apache.zookeeper.KeeperException
```
    Throws:
    
    org.apache.zookeeper.KeeperException
  - deleteAnotherRSQueues
```
private void deleteAnotherRSQueues(String regionserverZnode)
```
    Delete all the replication queues for a given region server.
    
    Parameters:
    regionserverZnode - The znode of the region server to delete.
  - copyQueuesFromRSUsingMulti
```
private SortedMap<String,SortedSet<String>> copyQueuesFromRSUsingMulti(String znode)
```
    It "atomically" copies all the wals queues from another region server and returns them all sorted per peer cluster (appended with the dead server's znode).
    
    Parameters:
    znode - pertaining to the region server to copy the queues from
    
    Returns:
    WAL queues sorted per peer cluster
  - copyQueuesFromRS
```
private SortedMap<String,SortedSet<String>> copyQueuesFromRS(String znode)
```
    This methods copies all the wals queues from another region server and returns them all sorted per peer cluster (appended with the dead server's znode)
    
    Parameters:
    znode - server names to copy
    
    Returns:
    all wals for all peers of that cluster, null if an error occurred
  - lockToByteArray
```
static byte[] lockToByteArray(String lockOwner)
```
    Parameters:
    lockOwner -
    
    Returns:
    Serialized protobuf of lockOwner with pb magic prefix prepended suitable for use as content of an replication lock during region server fail over.

Class ReplicationQueuesZKImpl

Field Summary

Fields inherited from class org.apache.hadoop.hbase.replication.ReplicationStateZKBase

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.replication.ReplicationStateZKBase

Methods inherited from class java.lang.Object

Field Detail

myQueuesZnode

RS_LOCK_ZNODE

LOG

Constructor Detail

ReplicationQueuesZKImpl

Method Detail

init

getListOfReplicators

removeQueue

addLog

removeLog

setLogPosition

getLogPosition

isThisOurZnode

claimQueues

removeAllQueues

getLogsInQueue

getAllQueues

lockOtherRS

getLockZNode

checkLockExists

deleteAnotherRSQueues

copyQueuesFromRSUsingMulti

copyQueuesFromRS

lockToByteArray