ZkRegionMergeCoordination (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.coordination.ZkRegionMergeCoordination

All Implemented Interfaces:: RegionMergeCoordination

public class ZkRegionMergeCoordination
extends Object
implements RegionMergeCoordination

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class ZkRegionMergeCoordination.ZkRegionMergeDetails
ZK-based implementation.
- Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.coordination.RegionMergeCoordination
  RegionMergeCoordination.RegionMergeDetails

Nested Classes
Modifier and Type	Class and Description
`static class`	`ZkRegionMergeCoordination.ZkRegionMergeDetails` ZK-based implementation.

Field Summary

Fields
Modifier and Type Field and Description

private static org.apache.commons.logging.Log LOG

private CoordinatedStateManager manager

private ZooKeeperWatcher watcher

Fields
Modifier and Type	Field and Description
`private static org.apache.commons.logging.Log`	`LOG`
`private CoordinatedStateManager`	`manager`
`private ZooKeeperWatcher`	`watcher`

Constructor Summary

Constructors
Constructor and Description

ZkRegionMergeCoordination(CoordinatedStateManager manager, ZooKeeperWatcher watcher)

Constructors
Constructor and Description
`ZkRegionMergeCoordination(CoordinatedStateManager manager, ZooKeeperWatcher watcher)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clean(HRegionInfo hri)` This method is used during rollback
`void`	`completeRegionMergeTransaction(RegionServerServices services, HRegionInfo mergedRegionInfo, HRegion region_a, HRegion region_b, RegionMergeCoordination.RegionMergeDetails rmd, HRegion mergedRegion)` Finish off merge transaction
`void`	`confirmRegionMergeTransaction(HRegionInfo merged, HRegionInfo a, HRegionInfo b, ServerName serverName, RegionMergeCoordination.RegionMergeDetails rmd)` Confirm that the region merge can be performed
`RegionMergeCoordination.RegionMergeDetails`	`getDefaultDetails()`
`void`	`processRegionMergeRequest(HRegionInfo p, HRegionInfo hri_a, HRegionInfo hri_b, ServerName sn, RegionMergeCoordination.RegionMergeDetails rmd)`
`void`	`startRegionMergeTransaction(HRegionInfo region, ServerName serverName, HRegionInfo a, HRegionInfo b)` Creates a new ephemeral node in the PENDING_MERGE state for the merged region.
`private void`	`transitionMergingNode(HRegionInfo merged, HRegionInfo a, HRegionInfo b, ServerName serverName, RegionMergeCoordination.RegionMergeDetails rmd, EventType beginState, EventType endState)` Transitions an existing ephemeral node for the specified region which is currently in the begin state to be in the end state.
`void`	`waitForRegionMergeTransaction(RegionServerServices services, HRegionInfo mergedRegionInfo, HRegion region_a, HRegion region_b, RegionMergeCoordination.RegionMergeDetails details)` Wait for the merging node to be transitioned from pending_merge to merging by master.

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

- Field Detail
  - manager
```
private CoordinatedStateManager manager
```
  - watcher
```
private final ZooKeeperWatcher watcher
```
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
- Constructor Detail
  - ZkRegionMergeCoordination
```
public ZkRegionMergeCoordination(CoordinatedStateManager manager,
                         ZooKeeperWatcher watcher)
```
- Method Detail
  - getDefaultDetails
```
public RegionMergeCoordination.RegionMergeDetails getDefaultDetails()
```
    Specified by:
    
    getDefaultDetails in interface RegionMergeCoordination
  - waitForRegionMergeTransaction
```
public void waitForRegionMergeTransaction(RegionServerServices services,
                                 HRegionInfo mergedRegionInfo,
                                 HRegion region_a,
                                 HRegion region_b,
                                 RegionMergeCoordination.RegionMergeDetails details)
                                   throws IOException
```
    Wait for the merging node to be transitioned from pending_merge to merging by master. That's how we are sure master has processed the event and is good with us to move on. If we don't get any update, we periodically transition the node so that master gets the callback. If the node is removed or is not in pending_merge state any more, we abort the merge.
    
    Specified by:
    
    waitForRegionMergeTransaction in interface RegionMergeCoordination
    
    Throws:
    
    IOException
  - startRegionMergeTransaction
```
public void startRegionMergeTransaction(HRegionInfo region,
                               ServerName serverName,
                               HRegionInfo a,
                               HRegionInfo b)
                                 throws IOException
```
    Creates a new ephemeral node in the PENDING_MERGE state for the merged region. Create it ephemeral in case regionserver dies mid-merge.
    Does not transition nodes from other states. If a node already exists for this region, a KeeperException.NodeExistsException will be thrown.
    
    Specified by:
    
    startRegionMergeTransaction in interface RegionMergeCoordination
    
    Parameters:
    region - region to be created as offline
    serverName - server event originates from
    
    Throws:
    
    IOException
  - clean
```
public void clean(HRegionInfo hri)
```
    Description copied from interface: RegionMergeCoordination
    
    This method is used during rollback
    
    Specified by:
    
    clean in interface RegionMergeCoordination
    
    Parameters:
    hri - region to be rolled back
  - completeRegionMergeTransaction
```
public void completeRegionMergeTransaction(RegionServerServices services,
                                  HRegionInfo mergedRegionInfo,
                                  HRegion region_a,
                                  HRegion region_b,
                                  RegionMergeCoordination.RegionMergeDetails rmd,
                                  HRegion mergedRegion)
                                    throws IOException
```
    Description copied from interface: RegionMergeCoordination
    
    Finish off merge transaction
    
    Specified by:
    
    completeRegionMergeTransaction in interface RegionMergeCoordination
    
    Parameters:
    services - Used to online/offline regions.
    mergedRegionInfo - region
    region_a - merging region A
    region_b - merging region B
    rmd - region merge details
    
    Throws:
    
    IOException - If thrown, transaction failed. Call RegionMergeTransaction.rollback( Server, RegionServerServices)
  - confirmRegionMergeTransaction
```
public void confirmRegionMergeTransaction(HRegionInfo merged,
                                 HRegionInfo a,
                                 HRegionInfo b,
                                 ServerName serverName,
                                 RegionMergeCoordination.RegionMergeDetails rmd)
                                   throws IOException
```
    Description copied from interface: RegionMergeCoordination
    
    Confirm that the region merge can be performed
    
    Specified by:
    
    confirmRegionMergeTransaction in interface RegionMergeCoordination
    
    Parameters:
    merged - region
    a - merging region A
    b - merging region B
    serverName - server event originates from
    rmd - region merge details
    
    Throws:
    
    IOException - If thrown, transaction failed.
  - processRegionMergeRequest
```
public void processRegionMergeRequest(HRegionInfo p,
                             HRegionInfo hri_a,
                             HRegionInfo hri_b,
                             ServerName sn,
                             RegionMergeCoordination.RegionMergeDetails rmd)
                               throws IOException
```
    Specified by:
    
    processRegionMergeRequest in interface RegionMergeCoordination
    
    Parameters:
    p - region
    hri_a - merging region A
    hri_b - merging region B
    sn - server event originates from
    rmd - region merge details
    
    Throws:
    
    IOException
  - transitionMergingNode
```
private void transitionMergingNode(HRegionInfo merged,
                         HRegionInfo a,
                         HRegionInfo b,
                         ServerName serverName,
                         RegionMergeCoordination.RegionMergeDetails rmd,
                         EventType beginState,
                         EventType endState)
                            throws IOException
```
    Transitions an existing ephemeral node for the specified region which is currently in the begin state to be in the end state. Master cleans up the final MERGE znode when it reads it (or if we crash, zk will clean it up).
    Does not transition nodes from other states. If for some reason the node could not be transitioned, the method returns -1. If the transition is successful, the version of the node after transition is updated in details.
    This method can fail and return false for three different reasons:
    - Node for this region does not exist
    - Node for this region is not in the begin state
    - After verifying the begin state, update fails because of wrong version (this should never actually happen since an RS only does this transition following a transition to the begin state. If two RS are conflicting, one would fail the original transition to the begin state and not this transition)
    Does not set any watches.
    This method should only be used by a RegionServer when merging two regions.
    Parameters:
    merged - region to be transitioned to opened
    a - merging region A
    b - merging region B
    serverName - server event originates from
    rmd - region merge details
    beginState - the expected current state the node should be
    endState - the state to be transition to
    
    Throws:
    
    IOException

Class ZkRegionMergeCoordination

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.coordination.RegionMergeCoordination

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

manager

watcher

LOG

Constructor Detail

ZkRegionMergeCoordination

Method Detail

getDefaultDetails

waitForRegionMergeTransaction

startRegionMergeTransaction

clean

completeRegionMergeTransaction

confirmRegionMergeTransaction

processRegionMergeRequest

transitionMergingNode