RestoreSnapshotHandler (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.executor.EventHandler
- - org.apache.hadoop.hbase.master.handler.TableEventHandler
  - - org.apache.hadoop.hbase.master.snapshot.RestoreSnapshotHandler

All Implemented Interfaces:

Comparable<Runnable>, Runnable, SnapshotSentinel
```
@InterfaceAudience.Private
public class RestoreSnapshotHandler
extends TableEventHandler
implements SnapshotSentinel
```
Handler to Restore a snapshot.
Uses RestoreSnapshotHelper to replace the table content with the data available in the snapshot.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.hadoop.hbase.executor.EventHandler
  EventHandler.EventHandlerListener

Field Summary

Fields
Modifier and Type	Field and Description
`private HTableDescriptor`	`hTableDescriptor`
`private static org.apache.commons.logging.Log`	`LOG`
`private MetricsSnapshot`	`metricsSnapshot`
`private ForeignExceptionDispatcher`	`monitor`
`private org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription`	`snapshot`
`private MonitoredTask`	`status`
`private boolean`	`stopped`

Fields inherited from class org.apache.hadoop.hbase.master.handler.TableEventHandler
masterServices, tableLock, tableName

Fields inherited from class org.apache.hadoop.hbase.executor.EventHandler
eventType, seqids, server, waitingTimeForEvents

Constructor Summary

Constructors
Constructor and Description
`RestoreSnapshotHandler(MasterServices masterServices, org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot, HTableDescriptor htd)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`cancel(String why)` Actively cancel a running snapshot.
`protected void`	`completed(Throwable exception)` Called after that process() is completed.
`private void`	`forceRegionsOffline(List<HRegionInfo> hris)`
`private void`	`forceRegionsOffline(RestoreSnapshotHelper.RestoreMetaChanges metaChanges)`
`long`	`getCompletionTimestamp()`
`ForeignException`	`getExceptionIfFailed()` Get the exception that caused the snapshot to fail, if the snapshot has failed.
`org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription`	`getSnapshot()`
`protected void`	`handleTableOperation(List<HRegionInfo> hris)` The restore table is executed in place.
`boolean`	`isFinished()` Check to see if the snapshot is finished, where finished may be success or failure.
`RestoreSnapshotHandler`	`prepare()` Event handlers should do all the necessary checks in this method (rather than in the constructor, or in process()) so that the caller, which is mostly executed in the ipc context can fail fast.
`void`	`rethrowExceptionIfFailed()` Rethrow the exception returned by `SnapshotSentinel.getExceptionIfFailed()`.

Methods inherited from class org.apache.hadoop.hbase.master.handler.TableEventHandler
getTableDescriptor, prepareWithTableLock, process, releaseTableLock, reOpenAllRegions

Methods inherited from class org.apache.hadoop.hbase.executor.EventHandler
compareTo, getEventType, getInformativeName, getListener, getPriority, getSeqid, handleException, run, setListener, toString

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

- Field Detail
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
  - hTableDescriptor
```
private final HTableDescriptor hTableDescriptor
```
  - snapshot
```
private final org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot
```
  - monitor
```
private final ForeignExceptionDispatcher monitor
```
  - metricsSnapshot
```
private final MetricsSnapshot metricsSnapshot
```
  - status
```
private final MonitoredTask status
```
  - stopped
```
private volatile boolean stopped
```
- Constructor Detail
  - RestoreSnapshotHandler
```
public RestoreSnapshotHandler(MasterServices masterServices,
                      org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot,
                      HTableDescriptor htd)
                       throws IOException
```
    Throws:
    
    IOException
- Method Detail
  - prepare
```
public RestoreSnapshotHandler prepare()
                               throws IOException
```
    Description copied from class: EventHandler
    
    Event handlers should do all the necessary checks in this method (rather than in the constructor, or in process()) so that the caller, which is mostly executed in the ipc context can fail fast. Process is executed async from the client ipc, so this method gives a quick chance to do some basic checks. Should be called after constructing the EventHandler, and before process().
    
    Overrides:
    
    prepare in class TableEventHandler
    
    Returns:
    the instance of this class
    
    Throws:
    
    IOException
  - handleTableOperation
```
protected void handleTableOperation(List<HRegionInfo> hris)
                             throws IOException
```
    The restore table is executed in place. - The on-disk data will be restored - reference files are put in place without moving data - [if something fail here: you need to delete the table and re-run the restore] - hbase:meta will be updated - [if something fail here: you need to run hbck to fix hbase:meta entries] The passed in list gets changed in this method
    
    Specified by:
    
    handleTableOperation in class TableEventHandler
    
    Throws:
    
    IOException
  - forceRegionsOffline
```
private void forceRegionsOffline(RestoreSnapshotHelper.RestoreMetaChanges metaChanges)
```
  - forceRegionsOffline
```
private void forceRegionsOffline(List<HRegionInfo> hris)
```
  - completed
```
protected void completed(Throwable exception)
```
    Description copied from class: TableEventHandler
    
    Called after that process() is completed.
    
    Overrides:
    
    completed in class TableEventHandler
    
    Parameters:
    exception - null if process() is successful or not null if something has failed.
  - isFinished
```
public boolean isFinished()
```
    Description copied from interface: SnapshotSentinel
    
    Check to see if the snapshot is finished, where finished may be success or failure.
    
    Specified by:
    
    isFinished in interface SnapshotSentinel
    
    Returns:
    false if the snapshot is still in progress, true if the snapshot has finished
  - getCompletionTimestamp
```
public long getCompletionTimestamp()
```
    Specified by:
    
    getCompletionTimestamp in interface SnapshotSentinel
    
    Returns:
    -1 if the snapshot is in progress, otherwise the completion timestamp.
  - getSnapshot
```
public org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription getSnapshot()
```
    Specified by:
    
    getSnapshot in interface SnapshotSentinel
    
    Returns:
    the description of the snapshot being run
  - cancel
```
public void cancel(String why)
```
    Description copied from interface: SnapshotSentinel
    
    Actively cancel a running snapshot.
    
    Specified by:
    
    cancel in interface SnapshotSentinel
    
    Parameters:
    why - Reason for cancellation.
  - getExceptionIfFailed
```
public ForeignException getExceptionIfFailed()
```
    Description copied from interface: SnapshotSentinel
    
    Get the exception that caused the snapshot to fail, if the snapshot has failed.
    
    Specified by:
    
    getExceptionIfFailed in interface SnapshotSentinel
    
    Returns:
    ForeignException that caused the snapshot to fail, or null if the snapshot is still in progress or has succeeded
  - rethrowExceptionIfFailed
```
public void rethrowExceptionIfFailed()
                              throws ForeignException
```
    Description copied from interface: SnapshotSentinel
    
    Rethrow the exception returned by SnapshotSentinel.getExceptionIfFailed(). If there is no exception this is a no-op.
    
    Specified by:
    
    rethrowExceptionIfFailed in interface SnapshotSentinel
    
    Throws:
    
    ForeignException - all exceptions from remote sources are procedure exceptions

Class RestoreSnapshotHandler

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.executor.EventHandler

Field Summary

Fields inherited from class org.apache.hadoop.hbase.master.handler.TableEventHandler

Fields inherited from class org.apache.hadoop.hbase.executor.EventHandler

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.master.handler.TableEventHandler

Methods inherited from class org.apache.hadoop.hbase.executor.EventHandler

Methods inherited from class java.lang.Object

Field Detail

LOG

hTableDescriptor

snapshot

monitor

metricsSnapshot

status

stopped

Constructor Detail

RestoreSnapshotHandler

Method Detail

prepare

handleTableOperation

forceRegionsOffline

forceRegionsOffline

completed

isFinished

getCompletionTimestamp

getSnapshot

cancel

getExceptionIfFailed

rethrowExceptionIfFailed