TakeSnapshotHandler (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.executor.EventHandler
- - org.apache.hadoop.hbase.master.snapshot.TakeSnapshotHandler

All Implemented Interfaces:

Comparable<Runnable>, Runnable, ForeignExceptionSnare, SnapshotSentinel

Direct Known Subclasses:

DisabledTableSnapshotHandler, EnabledTableSnapshotHandler
```
@InterfaceAudience.Private
public abstract class TakeSnapshotHandler
extends EventHandler
implements SnapshotSentinel, ForeignExceptionSnare
```
A handler for taking snapshots from the master. This is not a subclass of TableEventHandler because using that would incur an extra hbase:meta scan. The snapshotRegions(List) call should get implemented for each snapshot flavor.

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
`protected org.apache.hadoop.conf.Configuration`	`conf`
`private boolean`	`finished`
`protected org.apache.hadoop.fs.FileSystem`	`fs`
`protected HTableDescriptor`	`htd`
`private static org.apache.commons.logging.Log`	`LOG`
`protected MasterServices`	`master`
`protected MetricsSnapshot`	`metricsSnapshot`
`protected ForeignExceptionDispatcher`	`monitor`
`protected org.apache.hadoop.fs.Path`	`rootDir`
`protected org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription`	`snapshot`
`private org.apache.hadoop.fs.Path`	`snapshotDir`
`protected SnapshotManager`	`snapshotManager`
`protected SnapshotManifest`	`snapshotManifest`
`protected TableName`	`snapshotTable`
`protected MonitoredTask`	`status`
`protected TableLockManager.TableLock`	`tableLock`
`protected TableLockManager`	`tableLockManager`
`private MasterSnapshotVerifier`	`verifier`
`protected org.apache.hadoop.fs.Path`	`workingDir`

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

Constructor Summary

Constructors
Constructor and Description
`TakeSnapshotHandler(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot, MasterServices masterServices, SnapshotManager snapshotManager)`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`cancel(String why)` Actively cancel a running snapshot.
`void`	`completeSnapshot(org.apache.hadoop.fs.Path snapshotDir, org.apache.hadoop.fs.Path workingDir, org.apache.hadoop.fs.FileSystem fs)` Reset the manager to allow another snapshot to proceed
`long`	`getCompletionTimestamp()`
`ForeignException`	`getException()` Get the value of the captured exception.
`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()`
`boolean`	`hasException()` Non-exceptional form of `ForeignExceptionSnare.rethrowException()`.
`boolean`	`isFinished()` Check to see if the snapshot is finished, where finished may be success or failure.
`private HTableDescriptor`	`loadTableDescriptor()`
`TakeSnapshotHandler`	`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`	`process()` Execute the core common portions of taking a snapshot.
`protected void`	`releaseTableLock()`
`void`	`rethrowException()` Rethrow an exception currently held by the `ForeignExceptionSnare`.
`void`	`rethrowExceptionIfFailed()` Rethrow the exception returned by `SnapshotSentinel.getExceptionIfFailed()`.
`protected void`	`snapshotDisabledRegion(HRegionInfo regionInfo)` Take a snapshot of the specified disabled region
`protected abstract void`	`snapshotRegions(List<Pair<HRegionInfo,ServerName>> regions)` Snapshot the specified regions

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
```
  - finished
```
private volatile boolean finished
```
  - master
```
protected final MasterServices master
```
  - metricsSnapshot
```
protected final MetricsSnapshot metricsSnapshot
```
  - snapshot
```
protected final org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot
```
  - conf
```
protected final org.apache.hadoop.conf.Configuration conf
```
  - fs
```
protected final org.apache.hadoop.fs.FileSystem fs
```
  - rootDir
```
protected final org.apache.hadoop.fs.Path rootDir
```
  - snapshotDir
```
private final org.apache.hadoop.fs.Path snapshotDir
```
  - workingDir
```
protected final org.apache.hadoop.fs.Path workingDir
```
  - verifier
```
private final MasterSnapshotVerifier verifier
```
  - monitor
```
protected final ForeignExceptionDispatcher monitor
```
  - tableLockManager
```
protected final TableLockManager tableLockManager
```
  - tableLock
```
protected final TableLockManager.TableLock tableLock
```
  - status
```
protected final MonitoredTask status
```
  - snapshotTable
```
protected final TableName snapshotTable
```
  - snapshotManifest
```
protected final SnapshotManifest snapshotManifest
```
  - snapshotManager
```
protected final SnapshotManager snapshotManager
```
  - htd
```
protected HTableDescriptor htd
```
- Constructor Detail
  - TakeSnapshotHandler
```
public TakeSnapshotHandler(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot,
                   MasterServices masterServices,
                   SnapshotManager snapshotManager)
```
    Parameters:
    snapshot - descriptor of the snapshot to take
    masterServices - master services provider
- Method Detail
  - loadTableDescriptor
```
private HTableDescriptor loadTableDescriptor()
                                      throws FileNotFoundException,
                                             IOException
```
    Throws:
    
    FileNotFoundException
    
    IOException
  - prepare
```
public TakeSnapshotHandler prepare()
                            throws Exception
```
    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 EventHandler
    
    Returns:
    the instance of this class
    
    Throws:
    
    Exception - when something goes wrong
  - process
```
public void process()
```
    Execute the core common portions of taking a snapshot. The snapshotRegions(List) call should get implemented for each snapshot flavor.
    
    Specified by:
    
    process in class EventHandler
  - releaseTableLock
```
protected void releaseTableLock()
```
  - completeSnapshot
```
public void completeSnapshot(org.apache.hadoop.fs.Path snapshotDir,
                    org.apache.hadoop.fs.Path workingDir,
                    org.apache.hadoop.fs.FileSystem fs)
                      throws SnapshotCreationException,
                             IOException
```
    Reset the manager to allow another snapshot to proceed
    
    Parameters:
    snapshotDir - final path of the snapshot
    workingDir - directory where the in progress snapshot was built
    fs - FileSystem where the snapshot was built
    
    Throws:
    
    SnapshotCreationException - if the snapshot could not be moved
    
    IOException - the filesystem could not be reached
  - snapshotRegions
```
protected abstract void snapshotRegions(List<Pair<HRegionInfo,ServerName>> regions)
                                 throws IOException,
                                        org.apache.zookeeper.KeeperException
```
    Snapshot the specified regions
    
    Throws:
    
    IOException
    
    org.apache.zookeeper.KeeperException
  - snapshotDisabledRegion
```
protected void snapshotDisabledRegion(HRegionInfo regionInfo)
                               throws IOException
```
    Take a snapshot of the specified disabled region
    
    Throws:
    
    IOException
  - 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.
  - 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
  - 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
  - rethrowException
```
public void rethrowException()
                      throws ForeignException
```
    Description copied from interface: ForeignExceptionSnare
    
    Rethrow an exception currently held by the ForeignExceptionSnare. If there is no exception this is a no-op
    
    Specified by:
    
    rethrowException in interface ForeignExceptionSnare
    
    Throws:
    
    ForeignException - all exceptions from remote sources are procedure exceptions
  - hasException
```
public boolean hasException()
```
    Description copied from interface: ForeignExceptionSnare
    
    Non-exceptional form of ForeignExceptionSnare.rethrowException(). Checks to see if any process to which the exception checkers is bound has created an error that would cause a failure.
    
    Specified by:
    
    hasException in interface ForeignExceptionSnare
    
    Returns:
    true if there has been an error,false otherwise
  - getException
```
public ForeignException getException()
```
    Description copied from interface: ForeignExceptionSnare
    
    Get the value of the captured exception.
    
    Specified by:
    
    getException in interface ForeignExceptionSnare
    
    Returns:
    the captured foreign exception or null if no exception captured.

Class TakeSnapshotHandler

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.executor.EventHandler

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

LOG

finished

master

metricsSnapshot

snapshot

conf

fs

rootDir

snapshotDir

workingDir

verifier

monitor

tableLockManager

tableLock

status

snapshotTable

snapshotManifest

snapshotManager

htd

Constructor Detail

TakeSnapshotHandler

Method Detail

loadTableDescriptor

prepare

process

releaseTableLock

completeSnapshot

snapshotRegions

snapshotDisabledRegion

cancel

isFinished

getCompletionTimestamp

getSnapshot

getExceptionIfFailed

rethrowExceptionIfFailed

rethrowException

hasException

getException