TakeSnapshotHandler (Apache HBase 1.4.11 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`
`protected HTableDescriptor`	`htd`
`protected MasterServices`	`master`
`protected MetricsSnapshot`	`metricsSnapshot`
`protected ForeignExceptionDispatcher`	`monitor`
`protected org.apache.hadoop.fs.Path`	`rootDir`
`protected org.apache.hadoop.fs.FileSystem`	`rootFs`
`protected org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription`	`snapshot`
`protected SnapshotManager`	`snapshotManager`
`protected SnapshotManifest`	`snapshotManifest`
`protected TableName`	`snapshotTable`
`protected MonitoredTask`	`status`
`protected TableLockManager.TableLock`	`tableLock`
`protected TableLockManager`	`tableLockManager`
`protected org.apache.hadoop.fs.Path`	`workingDir`
`protected org.apache.hadoop.fs.FileSystem`	`workingDirFs`

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, org.apache.hadoop.fs.FileSystem workingDirFs)` 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.
`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
  - 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
```
  - rootFs
```
protected final org.apache.hadoop.fs.FileSystem rootFs
```
  - workingDirFs
```
protected final org.apache.hadoop.fs.FileSystem workingDirFs
```
  - rootDir
```
protected final org.apache.hadoop.fs.Path rootDir
```
  - workingDir
```
protected final org.apache.hadoop.fs.Path workingDir
```
  - 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)
                    throws IOException
```
    Parameters:
    snapshot - descriptor of the snapshot to take
    masterServices - master services provider
    
    Throws:
    
    IllegalArgumentException - if the working snapshot directory set from the configuration is the same as the completed snapshot directory
    
    IOException - if the file system of the working snapshot directory cannot be determined
- Method Detail
  - 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,
                    org.apache.hadoop.fs.FileSystem workingDirFs)
                      throws SnapshotCreationException,
                             IOException
```
    Reset the manager to allow another snapshot to proceed. Commits the snapshot process by moving the working snapshot to the finalized filepath
    
    Parameters:
    snapshotDir - The file path of the completed snapshots
    workingDir - The file path of the in progress snapshots
    fs - The file system of the completed snapshots
    workingDirFs - The file system of the in progress snapshots
    
    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

master

metricsSnapshot

snapshot

conf

rootFs

workingDirFs

rootDir

workingDir

monitor

tableLockManager

tableLock

status

snapshotTable

snapshotManifest

snapshotManager

htd

Constructor Detail

TakeSnapshotHandler

Method Detail

prepare

process

releaseTableLock

completeSnapshot

snapshotRegions

snapshotDisabledRegion

cancel

isFinished

getCompletionTimestamp

getSnapshot

getExceptionIfFailed

rethrowExceptionIfFailed

rethrowException

hasException

getException