Package org.apache.hadoop.hbase.coprocessor.example

Class ValueRewritingObserver

java.lang.Object

org.apache.hadoop.hbase.coprocessor.example.ValueRewritingObserver

All Implemented Interfaces:

Coprocessor, RegionCoprocessor, RegionObserver

@Private
public class ValueRewritingObserver
extends Object
implements RegionObserver, RegionCoprocessor

This RegionObserver replaces the values of Puts from one value to another on compaction.

Nested Class Summary

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

Coprocessor.State

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.coprocessor.RegionObserver

RegionObserver.MutationType

Field Summary

Fields

Modifier and Type	Field	Description
private CellBuilder	cellBuilder
private Bytes.ByteArrayComparator	comparator
static final String	ORIGINAL_VALUE_KEY
static final String	REPLACED_VALUE_KEY
private byte[]	replacedValue
private byte[]	sourceValue

Fields inherited from interface org.apache.hadoop.hbase.Coprocessor

PRIORITY_HIGHEST, PRIORITY_LOWEST, PRIORITY_SYSTEM, PRIORITY_USER, VERSION

Constructor Summary

Constructors

Constructor	Description
ValueRewritingObserver()

Method Summary

Modifier and Type	Method	Description
Optional<RegionObserver>	getRegionObserver()
InternalScanner	preCompact(ObserverContext<RegionCoprocessorEnvironment> c, Store store, InternalScanner scanner, ScanType scanType, CompactionLifeCycleTracker tracker, CompactionRequest request)	Called prior to writing the StoreFiles selected for compaction into a new StoreFile.
void	start(CoprocessorEnvironment env)	Called by the CoprocessorEnvironment during it's own startup to initialize the coprocessor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.hbase.Coprocessor

getServices, stop

Methods inherited from interface org.apache.hadoop.hbase.coprocessor.RegionCoprocessor

getBulkLoadObserver, getEndpointObserver

Methods inherited from interface org.apache.hadoop.hbase.coprocessor.RegionObserver

postAppend, postAppend, postAppendBeforeWAL, postBatchMutate, postBatchMutateIndispensably, postBulkLoadHFile, postCheckAndDelete, postCheckAndDelete, postCheckAndMutate, postCheckAndPut, postCheckAndPut, postClose, postCloseRegionOperation, postCommitStoreFile, postCompact, postCompactSelection, postDelete, postDelete, postExists, postFlush, postFlush, postGetOp, postIncrement, postIncrement, postIncrementBeforeWAL, postInstantiateDeleteTracker, postMemStoreCompaction, postMutationBeforeWAL, postOpen, postPut, postPut, postReplayWALs, postScannerClose, postScannerFilterRow, postScannerNext, postScannerOpen, postStartRegionOperation, postStoreFileReaderOpen, postWALRestore, preAppend, preAppend, preAppendAfterRowLock, preBatchMutate, preBulkLoadHFile, preCheckAndDelete, preCheckAndDelete, preCheckAndDeleteAfterRowLock, preCheckAndDeleteAfterRowLock, preCheckAndMutate, preCheckAndMutateAfterRowLock, preCheckAndPut, preCheckAndPut, preCheckAndPutAfterRowLock, preCheckAndPutAfterRowLock, preClose, preCommitStoreFile, preCompactScannerOpen, preCompactSelection, preDelete, preDelete, preExists, preFlush, preFlush, preFlushScannerOpen, preGetOp, preIncrement, preIncrement, preIncrementAfterRowLock, preMemStoreCompaction, preMemStoreCompactionCompact, preMemStoreCompactionCompactScannerOpen, preOpen, prePrepareTimeStampForDeleteVersion, prePut, prePut, preReplayWALs, preScannerClose, preScannerNext, preScannerOpen, preStoreFileReaderOpen, preStoreScannerOpen, preWALAppend, preWALRestore

Field Details

ORIGINAL_VALUE_KEY

public static final String ORIGINAL_VALUE_KEY

See Also:

• Constant Field Values

REPLACED_VALUE_KEY

public static final String REPLACED_VALUE_KEY

See Also:

• Constant Field Values

sourceValue

private byte[] sourceValue

replacedValue

private byte[] replacedValue

comparator

private Bytes.ByteArrayComparator comparator

cellBuilder

private CellBuilder cellBuilder

Constructor Details

ValueRewritingObserver

public ValueRewritingObserver()

Method Details

getRegionObserver

public Optional<RegionObserver> getRegionObserver()

Specified by:

getRegionObserver in interface RegionCoprocessor

start

public void start(CoprocessorEnvironment env)
           throws IOException

Description copied from interface: Coprocessor

Called by the CoprocessorEnvironment during it's own startup to initialize the coprocessor.

Specified by:

start in interface Coprocessor

Throws:

IOException

preCompact

public InternalScanner preCompact(ObserverContext<RegionCoprocessorEnvironment> c,
 Store store,
 InternalScanner scanner,
 ScanType scanType,
 CompactionLifeCycleTracker tracker,
 CompactionRequest request)

Description copied from interface: RegionObserver

Called prior to writing the StoreFiles selected for compaction into a new StoreFile.

To override or modify the compaction process, implementing classes can wrap the provided InternalScanner with a custom implementation that is returned from this method. The custom scanner can then inspect Cells from the wrapped scanner, applying its own policy to what gets written.

If implementations are wrapping the passed in InternalScanner, they can also have their implementation implement Shipper and delegate to the original scanner. This will cause compactions to free up memory as they progress, which is especially important for people using off-heap memory pools.

Keep in mind that when Shipper.shipped() is called, any cell references you maintain in your implementation may get corrupted. As such you should make sure to deep clone any cells that you need to keep reference to across invocations of shipped.

Specified by:

preCompact in interface RegionObserver

Parameters:

c - the environment provided by the region server

store - the store being compacted

scanner - the scanner over existing data used in the store file rewriting

scanType - type of Scan

tracker - tracker used to track the life cycle of a compaction

request - the requested compaction

Returns:

the scanner to use during compaction. Should not be null unless the implementation is writing new store files on its own.