org.apache.hadoop.hbase.coprocessor.example
Class ZooKeeperScanPolicyObserver

java.lang.Object
  org.apache.hadoop.hbase.coprocessor.BaseRegionObserver
      org.apache.hadoop.hbase.coprocessor.example.ZooKeeperScanPolicyObserver

All Implemented Interfaces:

Coprocessor, RegionObserver

public class ZooKeeperScanPolicyObserver
extends BaseRegionObserver

This is an example showing how a RegionObserver could configured via ZooKeeper in order to control a Region compaction, flush, and scan policy. This also demonstrated the use of shared RegionObserver state. See RegionCoprocessorEnvironment.getSharedData(). This would be useful for an incremental backup tool, which would indicate the last time of a successful backup via ZK and instruct HBase to not delete data that was inserted since (based on wall clock time). This implements org.apache.zookeeper.Watcher directly instead of using ZooKeeperWatcher, because RegionObservers come and go and currently listeners registered with ZooKeeperWatcher cannot be removed.

Nested Class Summary

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

Coprocessor.State

Field Summary

static String	node
static String	zkkey

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

PRIORITY_HIGHEST, PRIORITY_LOWEST, PRIORITY_SYSTEM, PRIORITY_USER, VERSION

Constructor Summary

ZooKeeperScanPolicyObserver()

Method Summary

protected ScanInfo	getScanInfo(Store store, RegionCoprocessorEnvironment e)
InternalScanner	preCompactScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c, Store store, List<? extends KeyValueScanner> scanners, ScanType scanType, long earliestPutTs, InternalScanner s)
InternalScanner	preFlushScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c, Store store, KeyValueScanner memstoreScanner, InternalScanner s)
KeyValueScanner	preStoreScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c, Store store, Scan scan, NavigableSet<byte[]> targetCols, KeyValueScanner s)
void	start(CoprocessorEnvironment e)
void	stop(CoprocessorEnvironment e)

Methods inherited from class org.apache.hadoop.hbase.coprocessor.BaseRegionObserver

postAppend, postBatchMutate, postBulkLoadHFile, postCheckAndDelete, postCheckAndPut, postClose, postCompact, postCompact, postCompactSelection, postCompactSelection, postCompleteSplit, postDelete, postExists, postFlush, postFlush, postGet, postGetClosestRowBefore, postGetOp, postIncrement, postIncrementColumnValue, postOpen, postPut, postRollBackSplit, postScannerClose, postScannerFilterRow, postScannerNext, postScannerOpen, postSplit, postWALRestore, preAppend, preBatchMutate, preBulkLoadHFile, preCheckAndDelete, preCheckAndPut, preClose, preCompact, preCompact, preCompactScannerOpen, preCompactSelection, preCompactSelection, preDelete, preExists, preFlush, preFlush, preGet, preGetClosestRowBefore, preGetOp, preIncrement, preIncrementColumnValue, preOpen, prePut, preRollBackSplit, preScannerClose, preScannerNext, preScannerOpen, preSplit, preSplit, preWALRestore

Methods inherited from class java.lang.Object

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

Field Detail

node

public static final String node

See Also:

Constant Field Values

zkkey

public static final String zkkey

See Also:

Constant Field Values

Constructor Detail

ZooKeeperScanPolicyObserver

public ZooKeeperScanPolicyObserver()

Method Detail

start

public void start(CoprocessorEnvironment e)
           throws IOException

Specified by:

start in interface Coprocessor

Overrides:

start in class BaseRegionObserver

Throws:

IOException

stop

public void stop(CoprocessorEnvironment e)
          throws IOException

Specified by:

stop in interface Coprocessor

Overrides:

stop in class BaseRegionObserver

Throws:

IOException

getScanInfo

protected ScanInfo getScanInfo(Store store,
                               RegionCoprocessorEnvironment e)

preFlushScannerOpen

public InternalScanner preFlushScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c,
                                           Store store,
                                           KeyValueScanner memstoreScanner,
                                           InternalScanner s)
                                    throws IOException

Specified by:

preFlushScannerOpen in interface RegionObserver

Overrides:

preFlushScannerOpen in class BaseRegionObserver

Throws:

IOException

preCompactScannerOpen

public InternalScanner preCompactScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c,
                                             Store store,
                                             List<? extends KeyValueScanner> scanners,
                                             ScanType scanType,
                                             long earliestPutTs,
                                             InternalScanner s)
                                      throws IOException

Specified by:

preCompactScannerOpen in interface RegionObserver

Overrides:

preCompactScannerOpen in class BaseRegionObserver

Throws:

IOException

preStoreScannerOpen

public KeyValueScanner preStoreScannerOpen(ObserverContext<RegionCoprocessorEnvironment> c,
                                           Store store,
                                           Scan scan,
                                           NavigableSet<byte[]> targetCols,
                                           KeyValueScanner s)
                                    throws IOException

Specified by:

preStoreScannerOpen in interface RegionObserver

Overrides:

preStoreScannerOpen in class BaseRegionObserver

Throws:

IOException