Package org.apache.hadoop.hbase.client

Class ReversedScannerCallable

java.lang.Object

org.apache.hadoop.hbase.client.RegionServerCallable<T,org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

org.apache.hadoop.hbase.client.ClientServiceCallable<Result[]>

org.apache.hadoop.hbase.client.ScannerCallable

org.apache.hadoop.hbase.client.ReversedScannerCallable

All Implemented Interfaces:

RetryingCallable<Result[]>

@Private
public class ReversedScannerCallable
extends ScannerCallable

A reversed ScannerCallable which supports backward scanning.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.client.ScannerCallable

ScannerCallable.MoreResults

Field Summary

Fields

Modifier and Type	Field	Description
private byte[]	locationSearchKey

Fields inherited from class org.apache.hadoop.hbase.client.ScannerCallable

closed, cursor, heartbeatMessage, id, instantiated, isRegionServerRemote, LOG, LOG_SCANNER_ACTIVITY, LOG_SCANNER_LATENCY_CUTOFF, renew, rpcControllerFactory, scan, scanMetrics, scannerId

Fields inherited from class org.apache.hadoop.hbase.client.RegionServerCallable

location, requestAttributes, rpcController, stub

Constructor Summary

Constructors

Constructor	Description
ReversedScannerCallable(ClusterConnection connection, TableName tableName, Scan scan, ScanMetrics scanMetrics, RpcControllerFactory rpcFactory, int replicaId, Map<String,byte[]> requestAttributes)

Method Summary

Modifier and Type	Method	Description
ScannerCallable	getScannerCallableForReplica(int id)
private Pair<HRegionLocation,byte[]>	locateLastRegionInRange(byte[] startKey, byte[] endKey)	Get the last region before the endkey, which will be used to execute the reverse scan
void	prepare(boolean reload)	Prepare by setting up any connections to servers, etc., ahead of call invocation.
void	throwable(Throwable t, boolean retrying)	Called when call throws an exception and we are going to retry; take action to make it so we succeed on next call (clear caches, do relookup of locations, etc.).

Methods inherited from class org.apache.hadoop.hbase.client.ScannerCallable

checkIfRegionServerIsRemote, getCaching, getCursor, getHRegionInfo, getLocationForReplica, getRegionLocationsForPrepare, getScan, isHeartbeatMessage, moreResultsForScan, moreResultsInRegion, rpcCall, setCaching, setClose, setMoreResultsForScan, setMoreResultsInRegion, setRenew

Methods inherited from class org.apache.hadoop.hbase.client.ClientServiceCallable

doGet, doMutate, setStubByServiceName

Methods inherited from class org.apache.hadoop.hbase.client.RegionServerCallable

call, getConnection, getExceptionMessageAdditionalDetail, getLocation, getPriority, getRow, getRpcController, getRpcControllerCellScanner, getStub, getTableName, setLocation, setRpcControllerCellScanner, setStub, sleep

Methods inherited from class java.lang.Object

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

Field Details

locationSearchKey

private byte[] locationSearchKey

Constructor Details

ReversedScannerCallable

public ReversedScannerCallable(ClusterConnection connection,
 TableName tableName,
 Scan scan,
 ScanMetrics scanMetrics,
 RpcControllerFactory rpcFactory,
 int replicaId,
 Map<String,byte[]> requestAttributes)

Parameters:

connection - which connection

tableName - table callable is on

scan - the scan to execute

scanMetrics - the ScanMetrics to used, if it is null, ScannerCallable won't collect metrics

rpcFactory - to create an RpcController to talk to the regionserver

replicaId - the replica id

Method Details

throwable

public void throwable(Throwable t,
 boolean retrying)

Description copied from interface: RetryingCallable

Called when call throws an exception and we are going to retry; take action to make it so we succeed on next call (clear caches, do relookup of locations, etc.).

Specified by:

throwable in interface RetryingCallable<Result[]>

Overrides:

throwable in class RegionServerCallable<Result[],org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ClientService.BlockingInterface>

Parameters:

t - throwable which was thrown

retrying - True if we are in retrying mode (we are not in retrying mode when max retries == 1; we ARE in retrying mode if retries > 1 even when we are the last attempt)

prepare

public void prepare(boolean reload)
             throws IOException

Description copied from interface: RetryingCallable

Prepare by setting up any connections to servers, etc., ahead of call invocation. TODO: We call prepare before EVERY call. Seems wrong. FIX!!!!

Specified by:

prepare in interface RetryingCallable<Result[]>

Overrides:

prepare in class ScannerCallable

Parameters:

reload - force reload of server location

Throws:

IOException - e

locateLastRegionInRange

private Pair<HRegionLocation,byte[]> locateLastRegionInRange(byte[] startKey,
 byte[] endKey)
                                                      throws IOException

Get the last region before the endkey, which will be used to execute the reverse scan

Parameters:

startKey - Starting row in range, inclusive

endKey - Ending row in range, exclusive

Returns:

The last location, and the rowKey used to find it. May be null, if a region could not be found.

Throws:

IOException

getScannerCallableForReplica

public ScannerCallable getScannerCallableForReplica(int id)

Overrides:

getScannerCallableForReplica in class ScannerCallable