org.apache.hadoop.hbase.regionserver

Class ReversedMobStoreScanner

java.lang.Object

org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner

org.apache.hadoop.hbase.regionserver.NonReversedNonLazyKeyValueScanner

org.apache.hadoop.hbase.regionserver.StoreScanner

org.apache.hadoop.hbase.regionserver.ReversedStoreScanner

org.apache.hadoop.hbase.regionserver.ReversedMobStoreScanner

All Implemented Interfaces:

Closeable, AutoCloseable, ChangedReadersObserver, InternalScanner, KeyValueScanner, Shipper

@InterfaceAudience.Private
public class ReversedMobStoreScanner
extends ReversedStoreScanner

ReversedMobStoreScanner extends from ReversedStoreScanner, and is used to support reversed scanning in both the memstore and the MOB store.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	cacheMobBlocks
protected HMobStore	mobStore
private boolean	rawMobScan
private boolean	readEmptyValueOnMobCellMiss

Fields inherited from class org.apache.hadoop.hbase.regionserver.StoreScanner

currentScanners, DEFAULT_HBASE_CELLS_SCANNED_PER_HEARTBEAT_CHECK, HBASE_CELLS_SCANNED_PER_HEARTBEAT_CHECK, heap, LAZY_SEEK_ENABLED_BY_DEFAULT, readPt, store, STORESCANNER_PARALLEL_SEEK_ENABLE, STORESCANNER_PREAD_MAX_BYTES

Fields inherited from interface org.apache.hadoop.hbase.regionserver.KeyValueScanner

NO_NEXT_INDEXED_KEY

Constructor Summary

Constructors

Constructor and Description
ReversedMobStoreScanner(HStore store, ScanInfo scanInfo, Scan scan, NavigableSet<byte[]> columns, long readPt)

Method Summary

Modifier and Type	Method and Description
boolean	next(List<Cell> outResult, ScannerContext ctx) Firstly reads the cells from the HBase.

Methods inherited from class org.apache.hadoop.hbase.regionserver.ReversedStoreScanner

backwardSeek, checkScanOrder, newKVHeap, reseek, seek, seekAsDirection, seekScanners, seekToNextRow, seekToPreviousRow

Methods inherited from class org.apache.hadoop.hbase.regionserver.StoreScanner

checkFlushed, close, enableLazySeekGlobally, getAllScannersForTesting, getEstimatedNumberOfKvsScanned, getNextIndexedKey, getReadPoint, isScanUsePread, next, peek, reopenAfterFlush, resetKVHeap, selectScannersFrom, shipped, trySkipToNextColumn, trySkipToNextRow, trySwitchToStreamRead, updateReaders

Methods inherited from class org.apache.hadoop.hbase.regionserver.NonReversedNonLazyKeyValueScanner

seekToLastRow

Methods inherited from class org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner

doRealSeek, enforceSeek, getFilePath, isFileScanner, realSeekDone, requestSeek, shouldUseScanner

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.regionserver.KeyValueScanner

close, enforceSeek, getFilePath, getNextIndexedKey, getScannerOrder, isFileScanner, next, peek, realSeekDone, requestSeek, seekToLastRow, shouldUseScanner

Methods inherited from interface org.apache.hadoop.hbase.regionserver.Shipper

shipped

Methods inherited from interface org.apache.hadoop.hbase.regionserver.InternalScanner

next

Field Detail

cacheMobBlocks

private boolean cacheMobBlocks

rawMobScan

private boolean rawMobScan

readEmptyValueOnMobCellMiss

private boolean readEmptyValueOnMobCellMiss

mobStore

protected final HMobStore mobStore

Constructor Detail

ReversedMobStoreScanner

ReversedMobStoreScanner(HStore store,
                        ScanInfo scanInfo,
                        Scan scan,
                        NavigableSet<byte[]> columns,
                        long readPt)
                 throws IOException

Throws:

IOException

Method Detail

next

public boolean next(List<Cell> outResult,
                    ScannerContext ctx)
             throws IOException

Firstly reads the cells from the HBase. If the cell is a reference cell (which has the reference tag), the scanner need seek this cell from the mob file, and use the cell found from the mob file as the result.

Specified by:

next in interface InternalScanner

Overrides:

next in class StoreScanner

Parameters:

outResult - return output array

Returns:

true if there are more rows, false if scanner is done

Throws:

IOException - e