org.apache.hadoop.hbase.client

Class AsyncClientSmallReversedScanner

java.lang.Object

org.apache.hadoop.hbase.client.AsyncClientScanner

org.apache.hadoop.hbase.client.AsyncReversedClientScanner

org.apache.hadoop.hbase.client.AsyncClientSmallReversedScanner

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, AsyncResultScanner

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class AsyncClientSmallReversedScanner
extends AsyncReversedClientScanner

Client scanner for small reversed scan. Generally, only one RPC is called to fetch the scan results, unless the results cross multiple regions or the row count of results exceed the caching.

For small scan, it will get better performance than ReversedClientScanner

Field Summary

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

caching, callable, caller, closed, currentRegion, lastNext, lastResult, maxScannerResultSize, scan, scanMetrics, scanMetricsPublished, scannerTimeout

Constructor Summary

Constructors

Constructor and Description
AsyncClientSmallReversedScanner(AsyncRpcClient client, org.apache.hadoop.hbase.client.Scan scan, org.apache.hadoop.hbase.TableName tableName) Create a new ReversibleClientScanner for the specified table Note that the passed Scan's start row maybe changed.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
<H extends ResponseHandler<org.apache.hadoop.hbase.client.Result[]>> H	nextBatch(H handler) Get the default number of rows as set by "hbase.client.scanner.caching"

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

checkScanStopRow, createClosestRowBefore, getScannerCallable, nextScanner

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

getScan, getScanMetrics, getScannerCallable, getTable, getTimestamp, initScanMetrics, isScanDone, setScanDone, writeScanMetrics

Methods inherited from class java.lang.Object

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

Constructor Detail

AsyncClientSmallReversedScanner

public AsyncClientSmallReversedScanner(AsyncRpcClient client,
                               org.apache.hadoop.hbase.client.Scan scan,
                               org.apache.hadoop.hbase.TableName tableName)

Create a new ReversibleClientScanner for the specified table Note that the passed Scan's start row maybe changed.

Parameters:

client - The AsyncRpcClient to use.

scan - Scan to use in this scanner

tableName - The table that we wish to scan

Method Detail

nextBatch

public <H extends ResponseHandler<org.apache.hadoop.hbase.client.Result[]>> H nextBatch(H handler)

Description copied from interface: AsyncResultScanner

Get the default number of rows as set by "hbase.client.scanner.caching"

Specified by:

nextBatch in interface AsyncResultScanner

Overrides:

nextBatch in class AsyncClientScanner

Parameters:

handler - to handle responses

Returns:

Between zero and nbRows Results

close

public void close()

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class AsyncClientScanner