org.apache.hadoop.hbase.client

Class ClientSmallScanner

java.lang.Object

org.apache.hadoop.hbase.client.AbstractClientScanner

org.apache.hadoop.hbase.client.ClientScanner

org.apache.hadoop.hbase.client.ClientSmallScanner

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<Result>, ResultScanner

@InterfaceAudience.Private
public class ClientSmallScanner
extends ClientScanner

Client scanner for small scan. Generally, only one RPC is called to fetch the scan results, unless the results cross multiple regions or the row count of results excess the caching. For small scan, it will get better performance than ClientScanner

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ClientSmallScanner.SmallScannerCallableFactory

Field Summary

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

cache, caching, callable, caller, closed, conf, currentRegion, lastNext, lastResult, maxScannerResultSize, partialResults, partialResultsRow, pool, primaryOperationTimeout, rpcControllerFactory, scan, scanMetricsPublished, scannerTimeout

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

scanMetrics

Constructor Summary

Constructors

Constructor and Description
ClientSmallScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName, ClusterConnection connection, RpcRetryingCallerFactory rpcFactory, RpcControllerFactory controllerFactory, ExecutorService pool, int primaryOperationTimeout) Create a new ShortClientScanner for the specified table.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes the scanner and releases any resources it has allocated
protected void	initializeScannerInConstruction()
protected void	loadCache() Contact the servers to load more Results in the cache.
Result	next() Grab the next row's worth of values.
protected void	setScannerCallableFactory(ClientSmallScanner.SmallScannerCallableFactory callableFactory)

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

checkScanStopRow, createClosestRowBefore, getCacheSize, getCaching, getConf, getConnection, getMaxResultSize, getPool, getPrimaryOperationTimeout, getResultsToAddToCache, getRetries, getScan, getScannerCallable, getScannerTimeout, getTable, getTableName, getTimestamp, nextScanner, renewLease, writeScanMetrics

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

getScanMetrics, initScanMetrics, iterator, next

Methods inherited from class java.lang.Object

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

Constructor Detail

ClientSmallScanner

public ClientSmallScanner(org.apache.hadoop.conf.Configuration conf,
                  Scan scan,
                  TableName tableName,
                  ClusterConnection connection,
                  RpcRetryingCallerFactory rpcFactory,
                  RpcControllerFactory controllerFactory,
                  ExecutorService pool,
                  int primaryOperationTimeout)
                   throws IOException

Create a new ShortClientScanner for the specified table. Take note that the passed Scan 's start row maybe changed changed.

Parameters:

conf - The Configuration to use.

scan - Scan to use in this scanner

tableName - The table that we wish to rangeGet

connection - Connection identifying the cluster

rpcFactory - Factory used to create the RpcRetryingCaller

controllerFactory - Factory used to access RPC payloads

pool - Threadpool for RPC threads

primaryOperationTimeout - Call timeout

Throws:

IOException - If the remote call fails

Method Detail

initializeScannerInConstruction

protected void initializeScannerInConstruction()
                                        throws IOException

Overrides:

initializeScannerInConstruction in class ClientScanner

Throws:

IOException

next

public Result next()
            throws IOException

Description copied from interface: ResultScanner

Grab the next row's worth of values. The scanner will return a Result.

Specified by:

next in interface ResultScanner

Overrides:

next in class ClientScanner

Returns:

Result object if there is another row, null if the scanner is exhausted.

Throws:

IOException - e

loadCache

protected void loadCache()
                  throws IOException

Description copied from class: ClientScanner

Contact the servers to load more Results in the cache.

Overrides:

loadCache in class ClientScanner

Throws:

IOException

close

public void close()

Description copied from interface: ResultScanner

Closes the scanner and releases any resources it has allocated

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ResultScanner

Overrides:

close in class ClientScanner

setScannerCallableFactory

protected void setScannerCallableFactory(ClientSmallScanner.SmallScannerCallableFactory callableFactory)