org.apache.hadoop.hbase.client

类 ClientAsyncPrefetchScanner

java.lang.Object

org.apache.hadoop.hbase.client.AbstractClientScanner

org.apache.hadoop.hbase.client.ClientScanner

org.apache.hadoop.hbase.client.ClientSimpleScanner

org.apache.hadoop.hbase.client.ClientAsyncPrefetchScanner

所有已实现的接口:

Closeable, AutoCloseable, Iterable<Result>, ResultScanner

@InterfaceAudience.Private
public class ClientAsyncPrefetchScanner
extends ClientSimpleScanner

ClientAsyncPrefetchScanner implements async scanner behaviour. Specifically, the cache used by this scanner is a concurrent queue which allows both the producer (hbase client) and consumer (application) to access the queue in parallel. The number of rows returned in a prefetch is defined by the caching factor and the result size factor. This class allocates a buffer cache, whose size is a function of both factors. The prefetch is invoked when the cache is half­filled, instead of waiting for it to be empty. This is defined in the method prefetchCondition().

字段概要

从类继承的字段 org.apache.hadoop.hbase.client.ClientScanner

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

从类继承的字段 org.apache.hadoop.hbase.client.AbstractClientScanner

scanMetrics

构造器概要

构造器

构造器和说明
ClientAsyncPrefetchScanner(org.apache.hadoop.conf.Configuration configuration, Scan scan, TableName name, ClusterConnection connection, RpcRetryingCallerFactory rpcCallerFactory, RpcControllerFactory rpcControllerFactory, ExecutorService pool, int replicaCallTimeoutMicroSecondScan)

方法概要

限定符和类型	方法和说明
protected void	addEstimatedSize(long estimatedSize)
void	close() Closes the scanner and releases any resources it has allocated
protected void	initCache()
Result	next() Grab the next row's worth of values.

从类继承的方法 org.apache.hadoop.hbase.client.ClientSimpleScanner

createScannerCallable, setNewStartKey

从类继承的方法 org.apache.hadoop.hbase.client.ClientScanner

getCacheCount, getCacheSize, getCaching, getConf, getConnection, getMaxResultSize, getPool, getPrimaryOperationTimeout, getRetries, getScan, getScannerTimeout, getTable, getTimestamp, initSyncCache, loadCache, moveToNextRegion, nextWithSyncCache, renewLease, writeScanMetrics

从类继承的方法 org.apache.hadoop.hbase.client.AbstractClientScanner

getScanMetrics, initScanMetrics

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.apache.hadoop.hbase.client.ResultScanner

iterator, next

从接口继承的方法 java.lang.Iterable

forEach, spliterator

构造器详细资料

ClientAsyncPrefetchScanner

public ClientAsyncPrefetchScanner(org.apache.hadoop.conf.Configuration configuration,
                                  Scan scan,
                                  TableName name,
                                  ClusterConnection connection,
                                  RpcRetryingCallerFactory rpcCallerFactory,
                                  RpcControllerFactory rpcControllerFactory,
                                  ExecutorService pool,
                                  int replicaCallTimeoutMicroSecondScan)
                           throws IOException

抛出:

IOException

方法详细资料

initCache

protected void initCache()

覆盖:

initCache 在类中 ClientScanner

next

public Result next()
            throws IOException

从接口复制的说明: ResultScanner

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

指定者:

next 在接口中 ResultScanner

覆盖:

next 在类中 ClientScanner

返回:

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

抛出:

IOException - e

close

public void close()

从接口复制的说明: ResultScanner

Closes the scanner and releases any resources it has allocated

指定者:

close 在接口中 Closeable

指定者:

close 在接口中 AutoCloseable

指定者:

close 在接口中 ResultScanner

覆盖:

close 在类中 ClientScanner

addEstimatedSize

protected void addEstimatedSize(long estimatedSize)

覆盖:

addEstimatedSize 在类中 ClientScanner