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, Iterable<Result>, ResultScanner

@InterfaceAudience.Public
@InterfaceStability.Evolving
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

protected static class

ClientSmallScanner.SmallScannerCallableFactory

Field Summary

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

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

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

scanMetrics

Constructor Summary

ClientSmallScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName)
Create a new ClientSmallScanner for the specified table.

ClientSmallScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName, HConnection connection)
Create a new ClientSmallScanner for the specified table.

ClientSmallScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName, HConnection connection, RpcRetryingCallerFactory rpcFactory, RpcControllerFactory controllerFactory)
Create a new ShortClientScanner for the specified table Note that the passed Scan's start row maybe changed changed.

Method Summary

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	setRpcControllerFactory(RpcControllerFactory rpcControllerFactory)
protected void	setRpcRetryingCaller(RpcRetryingCaller<Result[]> caller)
protected void	setScannerCallableFactory(ClientSmallScanner.SmallScannerCallableFactory callableFactory)

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

checkScanStopRow, getCacheSize, getConnection, getMaxResultSize, getScan, getScannerCallable, 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)
                   throws IOException

Create a new ClientSmallScanner for the specified table. An HConnection will be retrieved using the passed Configuration. Note that the passed Scan 's start row maybe changed.

Parameters:

conf - The Configuration to use.

scan - Scan to use in this scanner

tableName - The table that we wish to rangeGet

Throws:

IOException

ClientSmallScanner

public ClientSmallScanner(org.apache.hadoop.conf.Configuration conf,
                          Scan scan,
                          TableName tableName,
                          HConnection connection)
                   throws IOException

Create a new ClientSmallScanner for the specified table. An HConnection will be retrieved using the passed Configuration. Note that the passed Scan 's start row maybe changed.

Parameters:

conf -

scan -

tableName -

connection -

Throws:

IOException

ClientSmallScanner

public ClientSmallScanner(org.apache.hadoop.conf.Configuration conf,
                          Scan scan,
                          TableName tableName,
                          HConnection connection,
                          RpcRetryingCallerFactory rpcFactory,
                          RpcControllerFactory controllerFactory)
                   throws IOException

Create a new ShortClientScanner for the specified table 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 -

controllerFactory -

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 ResultScanner

Overrides:

close in class ClientScanner

setScannerCallableFactory

protected void setScannerCallableFactory(ClientSmallScanner.SmallScannerCallableFactory callableFactory)

setRpcRetryingCaller

protected void setRpcRetryingCaller(RpcRetryingCaller<Result[]> caller)

setRpcControllerFactory

protected void setRpcControllerFactory(RpcControllerFactory rpcControllerFactory)