Package org.apache.accumulo.core.spi.scan

Class SimpleScanDispatcher

java.lang.Object

org.apache.accumulo.core.spi.scan.SimpleScanDispatcher

All Implemented Interfaces:

ScanDispatcher

public class SimpleScanDispatcher
extends Object
implements ScanDispatcher

If no options are given, then this will default to an executor named default and ScanDispatch.CacheUsage.TABLE for index and data cache. This dispatcher supports the following options.

• table.scan.dispatcher.opts.executor=<scan executor name> : dispatches all scans to the named executor.
• table.scan.dispatcher.opts.multi_executor=<scan executor name> : dispatches batch scans to the named executor.
• table.scan.dispatcher.opts.single_executor=<scan executor name> : dispatches regular scans to the named executor.
• table.scan.dispatcher.opts.executor.<type>=<scan executor name> : dispatches scans that set the hint scan_type=<type> to the named executor. If this setting matches then it takes precedence over all other settings. See ScannerBase.setExecutionHints(Map)
• table.scan.dispatcher.opts.cacheUsage.<type>[.index|.data]=enabled|disabled|opportunistic|table : for scans that set the hint scan_type=<type> determines how the scan will use cache.

The multi_executor and single_executor options override the executor option.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.accumulo.core.spi.scan.ScanDispatcher

ScanDispatcher.DispatchParameters, ScanDispatcher.InitParameters

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_SCAN_EXECUTOR_NAME

Constructor Summary

Constructors

Constructor	Description
SimpleScanDispatcher()

Method Summary

Modifier and Type	Method	Description
ScanDispatch	dispatch(ScanDispatcher.DispatchParameters params)	Accumulo calls this method for each scan batch to determine what executor to use and how to utilize cache for the scan.
void	init(ScanDispatcher.InitParameters params)	This method is called once after a ScanDispatcher is instantiated.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_SCAN_EXECUTOR_NAME

public static final String DEFAULT_SCAN_EXECUTOR_NAME

See Also:

• Constant Field Values

Constructor Details

SimpleScanDispatcher

public SimpleScanDispatcher()

Method Details

init

public void init(ScanDispatcher.InitParameters params)

Description copied from interface: ScanDispatcher

This method is called once after a ScanDispatcher is instantiated.

Specified by:

init in interface ScanDispatcher

dispatch

public ScanDispatch dispatch(ScanDispatcher.DispatchParameters params)

Description copied from interface: ScanDispatcher

Accumulo calls this method for each scan batch to determine what executor to use and how to utilize cache for the scan.

Specified by:

dispatch in interface ScanDispatcher