org.apache.accumulo.server.tabletserver

Class LargestFirstMemoryManager

java.lang.Object

org.apache.accumulo.server.tabletserver.LargestFirstMemoryManager

All Implemented Interfaces:

MemoryManager

public class LargestFirstMemoryManager
extends Object
implements MemoryManager

The LargestFirstMemoryManager attempts to keep memory between 80% and 90% full. It adapts over time the point at which it should start a compaction based on how full memory gets between successive calls. It will also flush idle tablets based on a per-table configurable idle time. It will only attempt to flush tablets up to 20% of all memory. And, as the name of the class would suggest, it flushes the tablet with the highest memory footprint. However, it actually chooses the tablet as a function of its size doubled for every 15 minutes of idle time.

Constructor Summary

Constructors

Constructor and Description
LargestFirstMemoryManager()

Method Summary

Methods

Modifier and Type	Method and Description
protected long	currentTimeMillis()
MemoryManagementActions	getMemoryManagementActions(List<TabletState> tablets) An implementation of this function will be called periodically by accumulo and should return a list of tablets to minor compact.
protected long	getMinCIdleThreshold(KeyExtent extent)
void	init(ServerConfiguration conf) Initialize the memory manager.
void	tabletClosed(KeyExtent extent) This method is called when a tablet is closed.

Methods inherited from class java.lang.Object

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

Constructor Detail

LargestFirstMemoryManager

public LargestFirstMemoryManager()

Method Detail

init

public void init(ServerConfiguration conf)

Description copied from interface: MemoryManager

Initialize the memory manager.

Specified by:

init in interface MemoryManager

getMinCIdleThreshold

protected long getMinCIdleThreshold(KeyExtent extent)

getMemoryManagementActions

public MemoryManagementActions getMemoryManagementActions(List<TabletState> tablets)

Description copied from interface: MemoryManager

An implementation of this function will be called periodically by accumulo and should return a list of tablets to minor compact. Instructing a tablet that is already minor compacting (this can be inferred from the TabletState) to minor compact has no effect. Holding all ingest does not affect metadata tablets.

Specified by:

getMemoryManagementActions in interface MemoryManager

currentTimeMillis

protected long currentTimeMillis()

tabletClosed

public void tabletClosed(KeyExtent extent)

Description copied from interface: MemoryManager

This method is called when a tablet is closed. A memory manger can clean up any per tablet state it is keeping when this is called.

Specified by:

tabletClosed in interface MemoryManager