Package org.apache.lucene.store

Class RateLimiter

java.lang.Object

org.apache.lucene.store.RateLimiter

Direct Known Subclasses:

MergeRateLimiter, RateLimiter.SimpleRateLimiter

public abstract class RateLimiter
extends Object

Abstract base class to rate limit IO. Typically implementations are shared across multiple IndexInputs or IndexOutputs (for example those involved all merging). Those IndexInputs and IndexOutputs would call pause(long) whenever the have read or written more than getMinPauseCheckBytes() bytes.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RateLimiter.SimpleRateLimiter	Simple class to rate limit IO.

Constructor Summary

Constructors

Constructor	Description
RateLimiter()

Method Summary

Modifier and Type	Method	Description
abstract double	getMBPerSec()	The current MB per second rate limit.
abstract long	getMinPauseCheckBytes()	How many bytes caller should add up itself before invoking pause(long).
abstract long	pause(long bytes)	Pauses, if necessary, to keep the instantaneous IO rate at or below the target.
abstract void	setMBPerSec(double mbPerSec)	Sets an updated MB per second rate limit.

Methods inherited from class java.lang.Object

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

Constructor Details

RateLimiter

public RateLimiter()

Method Details

setMBPerSec

public abstract void setMBPerSec(double mbPerSec)

Sets an updated MB per second rate limit. A subclass is allowed to perform dynamic updates of the rate limit during use.

getMBPerSec

public abstract double getMBPerSec()

The current MB per second rate limit.

pause

public abstract long pause(long bytes)
                    throws IOException

Pauses, if necessary, to keep the instantaneous IO rate at or below the target.

Note: the implementation is thread-safe

Returns:

the pause time in nano seconds

Throws:

IOException

getMinPauseCheckBytes

public abstract long getMinPauseCheckBytes()

How many bytes caller should add up itself before invoking pause(long). NOTE: The value returned by this method may change over time and is not guaranteed to be constant throughout the lifetime of the RateLimiter. Users are advised to refresh their local values with calls to this method to ensure consistency.