org.apache.hadoop.hbase.quotas

Class FixedIntervalRateLimiter

java.lang.Object

org.apache.hadoop.hbase.quotas.RateLimiter

org.apache.hadoop.hbase.quotas.FixedIntervalRateLimiter

@InterfaceAudience.Private
 @InterfaceStability.Evolving
public class FixedIntervalRateLimiter
extends RateLimiter

With this limiter resources will be refilled only after a fixed interval of time.

Field Summary

Fields

Modifier and Type	Field and Description
static String	RATE_LIMITER_REFILL_INTERVAL_MS The FixedIntervalRateLimiter can be harsh from a latency/backoff perspective, which makes it difficult to fully and consistently utilize a quota allowance.

Fields inherited from class org.apache.hadoop.hbase.quotas.RateLimiter

DEFAULT_TIME_UNIT, QUOTA_RATE_LIMITER_CONF_KEY

Constructor Summary

Constructors

Constructor and Description
FixedIntervalRateLimiter()
FixedIntervalRateLimiter(long refillInterval)

Method Summary

Modifier and Type	Method and Description
long	getNextRefillTime()
long	getWaitInterval(long limit, long available, long amount) Time in milliseconds to wait for before requesting to consume 'amount' resource.
long	refill(long limit) Refill the available units w.r.t the elapsed time.
void	setNextRefillTime(long nextRefillTime)

Methods inherited from class org.apache.hadoop.hbase.quotas.RateLimiter

consume, consume, getAvailable, getLimit, getTimeUnitInMillis, getWaitIntervalMs, getWaitIntervalMs, isAvailable, isBypass, set, toString, update, waitInterval, waitInterval

Methods inherited from class java.lang.Object

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

Field Detail

RATE_LIMITER_REFILL_INTERVAL_MS

public static final String RATE_LIMITER_REFILL_INTERVAL_MS

The FixedIntervalRateLimiter can be harsh from a latency/backoff perspective, which makes it difficult to fully and consistently utilize a quota allowance. By configuring the RATE_LIMITER_REFILL_INTERVAL_MS to a lower value you will encourage the rate limiter to throw smaller wait intervals for requests which may be fulfilled in timeframes shorter than the quota's full interval. For example, if you're saturating a 100MB/sec read IO quota with a ton of tiny gets, then configuring this to a value like 100ms will ensure that your retry backoffs approach ~100ms, rather than 1sec. Be careful not to configure this too low, or you may produce a dangerous amount of retry volume.

See Also:

Constant Field Values

Constructor Detail

FixedIntervalRateLimiter

public FixedIntervalRateLimiter()

FixedIntervalRateLimiter

public FixedIntervalRateLimiter(long refillInterval)

Method Detail

refill

public long refill(long limit)

Description copied from class: RateLimiter

Refill the available units w.r.t the elapsed time.

Parameters:

limit - Maximum available resource units that can be refilled to.

Returns:

how many resource units may be refilled ?

getWaitInterval

public long getWaitInterval(long limit,
                            long available,
                            long amount)

Description copied from class: RateLimiter

Time in milliseconds to wait for before requesting to consume 'amount' resource.

Parameters:

limit - Maximum available resource units that can be refilled to.

available - Currently available resource units

amount - Resources for which time interval to calculate for

Returns:

estimate of the ms required to wait before being able to provide 'amount' resources.

setNextRefillTime

public void setNextRefillTime(long nextRefillTime)

Specified by:

setNextRefillTime in class RateLimiter

getNextRefillTime

public long getNextRefillTime()

Specified by:

getNextRefillTime in class RateLimiter