Package com.google.cloud.bigtable.grpc.async

Class ResourceLimiter

java.lang.Object

com.google.cloud.bigtable.grpc.async.ResourceLimiter

public class ResourceLimiter
extends Object

This class limits access by RPCs to system resources

Version:

$Id: $Id

Author:

sduskis

Constructor Summary

Constructors

Constructor	Description
ResourceLimiter(ResourceLimiterStats stats, long maxHeapSize, int maxInFlightRpcs)	Constructor for ResourceLimiter.

Method Summary

Modifier and Type	Method	Description
int	getAbsoluteMaxInFlightRpcs()	Getter for the field maxInFlightRpcs.
int	getCurrentInFlightMaxRpcs()	Getter for the field currentInFlightMaxRpcs.
long	getHeapSize()	getHeapSize.
long	getMaxHeapSize()	Getter for the field maxHeapSize.
boolean	hasInflightRequests()	hasInflightRequests.
boolean	isFull()	isFull.
void	markCanBeCompleted(long id)	Mark an operation id, as returned by registerOperationWithHeapSize, as complete
long	registerOperationWithHeapSize(long heapSize)	Register an operation with the given size before sending.
void	setCurrentInFlightMaxRpcs(int currentInFlightMaxRpcs)	Setter for the field currentInFlightMaxRpcs.
void	throttle(int bulkMutationRpcTargetMs)	Enable an experimental feature that will throttle requests made from BulkMutation.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceLimiter

public ResourceLimiter(ResourceLimiterStats stats,
                       long maxHeapSize,
                       int maxInFlightRpcs)

Constructor for ResourceLimiter.

Parameters:

maxHeapSize - a long.

maxInFlightRpcs - a int.

Method Detail

registerOperationWithHeapSize

public long registerOperationWithHeapSize(long heapSize)
                                   throws InterruptedException

Register an operation with the given size before sending. This call WILL BLOCK until resources are available. This method must be paired with a call to markCanBeCompleted in order to make sure resources are properly released.

Parameters:

heapSize - The serialized size of the RPC to be sent

Returns:

A unique operation id

Throws:

InterruptedException - if any.

markCanBeCompleted

public void markCanBeCompleted(long id)

Mark an operation id, as returned by registerOperationWithHeapSize, as complete

Parameters:

id - a long.

getMaxHeapSize

public long getMaxHeapSize()

Getter for the field maxHeapSize.

Returns:

The maximum allowed number of bytes across all across all outstanding RPCs

getAbsoluteMaxInFlightRpcs

public int getAbsoluteMaxInFlightRpcs()

Getter for the field maxInFlightRpcs.

Returns:

The maximum allowed number of in-flight RPCs

getCurrentInFlightMaxRpcs

public int getCurrentInFlightMaxRpcs()

Getter for the field currentInFlightMaxRpcs.

Returns:

The current maximum number of allowed in-flight RPCs

setCurrentInFlightMaxRpcs

public void setCurrentInFlightMaxRpcs(int currentInFlightMaxRpcs)

Setter for the field currentInFlightMaxRpcs.

getHeapSize

public long getHeapSize()

getHeapSize.

Returns:

The total size of all currently outstanding RPCs

isFull

public boolean isFull()

isFull.

Returns:

true if no more RPCs can be started, false otherwise

hasInflightRequests

public boolean hasInflightRequests()

hasInflightRequests.

Returns:

true if there are currently in-flight RPCs

throttle

public void throttle(int bulkMutationRpcTargetMs)

Enable an experimental feature that will throttle requests made from BulkMutation. The logic is as follows:

• To start:
  • reduce parallelism to 25% -- The parallelism is high to begin with. This reduction should reduce the impacts of a bursty job, such as those found in Dataflow.
• every 20 seconds:

     if (rpc_latency > threshold) {
        decrease parallelism by 10% of original maximum.
     } else if (rpc_latency < threshold && rpcsWereThrottled()) {
        increase parallelism by 5% of original maximum.
     }
   

  NOTE: increases are capped by the initial maximum. Decreases are floored at 1% of the original maximum so that there is some level of throughput.

Parameters:

bulkMutationRpcTargetMs - the target for latency of MutateRows requests in milliseconds.