software.amazon.kinesis.leases

Class LeaseStatsRecorder

java.lang.Object

software.amazon.kinesis.leases.LeaseStatsRecorder

@ThreadSafe
public class LeaseStatsRecorder
extends Object

This class records the stats for the leases. The stats are recorded in a thread safe queue, and the throughput is calculated by summing up the bytes and dividing by interval in seconds. This class is thread safe and backed by thread safe data structures.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LeaseStatsRecorder.LeaseStats

Field Summary

Fields

Modifier and Type	Field and Description
static int	BYTES_PER_KB

Constructor Summary

Constructors

Constructor and Description
LeaseStatsRecorder()

Method Summary

Modifier and Type	Method and Description
void	dropLeaseStats(String leaseKey) Clear the in-memory stats for the lease when a lease is reassigned (due to shut down or lease stealing)
Double	getThroughputKBps(String leaseKey) Calculates the throughput in KBps for the given leaseKey.
void	recordStats(@NonNull LeaseStatsRecorder.LeaseStats leaseStats) This method provides happens-before semantics (i.e., the action (access or removal) from a thread happens before the action from subsequent thread) for the stats recording in multithreaded environment.

Methods inherited from class java.lang.Object

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

Field Detail

BYTES_PER_KB

public static final int BYTES_PER_KB

See Also:

Constant Field Values

Constructor Detail

LeaseStatsRecorder

public LeaseStatsRecorder()

Method Detail

recordStats

public void recordStats(@NonNull
                        @NonNull LeaseStatsRecorder.LeaseStats leaseStats)

This method provides happens-before semantics (i.e., the action (access or removal) from a thread happens before the action from subsequent thread) for the stats recording in multithreaded environment.

getThroughputKBps

public Double getThroughputKBps(String leaseKey)

Calculates the throughput in KBps for the given leaseKey. Method first clears the items that are older than renewerFrequencyInMillis from the queue and then calculates the throughput per second during renewerFrequencyInMillis interval and then returns the ExponentialMovingAverage of the throughput. If method is called in quick succession with or without new stats the result can be different as ExponentialMovingAverage decays old values on every new call. This method is thread safe.

Parameters:

leaseKey - leaseKey for which stats are required

Returns:

throughput in Kbps, returns null if there is no stats available for the leaseKey.

dropLeaseStats

public void dropLeaseStats(String leaseKey)

Clear the in-memory stats for the lease when a lease is reassigned (due to shut down or lease stealing)

Parameters:

leaseKey - leaseKey, for which stats are supposed to be clear.