Package org.apache.flink.runtime.taskmanager

Class MemoryLogger

java.lang.Object

java.lang.Thread

org.apache.flink.runtime.taskmanager.MemoryLogger

All Implemented Interfaces:

Runnable

public class MemoryLogger
extends Thread

A thread the periodically logs statistics about:

• Heap and non-heap memory usage
• Memory pools and pool usage
• Garbage collection times and counts

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor	Description
MemoryLogger(org.slf4j.Logger logger, long interval, CompletableFuture<Void> monitored)	Creates a new memory logger that logs in the given interval and lives until the given termination future completes.

Method Summary

Modifier and Type	Method	Description
static String	getDirectMemoryStatsAsString(BufferPoolMXBean bufferPoolMxBean)	Returns a String with the direct memory footprint.
static String	getGarbageCollectorStatsAsString(List<GarbageCollectorMXBean> gcMXBeans)	Gets the garbage collection statistics from the JVM.
static String	getMemoryPoolStatsAsString(List<MemoryPoolMXBean> poolBeans)	Gets the memory pool statistics from the JVM.
static String	getMemoryUsageStatsAsString(MemoryMXBean memoryMXBean)	Gets the memory footprint of the JVM in a string representation.
void	run()
void	shutdown()
static void	startIfConfigured(org.slf4j.Logger logger, org.apache.flink.configuration.Configuration configuration, CompletableFuture<Void> taskManagerTerminationFuture)

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Constructor Details

MemoryLogger

public MemoryLogger(org.slf4j.Logger logger,
 long interval,
 CompletableFuture<Void> monitored)

Creates a new memory logger that logs in the given interval and lives until the given termination future completes.

Parameters:

logger - The logger to use for outputting the memory statistics.

interval - The interval in which the thread logs.

monitored - termination future for the system to whose life the thread is bound. The thread terminates once the system terminates.

Method Details

startIfConfigured

public static void startIfConfigured(org.slf4j.Logger logger,
 org.apache.flink.configuration.Configuration configuration,
 CompletableFuture<Void> taskManagerTerminationFuture)

shutdown

public void shutdown()

run

public void run()

Specified by:

run in interface Runnable

Overrides:

run in class Thread

getMemoryUsageStatsAsString

public static String getMemoryUsageStatsAsString(MemoryMXBean memoryMXBean)

Gets the memory footprint of the JVM in a string representation.

Returns:

A string describing how much heap memory and direct memory are allocated and used.

getDirectMemoryStatsAsString

public static String getDirectMemoryStatsAsString(BufferPoolMXBean bufferPoolMxBean)

Returns a String with the direct memory footprint.

These stats are not part of the other memory beans.

Parameters:

bufferPoolMxBean - The direct buffer pool bean or null if none available.

Returns:

A string with the count, total capacity, and used direct memory.

getMemoryPoolStatsAsString

public static String getMemoryPoolStatsAsString(List<MemoryPoolMXBean> poolBeans)

Gets the memory pool statistics from the JVM.

Parameters:

poolBeans - The collection of memory pool beans.

Returns:

A string denoting the names and sizes of the memory pools.

getGarbageCollectorStatsAsString

public static String getGarbageCollectorStatsAsString(List<GarbageCollectorMXBean> gcMXBeans)

Gets the garbage collection statistics from the JVM.

Parameters:

gcMXBeans - The collection of garbage collector beans.

Returns:

A string denoting the number of times and total elapsed time in garbage collection.