org.apache.cassandra.concurrent
Class DebuggableThreadPoolExecutor

java.lang.Object
  java.util.concurrent.AbstractExecutorService
      java.util.concurrent.ThreadPoolExecutor
          org.apache.cassandra.concurrent.DebuggableThreadPoolExecutor

All Implemented Interfaces:

java.util.concurrent.Executor, java.util.concurrent.ExecutorService

Direct Known Subclasses:

JMXEnabledThreadPoolExecutor

public class DebuggableThreadPoolExecutor
extends java.util.concurrent.ThreadPoolExecutor

This class encorporates some Executor best practices for Cassandra. Most of the executors in the system should use or extend this. There are two main improvements over a vanilla TPE: - If a task throws an exception, the default uncaught exception handler will be invoked; if there is no such handler, the exception will be logged. - MaximumPoolSize is not supported. Here is what that means (quoting TPE javadoc): If fewer than corePoolSize threads are running, the Executor always prefers adding a new thread rather than queuing. If corePoolSize or more threads are running, the Executor always prefers queuing a request rather than adding a new thread. If a request cannot be queued, a new thread is created unless this would exceed maximumPoolSize, in which case, the task will be rejected. We don't want this last stage of creating new threads if the queue is full; it makes it needlessly difficult to reason about the system's behavior. In other words, if DebuggableTPE has allocated our maximum number of (core) threads and the queue is full, we want the enqueuer to block. But to allow the number of threads to drop if a stage is less busy, core thread timeout is enabled.

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor

java.util.concurrent.ThreadPoolExecutor.AbortPolicy, java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy, java.util.concurrent.ThreadPoolExecutor.DiscardOldestPolicy, java.util.concurrent.ThreadPoolExecutor.DiscardPolicy

Field Summary

static java.util.concurrent.RejectedExecutionHandler	blockingExecutionHandler
protected static org.slf4j.Logger	logger

Constructor Summary

protected	DebuggableThreadPoolExecutor(int corePoolSize, int maxPoolSize, long keepAliveTime, java.util.concurrent.TimeUnit unit, java.util.concurrent.BlockingQueue<java.lang.Runnable> workQueue, java.util.concurrent.ThreadFactory threadFactory)
	DebuggableThreadPoolExecutor(int corePoolSize, long keepAliveTime, java.util.concurrent.TimeUnit unit, java.util.concurrent.BlockingQueue<java.lang.Runnable> queue, java.util.concurrent.ThreadFactory factory)
	DebuggableThreadPoolExecutor(java.lang.String threadPoolName, int priority)

Method Summary

void	afterExecute(java.lang.Runnable r, java.lang.Throwable t)
static DebuggableThreadPoolExecutor	createWithPoolSize(java.lang.String threadPoolName, int size)
static void	logExceptionsAfterExecute(java.lang.Runnable r, java.lang.Throwable t)
protected void	onFinalAccept(java.lang.Runnable task)
protected void	onFinalRejection(java.lang.Runnable task)
protected void	onInitialRejection(java.lang.Runnable task)

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, beforeExecute, execute, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, shutdownNow, terminated

Methods inherited from class java.util.concurrent.AbstractExecutorService

invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submit

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static org.slf4j.Logger logger

blockingExecutionHandler

public static final java.util.concurrent.RejectedExecutionHandler blockingExecutionHandler

Constructor Detail

DebuggableThreadPoolExecutor

public DebuggableThreadPoolExecutor(java.lang.String threadPoolName,
                                    int priority)

DebuggableThreadPoolExecutor

public DebuggableThreadPoolExecutor(int corePoolSize,
                                    long keepAliveTime,
                                    java.util.concurrent.TimeUnit unit,
                                    java.util.concurrent.BlockingQueue<java.lang.Runnable> queue,
                                    java.util.concurrent.ThreadFactory factory)

DebuggableThreadPoolExecutor

protected DebuggableThreadPoolExecutor(int corePoolSize,
                                       int maxPoolSize,
                                       long keepAliveTime,
                                       java.util.concurrent.TimeUnit unit,
                                       java.util.concurrent.BlockingQueue<java.lang.Runnable> workQueue,
                                       java.util.concurrent.ThreadFactory threadFactory)

Method Detail

createWithPoolSize

public static DebuggableThreadPoolExecutor createWithPoolSize(java.lang.String threadPoolName,
                                                              int size)

onInitialRejection

protected void onInitialRejection(java.lang.Runnable task)

onFinalAccept

protected void onFinalAccept(java.lang.Runnable task)

onFinalRejection

protected void onFinalRejection(java.lang.Runnable task)

afterExecute

public void afterExecute(java.lang.Runnable r,
                         java.lang.Throwable t)

Overrides:

afterExecute in class java.util.concurrent.ThreadPoolExecutor

logExceptionsAfterExecute

public static void logExceptionsAfterExecute(java.lang.Runnable r,
                                             java.lang.Throwable t)