fixed thread pools of fixed size, which create threads at startup, do not close them, and keep them all the time.
The cached cache thread pool is automatically deleted after one minute of idle time, and rebuilt when needed.
A limited scalable thread pool, but the number of threads in the pool will only grow and not shrink. (To avoid performance problems caused by sudden large traffic when shrinking).
fixed:
public class FixedThreadPool implements ThreadPool {
public Executor getExecutor(URL url) {
String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME);//Dubbo
int threads = url.getParameter(Constants.THREADS_KEY, Constants.DEFAULT_THREADS) ;//200
int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES);//0
return new ThreadPoolExecutor(threads, threads, 0, TimeUnit.MILLISECONDS,
queues == 0 ? new SynchronousQueue<Runnable>() :
(queues < 0 ? new LinkedBlockingQueue<Runnable>()
: new LinkedBlockingQueue<Runnable>(queues)),
new NamedThreadFactory(name, true), new AbortPolicyWithReport(name, url));
}
}
cached:
public class CachedThreadPool implements ThreadPool {
public Executor getExecutor(URL url) {
String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME);//Dubbo
int cores = url.getParameter(Constants.CORE_THREADS_KEY, Constants.DEFAULT_CORE_THREADS);//0
int threads = url.getParameter(Constants.THREADS_KEY, Integer.MAX_VALUE);//Integer.MAX_VALUE
int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES);//0
int alive = url.getParameter(Constants.ALIVE_KEY, Constants.DEFAULT_ALIVE);//60s
return new ThreadPoolExecutor(cores, threads, alive, TimeUnit.MILLISECONDS,
queues == 0 ? new SynchronousQueue<Runnable>() :
(queues < 0 ? new LinkedBlockingQueue<Runnable>()
: new LinkedBlockingQueue<Runnable>(queues)),
new NamedThreadFactory(name, true), new AbortPolicyWithReport(name, url));
}
}
limited:
public class LimitedThreadPool implements ThreadPool {
public Executor getExecutor(URL url) {
String name = url.getParameter(Constants.THREAD_NAME_KEY, Constants.DEFAULT_THREAD_NAME);//Dubbo
int cores = url.getParameter(Constants.CORE_THREADS_KEY, Constants.DEFAULT_CORE_THREADS);//0
int threads = url.getParameter(Constants.THREADS_KEY, Constants.DEFAULT_THREADS);//200
int queues = url.getParameter(Constants.QUEUES_KEY, Constants.DEFAULT_QUEUES);//0
return new ThreadPoolExecutor(cores, threads, Long.MAX_VALUE, TimeUnit.MILLISECONDS,
queues == 0 ? new SynchronousQueue<Runnable>() :
(queues < 0 ? new LinkedBlockingQueue<Runnable>()
: new LinkedBlockingQueue<Runnable>(queues)),
new NamedThreadFactory(name, true), new AbortPolicyWithReport(name, url));
}
}
provider端：默认是fixed
consumer端：默认是cached
默认线程大小是200
AbortPolicyWithReport:
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
String msg = String.format("Thread pool is EXHAUSTED!" +
" Thread Name: %s, Pool Size: %d (active: %d, core: %d, max: %d, largest: %d), Task: %d (completed: %d)," +
" Executor status:(isShutdown:%s, isTerminated:%s, isTerminating:%s), in %s://%s:%d!" ,
threadName, e.getPoolSize(), e.getActiveCount(), e.getCorePoolSize(), e.getMaximumPoolSize(), e.getLargestPoolSize(),
e.getTaskCount(), e.getCompletedTaskCount(), e.isShutdown(), e.isTerminated(), e.isTerminating(),
url.getProtocol(), url.getIp(), url.getPort());
logger .warn(msg);
throw new RejectedExecutionException(msg);
}
can be changed by:
<dubbo:protocol name="dubbo" dispatcher="all" threadpool="fixed" threads="100" />
<dubbo:provider threads ="200" threadpool="fixed"/>
The following error occurs when the threads in the thread are exhausted:
Solution:
1. Analyze through jstack -l pid to check the main lock resource contention, so as to carry out business code 2.
Increase the number of thread pools, the default is 200
3. Reduce the timeout time to avoid too long business processing time and exhaust all threads