Threads issues

[Eugene Prokopiev]

Hi,

I need to have some threads with AsyncHttpClient in each. My code looks like:

public class HttpClientApp {
   
    ExecutorService pool = Executors.newFixedThreadPool(25);
   
    public HttpClientApp() throws Exception {
        List<Future<String>> futures = new ArrayList<Future<String>>();
        for (int i=0;i<25;i++) {
            futures.add(pool.submit(new Callable<String>() {
                public String call() throws Exception {
                    try (AsyncHttpClient client = new AsyncHttpClient()) {
                        Future<Response> response = client.prepareGet("http://10.7.1.13:3000").execute();
                        return response.get().getStatusText();
                    }
                }
            }));
        }
        for (Future<String> future : futures)
            System.out.println(future.get());
        System.out.println("END");
    }
   
    public static void main(String[] args) throws Exception {
        new HttpClientApp();       
    }

}

On running it I see:

9:29:05 PM org.jboss.netty.channel.socket.nio.AbstractNioSelector
WARNING: Unexpected exception in the selector loop.
java.lang.OutOfMemoryError: unable to create new native thread
        at java.lang.Thread.start0(Native Method)
        at java.lang.Thread.start(Thread.java:714)
        at org.jboss.netty.util.HashedWheelTimer.start(HashedWheelTimer.java:273)
        at org.jboss.netty.util.HashedWheelTimer.newTimeout(HashedWheelTimer.java:337)
        at org.jboss.netty.channel.socket.nio.NioClientBoss$RegisterTask.run(NioClientBoss.java:185)
        at org.jboss.netty.channel.socket.nio.AbstractNioSelector.processTaskQueue(AbstractNioSelector.java:391)
        at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:315)
        at org.jboss.netty.channel.socket.nio.NioClientBoss.run(NioClientBoss.java:42)
        at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
        at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

^CJava HotSpot(TM) 64-Bit Server VM warning: Exception java.lang.OutOfMemoryError occurred dispatching signal SIGINT to handler- the VM may need to be forcibly terminated

or:

9:38:23 PM org.glassfish.grizzly.nio.SelectorRunner doSelect
SEVERE: doSelect exception
java.lang.OutOfMemoryError: unable to create new native thread
        at java.lang.Thread.start0(Native Method)
        at java.lang.Thread.start(Thread.java:714)
        at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:950)
        at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1368)
        at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.executeIoEvent(WorkerThreadIOStrategy.java:100)
        at org.glassfish.grizzly.strategies.AbstractIOStrategy.executeIoEvent(AbstractIOStrategy.java:89)
        at org.glassfish.grizzly.nio.SelectorRunner.iterateKeyEvents(SelectorRunner.java:414)
        at org.glassfish.grizzly.nio.SelectorRunner.iterateKeys(SelectorRunner.java:383)
        at org.glassfish.grizzly.nio.SelectorRunner.doSelect(SelectorRunner.java:347)
        at org.glassfish.grizzly.nio.SelectorRunner.run(SelectorRunner.java:278)
        at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
        at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
        at java.lang.Thread.run(Thread.java:745)

^CJava HotSpot(TM) 64-Bit Server VM warning: Exception java.lang.OutOfMemoryError occurred dispatching signal SIGINT to handler- the VM may need to be forcibly terminated

So, I have such problems with NettyAsyncHttpProvider and GrizlyAsyncHttpProvider and no problems with JDKAsyncHttpProvider. Why can it be and how to use NIO instead of threads with NettyAsyncHttpProvider and GrizlyAsyncHttpProvider?

[Excilys]

This is very wrong. You should be creating one single client instance, not one per thread!

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[Eugene Prokopiev]

This is very wrong. You should be creating one single client instance, not one per thread!

Thanks! What about selecting threads/nio model? Is it possible to configure?

[Bongjae Chang]

Hi Eugene,

I think you can use AsyncHttpClientConfig#Builder interface. Here is an example:

---

final AsyncHttpClientConfig.Builder configBuilder = new AsyncHttpClientConfig.Builder();

configBuilder.setExecutorService(yourThreadPoolExecutor);

final AsyncHttpClientConfig config = configBuilder.build();

final AsyncHttpClient asyncHttpClient = new AsyncHttpClient(new GrizzlyAsyncHttpProvider(config), config);

---

Then, the AHC will use your fixed thread pool with workers.

And rarely, I think you can also choose a NIO model with customizing your provider configuration such as using TransportCustomizer interface of Grizzly provider. (https://grizzly.java.net/iostrategies.html)

Thanks.

Regards,

Bongjae Chang

[Eugene Prokopiev]

Thanks!


--
WBR,
Eugene Prokopiev