Prasad Wagle created ZEPPELIN-1084:
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Summary: Improving web performance by reducing number of broadcasts
Key: ZEPPELIN-1084
URL: https://issues.apache.org/jira/browse/ZEPPELIN-1084
Project: Zeppelin
Issue Type: Improvement
Reporter: Prasad Wagle
---------- Forwarded message ----------
From: Johnny W. <jzw.ser...@gmail.com>
Date: Tue, Jun 28, 2016 at 11:41 PM
Subject: Re: Improving web performance by reducing number of broadcasts
To: us...@zeppelin.apache.org, dev@zeppelin.apache.org
Thanks, Prasad! This is very helpful. The version we are using already includes
Jetty 9 & Zeppelin-820.
However, we still see web hangs quite frequently caused by broadcasting
updateNote. I may remove the synchronized block on noteSocketMap as a temporary
fix, but I am wondering whether there is a better solution.
+ zeppelin-dev, since this issue may significantly limit the scalability of
Zeppelin if there is a bad connection. One potential optimization can be:
instead of lock the whole map, use fine-grained lock on map entries.
Best,
Johnny
On Tue, Jun 28, 2016 at 4:34 AM, Prasad Wagle <prasadwa...@gmail.com> wrote:
Hi Johnny,
What version of the server are you using?
You may be interested in the following:
Email thread discussing zeppelin server hangs and reducing websocket connections
>From the thread: "I removed synchronized (noteSocketMap) from broadcast so
>that one bad
socket does not hang the server." This change helps with performance as well
and hasn't caused any problems. However, this is not a long-term solution and
we need to find a better one.
Jira issue: Reduce websocket communication by unicasting instead of
broadcasting note list (https://issues.apache.org/jira/browse/ZEPPELIN-820)
Prasad
On Mon, Jun 20, 2016 at 5:04 PM, Johnny W. <jzw.ser...@gmail.com> wrote:
Hi zeppelin-users,
This is my first email to the top-level mailing list. Congratulations for
graduation!
We are hitting some performance issues when multiple users are connected to the
Zeppelin server. From the stack trace, many of the connections are blocked on a
HashMap, which is locked by
org.apache.zeppelin.socket.NotebookServer.broadcastNote.
Our largest notebook is around 800K, and there are around 10 - 20 connections
to the Zeppelin server. I think it should be we are broadcasting some large
amount of data to multiple users, and some slow connections hang the whole web
interface.
Is there anyway to reduce the number of broadcasts to improve the web
performance? It is fine for us to refresh and get updates. I've attached the
full stack trace of this issue as well.
Thanks!
Johnny
Blocking Thread:
--
"qtp1874598090-2478" prio=10 tid=0x00007f2fb0003800 nid=0x3373 waiting on
condition [0x00007f329ebe9000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000704e15db0> (a
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)
at
org.eclipse.jetty.util.SharedBlockingCallback$Blocker.block(SharedBlockingCallback.java:219)
at
org.eclipse.jetty.websocket.common.BlockingWriteCallback$WriteBlocker.block(BlockingWriteCallback.java:83)
at
org.eclipse.jetty.websocket.common.WebSocketRemoteEndpoint.blockingWrite(WebSocketRemoteEndpoint.java:107)
at
org.eclipse.jetty.websocket.common.WebSocketRemoteEndpoint.sendString(WebSocketRemoteEndpoint.java:387)
at
org.apache.zeppelin.socket.NotebookSocket.send(NotebookSocket.java:69)
at
org.apache.zeppelin.socket.NotebookServer.broadcast(NotebookServer.java:304)
- locked <0x00000007006b6100> (a java.util.HashMap)
at
org.apache.zeppelin.socket.NotebookServer.broadcastNote(NotebookServer.java:384)
at
org.apache.zeppelin.socket.NotebookServer.updateNote(NotebookServer.java:492)
at
org.apache.zeppelin.socket.NotebookServer.onMessage(NotebookServer.java:181)
at
org.apache.zeppelin.socket.NotebookSocket.onWebSocketText(NotebookSocket.java:56)
at
org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextMessage(JettyListenerEventDriver.java:128)
at
org.eclipse.jetty.websocket.common.message.SimpleTextMessage.messageComplete(SimpleTextMessage.java:69)
at
org.eclipse.jetty.websocket.common.events.AbstractEventDriver.appendMessage(AbstractEventDriver.java:65)
at
org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextFrame(JettyListenerEventDriver.java:122)
at
org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:161)
at
org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:309)
at
org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:214)
at
org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:220)
at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:258)
at
org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.readParse(AbstractWebSocketConnection.java:632)
at
org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:480)
at
org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
at
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
at
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
at java.lang.Thread.run(Thread.java:745)
Blocked Thread:
--
"qtp1874598090-2498" prio=10 tid=0x00007f306000f800 nid=0x4075 waiting for
monitor entry [0x00007f329eae9000]
java.lang.Thread.State: BLOCKED (on object monitor)
at
org.apache.zeppelin.socket.NotebookServer.addConnectionToNote(NotebookServer.java:229)
- waiting to lock <0x00000007006b6100> (a java.util.HashMap)
at
org.apache.zeppelin.socket.NotebookServer.sendNote(NotebookServer.java:432)
at
org.apache.zeppelin.socket.NotebookServer.onMessage(NotebookServer.java:145)
at
org.apache.zeppelin.socket.NotebookSocket.onWebSocketText(NotebookSocket.java:56)
at
org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextMessage(JettyListenerEventDriver.java:128)
at
org.eclipse.jetty.websocket.common.message.SimpleTextMessage.messageComplete(SimpleTextMessage.java:69)
at
org.eclipse.jetty.websocket.common.events.AbstractEventDriver.appendMessage(AbstractEventDriver.java:65)
at
org.eclipse.jetty.websocket.common.events.JettyListenerEventDriver.onTextFrame(JettyListenerEventDriver.java:122)
at
org.eclipse.jetty.websocket.common.events.AbstractEventDriver.incomingFrame(AbstractEventDriver.java:161)
at
org.eclipse.jetty.websocket.common.WebSocketSession.incomingFrame(WebSocketSession.java:309)
at
org.eclipse.jetty.websocket.common.extensions.ExtensionStack.incomingFrame(ExtensionStack.java:214)
at
org.eclipse.jetty.websocket.common.Parser.notifyFrame(Parser.java:220)
at org.eclipse.jetty.websocket.common.Parser.parse(Parser.java:258)
at
org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.readParse(AbstractWebSocketConnection.java:632)
at
org.eclipse.jetty.websocket.common.io.AbstractWebSocketConnection.onFillable(AbstractWebSocketConnection.java:480)
at
org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
at
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
at
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
at java.lang.Thread.run(Thread.java:745)
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