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https://issues.apache.org/jira/browse/STORM-2853?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16360579#comment-16360579
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Adam commented on STORM-2853:
-----------------------------

[Jungtaek 
Lim|https://issues.apache.org/jira/secure/ViewProfile.jspa?name=kabhwan] 

Yes, stateful bolts implemented by a user. Our current application fortunately 
wouldn't run into such a situation. So it is more of a theoretical scenario.

So one can imagine a case e.g. of a bolt that emits tuples in batches. Let's 
assume it stores them somewhere e.g. in an external cache. Then when the 
topology is deactivated it could want to flush the current batch (e.g. after a 
timeout which I can imagine is triggered by a tick tuple in most 
implementations). So if the JVM restart happens before the timeout, the flush 
will not happen until the topology is activated and receives the first tick 
tuple. Whereas it would happen if the JVM hasn't restarted, that's the 
inconsistency. It's is an edge case scenario of course.

> Deactivated topologies cause high cpu utilization
> -------------------------------------------------
>
>                 Key: STORM-2853
>                 URL: https://issues.apache.org/jira/browse/STORM-2853
>             Project: Apache Storm
>          Issue Type: Bug
>          Components: storm-core
>    Affects Versions: 1.1.0
>            Reporter: Stuart
>            Assignee: Jungtaek Lim
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 2.0.0, 1.2.0, 1.1.2, 1.0.6
>
>         Attachments: exclamation.zip
>
>          Time Spent: 1h 20m
>  Remaining Estimate: 0h
>
> The issue is there is high cpu usage for deactivated apache storm topologies. 
>  I can reliably re-create the issue using the steps below but I haven't 
> identified the exact cause or a solution yet.
> The environment is a storm cluster on which 1 topology is running (The 
> topology is extremely simple, I used the exclamation example).  It is 
> INACTIVE.  Initially there is normal CPU usage.  However, when I kill all 
> topology JVM processes on all supervisors and let Storm restart them again, I 
> find that some time later (~9 hours) the CPU usage per JVM process rises to 
> nearly 100%.  I have tested an ACTIVE topology and this does not happen with 
> it.  I have also tested more than one topology and observe the same results 
> when they're in the INACTIVE state.
> ***Steps to re-create:***
>  1. Run 1 topology on an Apache Storm cluster
>  2. Deactivate it
>  3. Kill **all** topology JVM processes on all supervisors (Storm will 
> restart them)
>  4. Observe the CPU usage on Supervisors rise to nearly 100% for all 
> **INACTIVE** topology JVM processes.
> ***Environment***
> Apache Storm 1.1.0 running on 3 VMs (1 nimbus and 2 supervisors).
> Cluster Summary:
>  - Supervisors: 2 
>  - Used Slots: 2 
>  - Available Slots: 38 
>  - Total Slots: 40
>  - Executors: 50 
>  - Tasks: 50
> the topology has 2 workers and 50 executors/tasks (threads).
> ***Investigation so far:***
> Apart from being able to reliably re-create the issue, I have identified, for 
> the affected topology JVM process, the threads using the most CPU.  There are 
> 102 threads total in the process, 97 blocked, 5 IN_NATIVE.  The threads using 
> the most CPU are identical and there are 23 of them (all in BLOCKED state):
>     Thread 28558: (state = BLOCKED)
>      - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; 
> information may be imprecise)
>      - java.util.concurrent.locks.LockSupport.parkNanos(long) @bci=11, 
> line=338 (Compiled frame)
>      - com.lmax.disruptor.MultiProducerSequencer.next(int) @bci=82, line=136 
> (Compiled frame)
>      - com.lmax.disruptor.RingBuffer.next(int) @bci=5, line=260 (Interpreted 
> frame)
>      - 
> org.apache.storm.utils.DisruptorQueue.publishDirect(java.util.ArrayList, 
> boolean) @bci=18, line=517 (Interpreted frame)
>      - 
> org.apache.storm.utils.DisruptorQueue.access$1000(org.apache.storm.utils.DisruptorQueue,
>  java.util.ArrayList, boolean) @bci=3, line=61 (Interpreted frame)
>      - 
> org.apache.storm.utils.DisruptorQueue$ThreadLocalBatcher.flush(boolean) 
> @bci=50, line=280 (Interpreted frame)
>      - org.apache.storm.utils.DisruptorQueue$Flusher.run() @bci=55, line=303 
> (Interpreted frame)
>      - java.util.concurrent.Executors$RunnableAdapter.call() @bci=4, line=511 
> (Compiled frame)
>      - java.util.concurrent.FutureTask.run() @bci=42, line=266 (Compiled 
> frame)
>      - 
> java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker)
>  @bci=95, line=1142 (Compiled frame)
>      - java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=5, line=617 
> (Interpreted frame)
>      - java.lang.Thread.run() @bci=11, line=745 (Interpreted frame)
> I identified this thread by using `jstack` to get a thread dump for the 
> process:
>  
>     jstack -F <pid> > jstack<pid>.txt
> and `top` to identify the threads within the process using the most CPU:
>     top -H -p <pid> 



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