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https://issues.apache.org/jira/browse/FLINK-9009?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16404850#comment-16404850
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Chesnay Schepler edited comment on FLINK-9009 at 3/19/18 1:59 PM:
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The error message is due to netty's leak detector which complains if one JVM
uses more than 4 timers, which in this case is completely expected. See
[|https://github.com/netty/netty/issues/6225]. This however is just a logging
message and does not fail the job.
In other words, there is no leak, Flink works as expected, and the job fails
because not enough memory is given to the JVM. 500mb for a job with a
parallelism of 20 seems a bit low.
was (Author: zentol):
The error message is due to netty's leak detector which complains if one JVM
uses more than 4 timers, which in this case is completely expected. See
[|https://github.com/netty/netty/issues/6225]. This however is just a logging
message and does not fail the job.
In other words, there is no leak, Flink works as expected, and the job fails
because not enough memory is given to the JVM.
> Error| You are creating too many HashedWheelTimer instances.
> HashedWheelTimer is a shared resource that must be reused across the
> application, so that only a few instances are created.
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-9009
> URL: https://issues.apache.org/jira/browse/FLINK-9009
> Project: Flink
> Issue Type: Bug
> Environment: Pass platform: Openshift
> Reporter: Pankaj
> Priority: Blocker
>
> Steps to reproduce:
> 1- Flink with Kafka as a consumer -> Writing stream to Cassandra using flink
> cassandra sink.
> 2- In memory Job manager and task manager with checkpointing 5000ms.
> 3- env.setpararllelism(10)-> As kafka topic has 10 partition.
> 4- There are around 13 unique streams in a single flink run time environment
> which are reading from kafka -> processing and writing to cassandra.
> Hardware: CPU 200 milli core . It is deployed on Paas platform on one node
> Memory: 526 MB.
>
> When i start the server, It starts flink and all off sudden stops with above
> error. It also shows out of memory error.
>
> It would be nice if any body can suggest if something is wrong.
>
> Maven:
> flink-connector-cassandra_2.11: 1.3.2
> flink-streaming-java_2.11: 1.4.0
> flink-connector-kafka-0.11_2.11:1.4.0
>
>
>
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