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https://issues.apache.org/jira/browse/KAFKA-8367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16842778#comment-16842778
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Sophie Blee-Goldman edited comment on KAFKA-8367 at 5/17/19 11:11 PM:
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Bummer. Thanks for helping with the investigation – it'll be helpful to know if
this affects 2.1 as well.
Was your 2.0.1 app basically the same as your 2.2 app? Actually, would you be
able to share your code? (No chance this is just an unclosed iterator pinning
resources I assume)
was (Author: ableegoldman):
Bummer. Thanks for helping with the investigation – it'll be helpful to know if
this affects 2.1 as well.
Was your 2.0.1 app basically the same as your 2.2 app? No chance of a new
iterator that isn't being closed causing this?
> Non-heap memory leak in Kafka Streams
> -------------------------------------
>
> Key: KAFKA-8367
> URL: https://issues.apache.org/jira/browse/KAFKA-8367
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.2.0
> Reporter: Pavel Savov
> Priority: Major
> Attachments: memory-prod.png, memory-test.png
>
>
> We have been observing a non-heap memory leak after upgrading to Kafka
> Streams 2.2.0 from 2.0.1. We suspect the source to be around RocksDB as the
> leak only happens when we enable stateful stream operations (utilizing
> stores). We are aware of *KAFKA-8323* and have created our own fork of 2.2.0
> and ported the fix scheduled for release in 2.2.1 to our fork. It did not
> stop the leak, however.
> We are having this memory leak in our production environment where the
> consumer group is auto-scaled in and out in response to changes in traffic
> volume, and in our test environment where we have two consumers, no
> autoscaling and relatively constant traffic.
> Below is some information I'm hoping will be of help:
> * RocksDB Config:
> Block cache size: 4 MiB
> Write buffer size: 2 MiB
> Block size: 16 KiB
> Cache index and filter blocks: true
> Manifest preallocation size: 64 KiB
> Max write buffer number: 3
> Max open files: 6144
>
> * Memory usage in production
> The attached graph (memory-prod.png) shows memory consumption for each
> instance as a separate line. The horizontal red line at 6 GiB is the memory
> limit.
> As illustrated on the attached graph from production, memory consumption in
> running instances goes up around autoscaling events (scaling the consumer
> group either in or out) and associated rebalancing. It stabilizes until the
> next autoscaling event but it never goes back down.
> An example of scaling out can be seen from around 21:00 hrs where three new
> instances are started in response to a traffic spike.
> Just after midnight traffic drops and some instances are shut down. Memory
> consumption in the remaining running instances goes up.
> Memory consumption climbs again from around 6:00AM due to increased traffic
> and new instances are being started until around 10:30AM. Memory consumption
> never drops until the cluster is restarted around 12:30.
>
> * Memory usage in test
> As illustrated by the attached graph (memory-test.png) we have a fixed number
> of two instances in our test environment and no autoscaling. Memory
> consumption rises linearly until it reaches the limit (around 2:00 AM on
> 5/13) and Mesos restarts the offending instances, or we restart the cluster
> manually.
>
> * No heap leaks observed
> * Window retention: 2 or 11 minutes (depending on operation type)
> * Issue not present in Kafka Streams 2.0.1
> * No memory leak for stateless stream operations (when no RocksDB stores are
> used)
>
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