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From Robert Metzger <rmetz...@apache.org>
Subject Re: Flink + Kafka + Scalabuff issue
Date Thu, 05 May 2016 11:43:22 GMT
Hi Alex,
thanks for the update. I'm happy to hear you were able to resolve the issue.
How are the other ad-hoc streaming pipelines setup?
Maybe these pipelines use a different threading model than Flink. In Flink,
we often have many instances of the same serializer running in the same
JVM. Maybe there are some static lookup tables in the generated code that
are accessed in parallel by many threads in the flink case, leading to
these issues?

On Tue, May 3, 2016 at 5:14 PM, Alexander Gryzlov <alex.gryzlov@gmail.com>

> Hello,
> Just to follow up on this issue: after collecting some data and setting up
> additional tests we have managed to pinpoint the issue to the the
> ScalaBuff-generated code that decodes enumerations. After switching to use
> ScalaPB generator instead, the problem was gone.
> One thing peculiar about this bug, however, is that it seems to manifest
> only on Flink. We have a number of ad-hoc streaming pipelines (without
> Flink) that are still using the very same decoder code and have been
> running for weeks without seemingly experiencing any memory or performance
> issues. The versions of Flink that we saw this happening this on are 1.0
> and 1.0.1.
> Alex
> On Tue, Apr 19, 2016 at 1:11 PM, Robert Metzger <rmetzger@apache.org>
> wrote:
>> Hi Alex,
>> I suspect its a GC issue with the code generated by ScalaBuff. Can you
>> maybe try to do something like a standalone test where use use a
>> while(true) loop to see how fast you can deserialize elements from your Foo
>> type?
>> Maybe you'll find that the JVM is growing all the time. Then there's
>> probably a memory leak somewhere.
>> On Tue, Apr 19, 2016 at 11:42 AM, Ufuk Celebi <uce@apache.org> wrote:
>>> Hey Alex,
>>> (1) Which Flink version are you using for this?
>>> (2) Can you also get a heap dump after the job slows down? Slow downs
>>> like this are often caused by some component leaking memory, maybe in
>>> Flink, maybe the Scalabuff deserializer. Can you also share the Foo
>>> code?
>>> – Ufuk
>>> On Mon, Apr 18, 2016 at 4:36 PM, Alexander Gryzlov
>>> <alex.gryzlov@gmail.com> wrote:
>>> > Hello,
>>> >
>>> > Has anyone tried using ScalaBuff
>>> > (https://github.com/SandroGrzicic/ScalaBuff) with Flink? We’re trying
>>> to
>>> > consume Protobuf messages from Kafka 0.8 and have hit a performance
>>> issue.

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