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From Sean Owen <>
Subject Re: Kryo serializer slower than Java serializer for Spark Streaming
Date Thu, 06 Oct 2016 14:08:47 GMT
It depends a lot on your data. If it's a lot of custom types then Kryo
doesn't have a lot of advantage, although, you want to make sure to
register all your classes with kryo (and consider setting the flag that
requires kryo registration to ensure it) because that can let kryo avoid
writing a bunch of class names, which Java serialization always would.

On Thu, Oct 6, 2016 at 2:47 PM Rajkiran Rajkumar <>

> Hi,
> I am running a Spark Streaming application which reads from a Kinesis
> stream and processes data. The application is run on EMR. Recently, we
> tried moving from Java's inbuilt serializer to Kryo serializer. To quantify
> the performance improvement, I tried pumping 30000 input records to the
> application over a period of 5 minutes. Based on the task deserialization
> time, I have the following data.
> Using Java serializer- Median 3 ms, Mean 8.21 ms
> Using Kryo serializer- Median 4 ms, Mean 9.64 ms
> Here, we see that Kryo serializer is slower than Java serializer. Looking
> for some advice regarding items that I might have missed taking into
> account. Please let me know if more information is needed.
> Thanks,
> Rajkiran

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