Hello,

A bit of an ugly hack, but maybe you could manually create a class
named exactly io.relayr.counter.FttCounter$$anon$71$$anon$33, and
copy-paste into it the code that the macro is expanded into [1]?

Best,
Gábor

[1] 
https://stackoverflow.com/questions/11677609/how-do-i-print-an-expanded-macro-in-scala





On Tue, Apr 10, 2018 at 6:06 PM, Petter Arvidsson
<petter.arvids...@relayr.io> wrote:
> Hello everyone,
>
> We are trying to recover state from a snapshot which we can no longer load.
> When it is loaded we receive the following exception:
> java.lang.ClassNotFoundException:
> io.relayr.counter.FttCounter$$anon$71$$anon$33
> This, via a couple more exceptions, leads to:
> java.io.IOException: Unloadable class for type serializer.
>
> The cause of this behavior is an implicit macro that is part of the scala
> API package,
> https://github.com/apache/flink/blob/release-1.4/flink-scala/src/main/scala/org/apache/flink/api/scala/package.scala#L46.
> This macro generates an anonymous class implementing TypeInformation for
> classes that lack it. In our case it seems to have generated
> "io.relayr.counter.FttCounter$$anon$71$$anon$33" which does not have a
> stable name. When we change the class implementing the job, the name of this
> anonymous class changes and we can no longer load the snapshot.
>
> To solve the problem we introduced an explicit TypeInformation instance
> instead, which makes new instances of the job work properly. The problem is
> that this new version is no longer compatible with the old state (loading it
> generates the same exception), since the original TypeInformation is no
> longer generated. This is due to the explicitly provided instance preventing
> the macro from being executed.
>
> Did anyone else experience this or a similar problem? Is there a good way to
> get out of this situation, i.e. how could we migrate the snapshot to one
> where the state points to a TypeInformation instance with a stable class
> name and not the macro generated one without losing the state?
>
> We are using Flink 1.4.2.
>
> Regards,
> Petter

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