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From Josh <jof...@gmail.com>
Subject How to avoid breaking states when upgrading Flink job?
Date Wed, 29 Jun 2016 19:00:13 GMT
Hi all,
Is there any information out there on how to avoid breaking saved
states/savepoints when making changes to a Flink job and redeploying it?

I want to know how to avoid exceptions like this:

java.lang.RuntimeException: Failed to deserialize state handle and
setup initial operator state.
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:551)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException:
com.me.flink.MyJob$$anon$1$$anon$7$$anon$4


The best information I could find in the docs is here:

https://ci.apache.org/projects/flink/flink-docs-master/apis/streaming/savepoints.html


Having made the suggested changes to my job (i.e. giving a uid to
every stateful sink and map function), what changes to the
job/topology are then allowed/not allowed?


If I'm 'naming' my states by providing uids, why does Flink need to
look for a specific class, like
com.me.flink.MyJob$$anon$1$$anon$7$$anon$4 ?


Thanks for any advice,

Josh

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