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From "Aljoscha Krettek (JIRA)" <j...@apache.org>
Subject [jira] [Created] (FLINK-4169) CEP Does Not Work with RocksDB StateBackend
Date Thu, 07 Jul 2016 12:44:11 GMT
Aljoscha Krettek created FLINK-4169:

             Summary: CEP Does Not Work with RocksDB StateBackend
                 Key: FLINK-4169
                 URL: https://issues.apache.org/jira/browse/FLINK-4169
             Project: Flink
          Issue Type: Bug
          Components: CEP
    Affects Versions: 1.0.3, 1.0.2, 1.0.1, 1.0.0, 1.1.0
            Reporter: Aljoscha Krettek
            Priority: Blocker

A job will never match any patterns because {{ValueState.update()}} is not called in the keyed
CEP operators for updating the {{NFA}} state and the priority queue state.

The reason why it works for other state backends is that they are very lax in their handling
of state: if the object returned from {{ValueState.value())}} is mutable changes to this will
be reflected in checkpoints even if {{ValueState.update()}} is not called. RocksDB, on the
other hand, does always deserialize/serialize state values when accessing/updating them, so
changes to the returned object will not be reflected in the state unless {{update()}} is called.

We should fix this and also add a test for it. This might be tricky because we have to pull
together RocksDB and CEP.

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