[jira] [Created] (FLINK-4169) CEP Does Not Work with RocksDB StateBackend

["Aljoscha Krettek (JIRA)" <ji...@apache.org>]

Aljoscha Krettek created FLINK-4169:
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             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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