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Posted to issues@impala.apache.org by "Tim Armstrong (JIRA)" <ji...@apache.org> on 2019/04/10 20:09:00 UTC

[jira] [Created] (IMPALA-8405) Document UDA state machine

Tim Armstrong created IMPALA-8405:
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             Summary: Document UDA state machine
                 Key: IMPALA-8405
                 URL: https://issues.apache.org/jira/browse/IMPALA-8405
             Project: IMPALA
          Issue Type: Improvement
          Components: Docs
            Reporter: Tim Armstrong


The documentation in "The Underlying Functions for a UDA" doesn't do a good job of explaining the state transitions that a UDA can go through. E.g. when is Serialize() called. It's complicated because data needs to be serialized to go over the network, but *sometimes* is serialized to spill to disk, which changes the sequence of function calls.

See https://community.cloudera.com/t5/Interactive-Short-cycle-SQL/Function-execution-flow-in-UDAs-and-memory-implications-for/m-p/88892#M5532?eid=1&aid=1 for a user who is trying to understand this.



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