[jira] [Created] (SPARK-29314) ProgressReporter.extractStateOperatorMetrics should not overwrite updated as 0 when it actually runs a batch even with no data

["Jungtaek Lim (Jira)" <ji...@apache.org>]

Jungtaek Lim created SPARK-29314:
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             Summary: ProgressReporter.extractStateOperatorMetrics should not overwrite updated as 0 when it actually runs a batch even with no data
                 Key: SPARK-29314
                 URL: https://issues.apache.org/jira/browse/SPARK-29314
             Project: Spark
          Issue Type: Bug
          Components: Structured Streaming
    Affects Versions: 2.4.4, 3.0.0
            Reporter: Jungtaek Lim


SPARK-24156 brought the ability to run a batch without actual data to enable fast state cleanup as well as emit evicted outputs without waiting actual data to come.

This breaks some assumption on `ProgressReporter.extractStateOperatorMetrics`. See comment in source code:

{code:java}
// lastExecution could belong to one of the previous triggers if `!hasNewData`.
// Walking the plan again should be inexpensive.
{code}

and newNumRowsUpdated is replaced to 0 if hasNewData is false. It makes sense if we copy progress from previous execution (which means no batch is run for this time), but after SPARK-24156 the precondition is broken. 

Spark should still replace the value of newNumRowsUpdated with 0 if there's no batch being run and it needs to copy the old value from previous execution, but it shouldn't touch the value if it runs a batch for no data.



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