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  1. IMPALA
  2. IMPALA-7551

Inaccurate timeline for "Rows Available"

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      Description

      While debugging IMPALA-6932, it was noticed that the "Rows Available" metric in the query profile was a short duration (~ 1 second) for a long running limit 1 query (~ 1 hour).

      Currently, it tracks when Open() from the top-most node in the plan returns, not when the first row is actually produced. This can be misleading. A better timeline would be to return true when the first non-empty batch was added to the PlanRootSink. 

      We should consider changing the definition of the FINISHED state accordingly as well, so that we don't transition to FINISHED until a row is actually available to fetch immediately.

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            • Assignee:
              stakiar Sahil Takiar
              Reporter:
              poojanilangekar Pooja Nilangekar
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