Details
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Bug
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Status: Open
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Major
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Resolution: Unresolved
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None
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None
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None
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ghx-label-6
Description
IMPALA-8825 added the following explanation of the counter RowMaterializationTimer
/// Tracks the time spent materializing rows and converting them into a QueryResultSet.
/// The QueryResultSet format used depends on the client, for Beeswax clients an ASCII
/// representation is used, whereas for HS2 clients (using TCLIService.thrift) rows are
/// converted into a TRowSet. Materializing rows includes evaluating any yet unevaluated
/// expressions using ScalarExprEvaluators.
This isn't accurate because the actual timer measures time taken running Coordinator::GetNext which can block if any downstream operators in the plan take a long time to materialize rows.
We should revise the explanation of RowMaterializationTimer and consider adding a separate timer that truly measures the amount of time taken to materialize rows (e.g. measure time taken in QueryResultSet::AddRows).
Attachments
Issue Links
- is related to
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IMPALA-8825 Add additional counters to PlanRootSink
- Resolved
- relates to
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IMPALA-8656 Support for eagerly fetching and spooling all query result rows
- Resolved