Todd Lipcon created KUDU-2380:
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Summary: Selective predicates when selecting high number of
columns burns CPU in SerializeRowBlock
Key: KUDU-2380
URL: https://issues.apache.org/jira/browse/KUDU-2380
Project: Kudu
Issue Type: Improvement
Components: tserver
Reporter: Todd Lipcon
Assignee: Todd Lipcon
Testing a table with 280 columns, I found the following performance
characteristic:
- scanning all 280 columns with a selective non-key predicate which matches 0
rows took 8.28s
- scanning no columns (count query) with the same predicate which matches 0
rows took 314ms.
This suggests that we are burning 96% of our CPU doing useless work for this
query.
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