zhimin wu created KYLIN-5817:
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Summary: After sending the query, the number of scanRows and
scanBytes in response are inaccurate
Key: KYLIN-5817
URL: https://issues.apache.org/jira/browse/KYLIN-5817
Project: Kylin
Issue Type: Improvement
Components: Query Engine
Affects Versions: 5.0-beta
Reporter: zhimin wu
Fix For: 5.0.0
h3. Background
When KE calls the query interface, it is found that the scan row count
{{scanRows}} and scan byte count {{scanBytes}} in the response are not accurate.
h3. Root Cause
The query interface internally calls the
{{collectAdaptiveSparkPlanExecMetrics}} method of {{{}QueryMetricUtils{}}}.
When iterating through {{{}exec.children.foreach{}}}, if the {{child}} is a
{{{}SparkPlan{}}}, each time the results of the new {{child}} overwrite the
{{newScanRow}} and {{newScanBytes}} variables without adding them up.
h3. Dev Design
To address the issue, replace the assignment operator {{=}} with the compound
addition assignment operator {{+=}} to ensure that the results are properly
accumulated. This change will allow for the correct aggregation of scan row
count and scan byte count in each iteration.
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