HBASE-30351 ROWS_SCANNED scan metric double-counts rows passing the filter when the scan uses the joined heap - #8596
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HBASE-30351 ROWS_SCANNED scan metric double-counts rows passing the filter when the scan uses the joined heap#8596eomiks wants to merge 1 commit into
eomiks wants to merge 1 commit into
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…ilter when the scan uses the joined heap
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Fixes the ROWS_SCANNED server-side scan metric double-counting rows that pass the filter when the scan uses the joined heap, i.e.
Scan#setLoadColumnFamiliesOnDemand(true)with a filter marking some families as non-essential (Filter#isFamilyEssential).RegionScannerImpl#populateResultincrements the metric whenever the given heap finishes the current row, andpopulateFromJoinedHeapgoes through the same method for the non-essential families, so a row passing the filter was counted twice (once for the store heap, once for the joined heap). The row-scanned event is now recorded only when populating from the store heap.The new test in
TestServerSideScanMetricsFromClientSidereproduces the issue with stock filters (SingleColumnValueFilterwithsetFilterIfMissing(true)on a two-family table): before the fix ROWS_SCANNED reported 15 for a scan over 10 rows with 5 matching, after the fix it reports 10.Details: https://issues.apache.org/jira/browse/HBASE-30351