[HBASE-19818] Scan time limit not work if the filter always filter row key

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1, 2.0.0-beta-2
• Fix Version/s: 2.0.0-beta-2, 2.0.0
• Assignee: Guanghao Zhang
• Reporter: Guanghao Zhang
• Created: 18/Jan/18 02:22
• Updated: 01/Aug/18 06:23
• Resolved: 26/Jan/18 09:08

Description

https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java

nextInternal() method.

// Check if rowkey filter wants to exclude this row. If so, loop to next.
 // Technically, if we hit limits before on this row, we don't need this call.
 if (filterRowKey(current)) {
 incrementCountOfRowsFilteredMetric(scannerContext);
 // early check, see HBASE-16296
 if (isFilterDoneInternal()) {
 return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
 }
 // Typically the count of rows scanned is incremented inside #populateResult. However,
 // here we are filtering a row based purely on its row key, preventing us from calling
 // #populateResult. Thus, perform the necessary increment here to rows scanned metric
 incrementCountOfRowsScannedMetric(scannerContext);
 boolean moreRows = nextRow(scannerContext, current);
 if (!moreRows) {
 return scannerContext.setScannerState(NextState.NO_MORE_VALUES).hasMoreValues();
 }
 results.clear();
 continue;
 }

// Ok, we are good, let's try to get some results from the main heap.
 populateResult(results, this.storeHeap, scannerContext, current);
 if (scannerContext.checkAnyLimitReached(LimitScope.BETWEEN_CELLS)) {
 if (hasFilterRow) {
 throw new IncompatibleFilterException(
 "Filter whose hasFilterRow() returns true is incompatible with scans that must "
 + " stop mid-row because of a limit. ScannerContext:" + scannerContext);
 }
 return true;
 }

If filterRowKey always return ture, then it skip to checkAnyLimitReached. For batch/size limit, it is ok to skip as we don't read anything. But for time limit, it is not right. If the filter always filter row key, we will stuck here for a long time.

Issue Links

• links to: Review Board (master)