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https://issues.apache.org/jira/browse/HBASE-19818?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16337123#comment-16337123
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Guanghao Zhang commented on HBASE-19818:
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Open HBASE-19855 to refactor RegionScannerImpl.nextInternal method.
> Scan time limit not work if the filter always filter row key
> ------------------------------------------------------------
>
> Key: HBASE-19818
> URL: https://issues.apache.org/jira/browse/HBASE-19818
> Project: HBase
> Issue Type: Bug
> Affects Versions: 3.0.0, 2.0.0-beta-2
> Reporter: Guanghao Zhang
> Assignee: Guanghao Zhang
> Priority: Major
> Attachments: HBASE-19818.master.003.patch
>
>
> [https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java]
> nextInternal() method.
> {code:java}
> // 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;
> }
> {code}
> 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.
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