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https://issues.apache.org/jira/browse/PHOENIX-7106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17815113#comment-17815113
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ASF GitHub Bot commented on PHOENIX-7106:
-----------------------------------------
virajjasani commented on code in PR #1736:
URL: https://github.com/apache/phoenix/pull/1736#discussion_r1480936899
##########
phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/GroupedAggregateRegionObserver.java:
##########
@@ -371,12 +425,32 @@ private static class UnorderedGroupByRegionScanner
extends BaseRegionScanner {
private final long pageSizeMs;
private RegionScanner regionScanner = null;
private final GroupByCache groupByCache;
+ private final Scan scan;
+ private final byte[] scanStartRowKey;
+ private final boolean includeStartRowKey;
+ private final byte[] prevScanStartRowKey;
+ private final Boolean prevScanIncludeStartRowKey;
+ private boolean firstScan = true;
+ private boolean updateScannerBasedOnPrevRowKey = false;
+ private byte[] lastReturnedRowKey = null;
private UnorderedGroupByRegionScanner(final
ObserverContext<RegionCoprocessorEnvironment> c,
final Scan scan, final
RegionScanner scanner, final List<Expression> expressions,
final ServerAggregators
aggregators, final long limit, final long pageSizeMs) {
super(scanner);
this.region = c.getEnvironment().getRegion();
+ this.scan = scan;
+ // If scan start rowkey is empty, use region boundaries. Reverse
region boundaries
+ // for reverse scan.
+ scanStartRowKey = scan.getStartRow().length > 0 ?
scan.getStartRow() :
+ (scan.isReversed() ? region.getRegionInfo().getEndKey() :
+ region.getRegionInfo().getStartKey());
+ includeStartRowKey = scan.includeStartRow();
+ // Retrieve start rowkey of the previous scan. This would be
different than
+ // current scan start rowkey if the region has recently moved or
split or merged.
+ this.prevScanStartRowKey =
+
scan.getAttribute(BaseScannerRegionObserverConstants.SCAN_ACTUAL_START_ROW);
+ this.prevScanIncludeStartRowKey = true;
Review Comment:
The reason why it is kept true here is because everytime when we set
`_ScanActualStartRow` scan attribute, we always use `scan#withStartRow`
function which internally sets include start row as true. So, yes this never
changes, this is meant to be true only, even across region moves after scanner
resets.
> Data Integrity issues due to invalid rowkeys returned by various coprocessors
> -----------------------------------------------------------------------------
>
> Key: PHOENIX-7106
> URL: https://issues.apache.org/jira/browse/PHOENIX-7106
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 5.2.0, 5.1.4
> Reporter: Viraj Jasani
> Assignee: Viraj Jasani
> Priority: Blocker
> Fix For: 5.2.0, 5.1.4
>
>
> HBase scanner interface expects server to perform scan of the cells from
> HFile or Block cache and return consistent data i.e. rowkey of the cells
> returned should stay in the range of the scan boundaries. When a region moves
> and scanner needs reset, or if the current row is too large and the server
> returns partial row, the subsequent scanner#next is supposed to return
> remaining cells. When this happens, cell rowkeys returned by servers i.e. any
> coprocessors is expected to be in the scan boundary range so that server can
> reliably perform its validation and return remaining cells as expected.
> Phoenix client initiates serial or parallel scans from the aggregators based
> on the region boundaries and the scan boundaries are sometimes adjusted based
> on where optimizer provided key ranges, to include tenant boundaries, salt
> boundaries etc. After the client opens the scanner and performs scan
> operation, some of the coprocs return invalid rowkey for the following cases:
> # Grouped aggregate queries
> # Some Ungrouped aggregate queries
> # Offset queries
> # Dummy cells returned with empty rowkey
> # Update statistics queries
> # Uncovered Index queries
> # Ordered results at server side
> # ORDER BY DESC on rowkey
> # Global Index read-repair
> # Paging region scanner with HBase scanner reopen
> # ORDER BY on non-pk column(s) with/without paging
> # GROUP BY on non-pk column(s) with/without paging
> Since many of these cases return reserved rowkeys, they are likely not going
> to match scan or region boundaries. It has potential to cause data integrity
> issues in certain scenarios as explained above. Empty rowkey returned by
> server can be treated as end of the region scan by HBase client.
> With the paging feature enabled, if the page size is kept low, we have higher
> chances of scanners returning dummy cell, resulting in increased num of RPC
> calls for better latency and timeouts. We should return only valid rowkey in
> the scan range for all the cases where we perform above mentioned operations
> like complex aggregate or offset queries etc.
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