tkhurana commented on code in PR #1736:
URL: https://github.com/apache/phoenix/pull/1736#discussion_r1480654509
##########
phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/GroupedAggregateRegionObserver.java:
##########
@@ -411,6 +487,115 @@ private UnorderedGroupByRegionScanner(final
ObserverContext<RegionCoprocessorEnv
@Override
public boolean next(List<Cell> resultsToReturn) throws IOException {
+ if (firstScan && prevScanStartRowKey != null &&
prevScanIncludeStartRowKey != null) {
+ firstScan = false;
+ if (scanStartRowKey.length > 0 &&
!ScanUtil.isLocalIndex(scan)) {
+ if (Bytes.compareTo(prevScanStartRowKey, scanStartRowKey)
!= 0 ||
+ prevScanIncludeStartRowKey != includeStartRowKey) {
+ LOGGER.info("Region has moved.. Prev scan start rowkey
{} is not same as" +
+ " current scan start rowkey {}",
+ Bytes.toStringBinary(prevScanStartRowKey),
+ Bytes.toStringBinary(scanStartRowKey));
+ // If region has moved in the middle of the scan
operation, after resetting
+ // the scanner, hbase client uses (latest received
rowkey + \x00) as new
+ // start rowkey for resuming the scan operation on the
new scanner.
+ if (Bytes.compareTo(
+ ByteUtil.concat(prevScanStartRowKey,
Bytes.toBytesBinary("\\x00")),
+ scanStartRowKey) == 0) {
+
scan.setAttribute(QueryServices.PHOENIX_PAGING_NEW_SCAN_START_ROWKEY,
+ prevScanStartRowKey);
+ scan.setAttribute(
+
QueryServices.PHOENIX_PAGING_NEW_SCAN_START_ROWKEY_INCLUDE,
+ Bytes.toBytes(prevScanIncludeStartRowKey));
+ } else {
+ // This happens when the server side scanner has
already sent some
+ // rows back to the client and region has moved,
so now we need to
+ // use updateScannerBasedOnPrevRowKey flag and
also reset the scanner
+ // at paging region scanner level to re-read the
previously sent
+ // values in order to re-compute the aggregation
and then return
+ // only the next rowkey that was not yet sent back
to the client.
+ updateScannerBasedOnPrevRowKey = true;
+
scan.setAttribute(QueryServices.PHOENIX_PAGING_NEW_SCAN_START_ROWKEY,
+ prevScanStartRowKey);
+ scan.setAttribute(
+
QueryServices.PHOENIX_PAGING_NEW_SCAN_START_ROWKEY_INCLUDE,
+ Bytes.toBytes(prevScanIncludeStartRowKey));
Review Comment:
OK, I got it. The first condition is true when we haven't returned any valid
rows yet.
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