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https://issues.apache.org/jira/browse/PHOENIX-7106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17806149#comment-17806149
]
ASF GitHub Bot commented on PHOENIX-7106:
-----------------------------------------
kadirozde commented on code in PR #1736:
URL: https://github.com/apache/phoenix/pull/1736#discussion_r1450778626
##########
phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/UncoveredIndexRegionScanner.java:
##########
@@ -404,4 +421,37 @@ public boolean next(List<Cell> result) throws IOException {
region.closeRegionOperation();
}
}
+
+ /**
+ * Add dummy cell to the result list based on either the previous rowkey
returned to the
+ * client or the start rowkey and start rowkey include params.
+ *
+ * @param result result to add the dummy cell to.
+ * @param initStartRowKey scan start rowkey.
+ * @param includeInitStartRowKey scan start rowkey included.
+ * @param scan scan object.
+ */
+ private void updateDummyWithPrevRowKey(List<Cell> result, byte[]
initStartRowKey,
+ boolean includeInitStartRowKey,
Scan scan) {
+ result.clear();
+ if (previousResultRowKey != null) {
+ getDummyResult(previousResultRowKey, result);
+ } else {
+ if (includeInitStartRowKey && initStartRowKey.length > 0) {
+ byte[] prevKey;
+ if (Bytes.compareTo(initStartRowKey, initStartRowKey.length -
1,
+ 1, Bytes.toBytesBinary("\\x00"), 0, 1) == 0) {
+ prevKey = new byte[initStartRowKey.length - 1];
+ System.arraycopy(initStartRowKey, 0, prevKey, 0,
prevKey.length);
+ } else {
+ prevKey =
ByteUtil.previousKeyWithLength(ByteUtil.concat(initStartRowKey,
+ new byte[10]), initStartRowKey.length + 10);
Review Comment:
Padding 10 zero bytes needs some explanation here.
> 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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