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https://issues.apache.org/jira/browse/PHOENIX-7106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17806162#comment-17806162
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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_r1450814882
##########
phoenix-core-client/src/main/java/org/apache/phoenix/iterate/OffsetResultIterator.java:
##########
@@ -32,32 +34,49 @@
*/
public class OffsetResultIterator extends DelegateResultIterator {
private int rowCount;
- private int offset;
+ private final int offset;
+ private Tuple lastScannedTuple;
private long pageSizeMs = Long.MAX_VALUE;
+ private boolean isIncompatibleClient = false;
public OffsetResultIterator(ResultIterator delegate, Integer offset) {
super(delegate);
this.offset = offset == null ? -1 : offset;
+ this.lastScannedTuple = null;
}
- public OffsetResultIterator(ResultIterator delegate, Integer offset, long
pageSizeMs) {
+ public OffsetResultIterator(ResultIterator delegate, Integer offset, long
pageSizeMs,
+ boolean isIncompatibleClient) {
this(delegate, offset);
this.pageSizeMs = pageSizeMs;
+ this.isIncompatibleClient = isIncompatibleClient;
}
+
@Override
public Tuple next() throws SQLException {
+ long startTime = EnvironmentEdgeManager.currentTimeMillis();
while (rowCount < offset) {
Tuple tuple = super.next();
- if (tuple == null) { return null; }
+ if (tuple == null) {
+ return null;
+ }
if (tuple.size() == 0 || isDummy(tuple)) {
// while rowCount < offset absorb the dummy and call next on
the underlying scanner
continue;
}
rowCount++;
- // no page timeout check at this level because we cannot correctly
resume
- // scans for OFFSET queries until the offset is reached
+ lastScannedTuple = tuple;
+ if (!isIncompatibleClient) {
+ if (EnvironmentEdgeManager.currentTimeMillis() - startTime >=
pageSizeMs) {
Review Comment:
Hmm that's also good point, let me check what happens to `_RowOffset`, i
think scan attributes are preserved because when scanner is reset, on the same
scan object, start rowkey is changed so the scan attributes should remain the
same but let me spend sometime to confirm this.
> 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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