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https://issues.apache.org/jira/browse/PHOENIX-2722?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15213912#comment-15213912
]
ASF GitHub Bot commented on PHOENIX-2722:
-----------------------------------------
Github user ankitsinghal commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/154#discussion_r57551094
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/compile/SubselectRewriter.java ---
@@ -202,14 +204,30 @@ private SelectStatement flatten(SelectStatement
select, SelectStatement subselec
}
}
}
-
+ OffsetNode offset = select.getOffset();
+ if (offset != null) {
+ if (offsetRewrite == null) {
+ offsetRewrite = offset;
+ } else {
+ Integer offsetValue = OffsetCompiler.compile(null, select);
+ Integer offsetValueSubselect =
OffsetCompiler.compile(null, subselect);
+ if (offsetValue != null && offsetValueSubselect != null) {
+ offsetRewrite = offsetValue < offsetValueSubselect ?
offset : offsetRewrite;
+ } else {
+ return select;
+ }
+ }
+ }
+
--- End diff --
Thanks for pointing out. I thought a little and have updated the logic to
if (offsetRewrite != null || (limitRewrite != null & offset != null)) {
return select;
} else {
offsetRewrite = offset;
}
Let me know if any optimization is possible.
> support mysql "limit,offset" clauses
> -------------------------------------
>
> Key: PHOENIX-2722
> URL: https://issues.apache.org/jira/browse/PHOENIX-2722
> Project: Phoenix
> Issue Type: New Feature
> Reporter: Ankit Singhal
> Assignee: Ankit Singhal
> Priority: Minor
> Attachments: PHOENIX-2722.patch, PHOENIX-2722_formatted.patch
>
>
> For serial query(query with “serial" hint or “limit" without "order by”), we
> can limit each scan(using page filter) to “limit+offset” instead of limit
> earlier.
> And then, for all queries, we can forward the relevant client iterators to
> the offset provided and then return the result.
> syntax
> {code}
> [ LIMIT { count } ]
> [ OFFSET start [ ROW | ROWS ] ]
> [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ]
> {code}
> Some new keywords(OFFSET,FETCH,ROW, ROWS,ONLY) are getting introduced so
> users might need to see that they are not using them as column name or
> something.
> WDYT, [~jamestaylor]
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