[
https://issues.apache.org/jira/browse/PHOENIX-4964?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16645609#comment-16645609
]
Lars Hofhansl commented on PHOENIX-4964:
----------------------------------------
I tested a hack to make it work for LOCAL indexes and the performance gain is
dramatic as expected (100x faster in this case).
But the actual fix is a bit more involved, we only want to scan the index if
the index's sort order matches the ORDER BY exactly.
> ORDER BY does not use an index if the query is not fully covered
> ----------------------------------------------------------------
>
> Key: PHOENIX-4964
> URL: https://issues.apache.org/jira/browse/PHOENIX-4964
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Lars Hofhansl
> Priority: Minor
>
> I just noticed that a query like
> {{SELECT <column1> FROM <table> ORDER BY <column2> LIMIT <n>}}
> Does not use an index on <column2> if it does not also include <column1>.
> That seems too limited.
> I can see the code in QueryOptimizer.addPlan that rewrites the plan only when
> there's a WHERE clause, and then only for the WHERE clause.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
