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https://issues.apache.org/jira/browse/PHOENIX-291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gabriel Reid resolved PHOENIX-291.
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Resolution: Fixed
Bulk resolve of closed issues imported from GitHub. This status was reached by
first re-opening all closed imported issues and then resolving them in bulk.
> Use hint to overide skip scan/range scan determination
> ------------------------------------------------------
>
> Key: PHOENIX-291
> URL: https://issues.apache.org/jira/browse/PHOENIX-291
> Project: Phoenix
> Issue Type: Task
> Reporter: James Taylor
> Assignee: tonyhuang
> Labels: enhancement
>
> We currently always use a skip scan filter when we can. There are cases in
> which performance is better if a range scan would have been used. We should
> allow the user to specify a hint in the query to override this decision.
> The same is true of a range scan. There are time when we don't have a filter
> for the leading PK column, but do have one for the second PK column. In this
> case currently, a skip scan won't be done. However, depending on the
> cardinality of the first column, it would be better to do a skip scan.
> The SelectStatement already has a hintNode that is passed through the
> grammar. Let's introduce a couple of simple hints:
> SELECT /*+ range_scan */
> and
> SELECT /*+ skip_scan */
> These could be used to override the default behavior. These hints will not be
> as necessary once we have stats, but aren't a bad idea to have even then,
> since the table stats may get out of date too.
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