[jira] [Updated] (PHOENIX-2989) Allow DistinctPrefixFilter optimization when HAVING clause only reference COUNT(DISTINCT)

["Thomas D'Silva (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PHOENIX-2989?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thomas D'Silva updated PHOENIX-2989:
------------------------------------
    Fix Version/s:     (was: 4.15.0)

> Allow DistinctPrefixFilter optimization when HAVING clause only reference COUNT(DISTINCT)
> -----------------------------------------------------------------------------------------
>
>                 Key: PHOENIX-2989
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2989
>             Project: Phoenix
>          Issue Type: Sub-task
>            Reporter: James Taylor
>            Priority: Major
>         Attachments: 2989-orderby-v2.txt, 2989-orderby-v3.txt, 2989-orderby.txt
>
>
> The DistinctPrefixFilter optimization can still be used if a HAVING clause only references COUNT(DISTINCT) expressions. One way to detect this is to collect a Set<ParseNode> using a visitor for the SELECT and HAVING which only collects COUNT(DISTINCT) expressions. This set will then be used as the GROUP BY nodes if there's no existing GROUP BY.
> The check for whether or not to add the filter can then change to something like this:
> {code}
>     if (... &&
>     ( context.getAggregationManager().isEmpty() ||
>       ( plan.getGroupBy().isUngroupedAggregate() &&
>         plan.getGroupBy().getKeyExpressions().size() ==  
>         context.getAggregationManager().getAggregators().getAggregatorCount() ) ) )
> {code}
> That way, it'll only add the filter if all expressions pulled in as a GROUP BY expression (only the count distinct ones) account for all of the aggregators.



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