[GitHub] [druid] clintropolis commented on a change in pull request #11014: Enable multiple distinct aggregators in same query

[GitBox <gi...@apache.org>]

clintropolis commented on a change in pull request #11014:
URL: https://github.com/apache/druid/pull/11014#discussion_r607363683



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File path: docs/configuration/index.md
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@@ -1675,6 +1675,7 @@ The Druid SQL server is configured through the following properties on the Broke
 |`druid.sql.planner.maxTopNLimit`|Maximum threshold for a [TopN query](../querying/topnquery.md). Higher limits will be planned as [GroupBy queries](../querying/groupbyquery.md) instead.|100000|
 |`druid.sql.planner.metadataRefreshPeriod`|Throttle for metadata refreshes.|PT1M|
 |`druid.sql.planner.useApproximateCountDistinct`|Whether to use an approximate cardinality algorithm for `COUNT(DISTINCT foo)`.|true|
+|`druid.sql.planner.useGroupingSetForExactDistinct`|Only relevant when `useApproximateCountDistinct` is disabled. If set to true, exact distinct queries are re-written using grouping sets. Otherwise, exact distinct queries are re-written using joins. This should be set to true for group by query with multiple exact distinct aggregations. This flag can be overridden per query.|false|

Review comment:
       I think it would be ok if we could leave off by default for next release, and maybe consider turning on in the release after




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