[
https://issues.apache.org/jira/browse/CALCITE-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Haisheng Yuan resolved CALCITE-1172.
------------------------------------
Resolution: Fixed
Fix Version/s: 1.20.0
Pushed to master, thanks for the review, [~vgarg], [~zhztheplayer]!
> Add rule to flatten two Aggregate operators into one
> ----------------------------------------------------
>
> Key: CALCITE-1172
> URL: https://issues.apache.org/jira/browse/CALCITE-1172
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.20.0
>
> Time Spent: 3h 50m
> Remaining Estimate: 0h
>
> If there is an Aggregate on top of an Aggregate, and the top aggregate's
> group key is a subset of the lower aggregate's group key, and the aggregates
> are expansions of rollups, then a rule would convert into a single aggregate.
> For example, SUM of SUM becomes SUM; SUM of COUNT becomes COUNT; MAX of MAX
> becomes MAX; MIN of MIN becomes MIN. AVG of AVG would not match, nor would
> COUNT of COUNT.
> The rule would convert
> {noformat}
> Aggregate({x}, SUM(c1), MIN(c2), MAX(c3))
> Aggregate({x, y}, SUM(c1), MIN(c2), MAX(c3))
> R
> {noformat}
> into
> {noformat}
> Aggregate({x}, SUM(c1), MIN(c2), MAX(c3))
> R
> {noformat}
> The rule would not work if there was anything between the two {{Aggregate}}
> operators.
> The implementation would use {{SqlSplittableAggFunction}} to deduce rollups,
> and in fact would be practically the converse of
> {{AggregateExchangeTransposeRule}} proposed in CALCITE-907.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
