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https://issues.apache.org/jira/browse/CALCITE-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde updated CALCITE-1172:
---------------------------------
Description:
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.
was:
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.
> 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
> Assignee: Julian Hyde
>
> 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.
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