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Cheng Hao authored
Add support for `GROUPING SETS`, `ROLLUP`, `CUBE` and the the virtual column `GROUPING__ID`. More details on how to use the `GROUPING SETS" can be found at: https://cwiki.apache.org/confluence/display/Hive/Enhanced+Aggregation,+Cube,+Grouping+and+Rollup https://issues.apache.org/jira/secure/attachment/12676811/grouping_set.pdf The generic idea of the implementations are : 1 Replace the `ROLLUP`, `CUBE` with `GROUPING SETS` 2 Explode each of the input row, and then feed them to `Aggregate` * Each grouping set are represented as the bit mask for the `GroupBy Expression List`, for each bit, `1` means the expression is selected, otherwise `0` (left is the lower bit, and right is the higher bit in the `GroupBy Expression List`) * Several of projections are constructed according to the grouping sets, and within each projection(Seq[Expression), we replace those expressions with `Literal(null)` if it's not selected in the grouping set (based on the bit mask) * Output Schema of `Explode` is `child.output :+ grouping__id` * GroupBy Expressions of `Aggregate` is `GroupBy Expression List :+ grouping__id` * Keep the `Aggregation expressions` the same for the `Aggregate` The expressions substitutions happen in Logic Plan analyzing, so we will benefit from the Logical Plan optimization (e.g. expression constant folding, and map side aggregation etc.), Only an `Explosive` operator added for Physical Plan, which will explode the rows according the pre-set projections. A known issue will be done in the follow up PR: * Optimization `ColumnPruning` is not supported yet for `Explosive` node. Author: Cheng Hao <hao.cheng@intel.com> Closes #1567 from chenghao-intel/grouping_sets and squashes the following commits: fe65fcc [Cheng Hao] Remove the extra space 3547056 [Cheng Hao] Add more doc and Simplify the Expand a7c869d [Cheng Hao] update code as feedbacks d23c672 [Cheng Hao] Add GroupingExpression to replace the Seq[Expression] 414b165 [Cheng Hao] revert the unnecessary changes ec276c6 [Cheng Hao] Support Rollup/Cube/GroupingSets
Cheng Hao authoredAdd support for `GROUPING SETS`, `ROLLUP`, `CUBE` and the the virtual column `GROUPING__ID`. More details on how to use the `GROUPING SETS" can be found at: https://cwiki.apache.org/confluence/display/Hive/Enhanced+Aggregation,+Cube,+Grouping+and+Rollup https://issues.apache.org/jira/secure/attachment/12676811/grouping_set.pdf The generic idea of the implementations are : 1 Replace the `ROLLUP`, `CUBE` with `GROUPING SETS` 2 Explode each of the input row, and then feed them to `Aggregate` * Each grouping set are represented as the bit mask for the `GroupBy Expression List`, for each bit, `1` means the expression is selected, otherwise `0` (left is the lower bit, and right is the higher bit in the `GroupBy Expression List`) * Several of projections are constructed according to the grouping sets, and within each projection(Seq[Expression), we replace those expressions with `Literal(null)` if it's not selected in the grouping set (based on the bit mask) * Output Schema of `Explode` is `child.output :+ grouping__id` * GroupBy Expressions of `Aggregate` is `GroupBy Expression List :+ grouping__id` * Keep the `Aggregation expressions` the same for the `Aggregate` The expressions substitutions happen in Logic Plan analyzing, so we will benefit from the Logical Plan optimization (e.g. expression constant folding, and map side aggregation etc.), Only an `Explosive` operator added for Physical Plan, which will explode the rows according the pre-set projections. A known issue will be done in the follow up PR: * Optimization `ColumnPruning` is not supported yet for `Explosive` node. Author: Cheng Hao <hao.cheng@intel.com> Closes #1567 from chenghao-intel/grouping_sets and squashes the following commits: fe65fcc [Cheng Hao] Remove the extra space 3547056 [Cheng Hao] Add more doc and Simplify the Expand a7c869d [Cheng Hao] update code as feedbacks d23c672 [Cheng Hao] Add GroupingExpression to replace the Seq[Expression] 414b165 [Cheng Hao] revert the unnecessary changes ec276c6 [Cheng Hao] Support Rollup/Cube/GroupingSets
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