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ASF GitHub Bot commented on FLINK-4937: --------------------------------------- Github user sunjincheng121 commented on a diff in the pull request: https://github.com/apache/flink/pull/2792#discussion_r89247312 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/runtime/aggregate/AggregateUtil.scala --- @@ -39,66 +45,69 @@ object AggregateUtil { type JavaList[T] = java.util.List[T] /** - * Create Flink operator functions for aggregates. It includes 2 implementations of Flink - * operator functions: - * [[org.apache.flink.api.common.functions.MapFunction]] and - * [[org.apache.flink.api.common.functions.GroupReduceFunction]](if it's partial aggregate, - * should also implement [[org.apache.flink.api.common.functions.CombineFunction]] as well). - * The output of [[org.apache.flink.api.common.functions.MapFunction]] contains the - * intermediate aggregate values of all aggregate function, it's stored in Row by the following - * format: - * - * {{{ - * avg(x) aggOffsetInRow = 2 count(z) aggOffsetInRow = 5 - * | | - * v v - * +---------+---------+--------+--------+--------+--------+ - * |groupKey1|groupKey2| sum1 | count1 | sum2 | count2 | - * +---------+---------+--------+--------+--------+--------+ - * ^ - * | - * sum(y) aggOffsetInRow = 4 - * }}} - * - */ - def createOperatorFunctionsForAggregates( - namedAggregates: Seq[CalcitePair[AggregateCall, String]], - inputType: RelDataType, - outputType: RelDataType, - groupings: Array[Int]) - : (MapFunction[Any, Row], RichGroupReduceFunction[Row, Row]) = { - - val aggregateFunctionsAndFieldIndexes = - transformToAggregateFunctions(namedAggregates.map(_.getKey), inputType, groupings.length) - // store the aggregate fields of each aggregate function, by the same order of aggregates. - val aggFieldIndexes = aggregateFunctionsAndFieldIndexes._1 - val aggregates = aggregateFunctionsAndFieldIndexes._2 + * Create prepare MapFunction for aggregates. + * The output of [[org.apache.flink.api.common.functions.MapFunction]] contains the + * intermediate aggregate values of all aggregate function, it's stored in Row by the following + * format: + * + * {{{ + * avg(x) aggOffsetInRow = 2 count(z) aggOffsetInRow = 5 + * | | + * v v + * +---------+---------+--------+--------+--------+--------+ + * |groupKey1|groupKey2| sum1 | count1 | sum2 | count2 | + * +---------+---------+--------+--------+--------+--------+ + * ^ + * | + * sum(y) aggOffsetInRow = 4 + * }}} + * + */ + private[flink] def createPrepareMapFunction( + aggregates: Array[Aggregate[_ <: Any]], --- End diff -- Cool,I think use Calcite's namedAggregates is a good idea. > Add incremental group window aggregation for streaming Table API > ---------------------------------------------------------------- > > Key: FLINK-4937 > URL: https://issues.apache.org/jira/browse/FLINK-4937 > Project: Flink > Issue Type: Sub-task > Components: Table API & SQL > Affects Versions: 1.2.0 > Reporter: Fabian Hueske > Assignee: sunjincheng > > Group-window aggregates for streaming tables are currently not done in an > incremental fashion. This means that the window collects all records and > performs the aggregation when the window is closed instead of eagerly > updating a partial aggregate for every added record. Since records are > buffered, non-incremental aggregation requires more storage space than > incremental aggregation. > The DataStream API which is used under the hood of the streaming Table API > features [incremental > aggregation|https://ci.apache.org/projects/flink/flink-docs-release-1.2/dev/windows.html#windowfunction-with-incremental-aggregation] > using a {{ReduceFunction}}. > We should add support for incremental aggregation in group-windows. > This is a follow-up task of FLINK-4691. -- This message was sent by Atlassian JIRA (v6.3.4#6332)