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https://issues.apache.org/jira/browse/FLINK-5990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15938626#comment-15938626
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ASF GitHub Bot commented on FLINK-5990:
---------------------------------------

Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3585#discussion_r107674994
  
    --- Diff: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/aggregate/RowsClauseBoundedOverProcessFunction.scala
 ---
    @@ -0,0 +1,206 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +package org.apache.flink.table.runtime.aggregate
    +
    +import java.util.{ArrayList, List => JList}
    +
    +import org.apache.flink.api.common.state._
    +import org.apache.flink.api.java.typeutils.RowTypeInfo
    +import org.apache.flink.configuration.Configuration
    +import org.apache.flink.streaming.api.functions.ProcessFunction
    +import org.apache.flink.table.functions.{Accumulator, AggregateFunction}
    +import org.apache.flink.types.Row
    +import org.apache.flink.util.{Collector, Preconditions}
    +
    +/**
    +  * Process Function for ROWS clause event-time bounded OVER window
    +  *
    +  * @param aggregates           the list of all 
[[org.apache.flink.table.functions.AggregateFunction]]
    +  *                             used for this aggregation
    +  * @param aggFields            the position (in the input Row) of the 
input value for each aggregate
    +  * @param forwardedFieldCount  the count of forwarded fields.
    +  * @param aggregationStateType the row type info of aggregation
    +  * @param precedingOffset      the preceding offset
    +  */
    +class RowsClauseBoundedOverProcessFunction(
    +    private val aggregates: Array[AggregateFunction[_]],
    +    private val aggFields: Array[Int],
    +    private val forwardedFieldCount: Int,
    +    private val aggregationStateType: RowTypeInfo,
    +    private val precedingOffset: Long)
    +  extends ProcessFunction[Row, Row] {
    +
    +  Preconditions.checkNotNull(aggregates)
    +  Preconditions.checkNotNull(aggFields)
    +  Preconditions.checkArgument(aggregates.length == aggFields.length)
    +  Preconditions.checkNotNull(forwardedFieldCount)
    +  Preconditions.checkNotNull(aggregationStateType)
    +  Preconditions.checkNotNull(precedingOffset)
    +
    +  private var output: Row = _
    +
    +  // the state which keeps the last triggering timestamp
    +  private var lastTriggeringTsState: ValueState[Long] = _
    +
    +  // the state which keeps the count of data
    +  private var dataCountState: ValueState[Long] = null
    +
    +  // the state which used to materialize the accumulator for incremental 
calculation
    +  private var accumulatorState: ValueState[Row] = _
    +
    +  // the state which keeps all the data that are not expired.
    +  // The first element (as the mapState key) of the tuple is the time 
stamp. Per each time stamp,
    +  // the second element of tuple is a list that contains the entire data 
of all the rows belonging
    +  // to this time stamp.
    +  private var dataState: MapState[Long, JList[Row]] = _
    +
    +  override def open(config: Configuration) {
    +
    +    output = new Row(forwardedFieldCount + aggregates.length)
    +
    +
    +    val lastTriggeringTsDescriptor: ValueStateDescriptor[Long] =
    +      new ValueStateDescriptor[Long]("lastTriggeringTsState", 
classOf[Long])
    +    lastTriggeringTsState = 
getRuntimeContext.getState(lastTriggeringTsDescriptor)
    +
    +    val dataCountStateDescriptor =
    +      new ValueStateDescriptor[Long]("dataCountState", classOf[Long])
    +    dataCountState = getRuntimeContext.getState(dataCountStateDescriptor)
    +
    +    val accumulatorStateDescriptor =
    +      new ValueStateDescriptor[Row]("accumulatorState", 
aggregationStateType)
    +    accumulatorState = 
getRuntimeContext.getState(accumulatorStateDescriptor)
    +
    +    val mapStateDescriptor: MapStateDescriptor[Long, JList[Row]] =
    +      new MapStateDescriptor[Long, JList[Row]](
    +        "dataState",
    +        classOf[Long],
    +        classOf[JList[Row]])
    --- End diff --
    
    We should use the correct RowTypeInfo of the input type here. Otherwise, 
we'll have a less efficient GenericType and serialize with Kryo.


> Add [partitioned] event time OVER ROWS BETWEEN x PRECEDING aggregation to SQL
> -----------------------------------------------------------------------------
>
>                 Key: FLINK-5990
>                 URL: https://issues.apache.org/jira/browse/FLINK-5990
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: sunjincheng
>            Assignee: sunjincheng
>
> The goal of this issue is to add support for OVER ROWS aggregations on event 
> time streams to the SQL interface.
> Queries similar to the following should be supported:
> {code}
> SELECT 
>   a, 
>   SUM(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND 
> CURRENT ROW) AS sumB,
>   MIN(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS BETWEEN 2 PRECEDING AND 
> CURRENT ROW) AS minB
> FROM myStream
> {code}
> The following restrictions should initially apply:
> - All OVER clauses in the same SELECT clause must be exactly the same.
> - The PARTITION BY clause is required
> - The ORDER BY clause may only have rowTime() as parameter. rowTime() is a 
> parameterless scalar function that just indicates event time mode.
> - UNBOUNDED PRECEDING is not supported (see FLINK-5803)
> - FOLLOWING is not supported.
> The restrictions will be resolved in follow up issues. If we find that some 
> of the restrictions are trivial to address, we can add the functionality in 
> this issue as well.
> This issue includes:
> - Design of the DataStream operator to compute OVER ROW aggregates
> - Translation from Calcite's RelNode representation (LogicalProject with 
> RexOver expression).



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