Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3700#discussion_r110481364
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/aggregate/ProcTimeUnboundedSortProcessFunction.scala
---
@@ -0,0 +1,139 @@
+/*
+ * 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 org.apache.flink.api.common.state.{ ListState, ListStateDescriptor }
+import org.apache.flink.api.java.typeutils.RowTypeInfo
+import org.apache.flink.configuration.Configuration
+import org.apache.flink.runtime.state.{ FunctionInitializationContext,
FunctionSnapshotContext }
+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 }
+import org.apache.flink.api.common.state.ValueState
+import org.apache.flink.api.common.state.ValueStateDescriptor
+import scala.util.control.Breaks._
+import org.apache.flink.api.java.tuple.{ Tuple2 => JTuple2 }
+import org.apache.flink.api.common.state.MapState
+import org.apache.flink.api.common.state.MapStateDescriptor
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.java.typeutils.ListTypeInfo
+import java.util.{ ArrayList, LinkedList, List => JList }
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo
+import
org.apache.flink.table.runtime.aggregate.MultiOutputAggregateFunction
+
+/**
+ * Process Function used for the aggregate in bounded proc-time OVER window
+ * [[org.apache.flink.streaming.api.datastream.DataStream]]
+ *
+ * @param aggregates the
[[org.apache.flink.table.functions.aggfunctions.SortAggFunction]]
+ * used for this sort aggregation
+ * @param fieldCount Is used to indicate fields in the current element to
forward
+ * @param aggType It is used to mark the Aggregate type
+ */
+class ProcTimeUnboundedSortProcessFunction(
+ private val aggregates: MultiOutputAggregateFunction[_],
--- End diff --
I don't think the sorting should be done with an aggregation function. An
aggregation function returns a single value and is IMO not the right tool to
sort data.
I would make the design similar to the one you have, but instead of using
an accumulator, you can use a `ListState` to append new records. When the timer
fires, you collect all data for the millisecond, and sort with Java's regular
collections sort with a `Comparator<Row>` that wraps `TypeComparators` for the
secondary sort fields.
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