Github user wuchong commented on a diff in the pull request:
https://github.com/apache/flink/pull/4266#discussion_r127153991
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/join/ProcTimeWindowInnerJoin.scala
---
@@ -0,0 +1,326 @@
+/*
+ * 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.join
+
+import java.util
+import java.util.{List => JList}
+
+import org.apache.flink.api.common.functions.FlatJoinFunction
+import org.apache.flink.api.common.state._
+import org.apache.flink.api.common.typeinfo.{BasicTypeInfo,
TypeInformation}
+import org.apache.flink.api.java.typeutils.ListTypeInfo
+import org.apache.flink.configuration.Configuration
+import org.apache.flink.streaming.api.functions.co.CoProcessFunction
+import org.apache.flink.table.codegen.Compiler
+import org.apache.flink.table.runtime.CRowWrappingCollector
+import org.apache.flink.table.runtime.types.CRow
+import org.apache.flink.types.Row
+import org.apache.flink.util.Collector
+import org.slf4j.LoggerFactory
+
+/**
+ * A CoProcessFunction to support stream join stream, currently just
support inner-join
+ *
+ * @param leftLowerBound
+ * the left stream lower bound, and -leftLowerBound is the right
stream upper bound
+ * @param leftUpperBound
+ * the left stream upper bound, and -leftUpperBound is the right
stream lower bound
+ * @param element1Type the input type of left stream
+ * @param element2Type the input type of right stream
+ * @param genJoinFuncName the function code of other non-equi condition
+ * @param genJoinFuncCode the function name of other non-equi condition
+ *
+ */
+class ProcTimeWindowInnerJoin(
+ private val leftLowerBound: Long,
+ private val leftUpperBound: Long,
+ private val element1Type: TypeInformation[Row],
+ private val element2Type: TypeInformation[Row],
+ private val genJoinFuncName: String,
+ private val genJoinFuncCode: String)
+ extends CoProcessFunction[CRow, CRow, CRow]
+ with Compiler[FlatJoinFunction[Row, Row, Row]]{
+
+ private var cRowWrapper: CRowWrappingCollector = _
+
+ /** other condition function **/
+ private var joinFunction: FlatJoinFunction[Row, Row, Row] = _
+
+ /** tmp list to store expired records **/
+ private var listToRemove: JList[Long] = _
+
+ /** state to hold left stream element **/
+ private var row1MapState: MapState[Long, JList[Row]] = _
+ /** state to hold right stream element **/
+ private var row2MapState: MapState[Long, JList[Row]] = _
+
+ /** state to record last timer of left stream, 0 means no timer **/
+ private var timerState1: ValueState[Long] = _
+ /** state to record last timer of right stream, 0 means no timer **/
+ private var timerState2: ValueState[Long] = _
+
+ private val leftStreamWinSize: Long = if (leftLowerBound < 0)
-leftLowerBound else 0
+ private val rightStreamWinSize: Long = if (leftUpperBound > 0)
leftUpperBound else 0
+
+ val LOG = LoggerFactory.getLogger(this.getClass)
+
+ override def open(config: Configuration) {
+ LOG.debug(s"Compiling JoinFunction: $genJoinFuncName \n\n " +
+ s"Code:\n$genJoinFuncCode")
+ val clazz = compile(
+ getRuntimeContext.getUserCodeClassLoader,
+ genJoinFuncName,
+ genJoinFuncCode)
+ LOG.debug("Instantiating JoinFunction.")
+ joinFunction = clazz.newInstance()
+
+ listToRemove = new util.ArrayList[Long]()
+ cRowWrapper = new CRowWrappingCollector()
+ cRowWrapper.setChange(true)
+
+ // initialize row state
+ val rowListTypeInfo1: TypeInformation[JList[Row]] = new
ListTypeInfo[Row](element1Type)
+ val mapStateDescriptor1: MapStateDescriptor[Long, JList[Row]] =
+ new MapStateDescriptor[Long, JList[Row]]("row1mapstate",
+ BasicTypeInfo.LONG_TYPE_INFO.asInstanceOf[TypeInformation[Long]],
rowListTypeInfo1)
+ row1MapState = getRuntimeContext.getMapState(mapStateDescriptor1)
+
+ val rowListTypeInfo2: TypeInformation[JList[Row]] = new
ListTypeInfo[Row](element2Type)
+ val mapStateDescriptor2: MapStateDescriptor[Long, JList[Row]] =
+ new MapStateDescriptor[Long, JList[Row]]("row2mapstate",
+ BasicTypeInfo.LONG_TYPE_INFO.asInstanceOf[TypeInformation[Long]],
rowListTypeInfo2)
+ row2MapState = getRuntimeContext.getMapState(mapStateDescriptor2)
+
+ // initialize timer state
+ val valueStateDescriptor1: ValueStateDescriptor[Long] =
+ new ValueStateDescriptor[Long]("timervaluestate1", classOf[Long])
+ timerState1 = getRuntimeContext.getState(valueStateDescriptor1)
+
+ val valueStateDescriptor2: ValueStateDescriptor[Long] =
+ new ValueStateDescriptor[Long]("timervaluestate2", classOf[Long])
+ timerState2 = getRuntimeContext.getState(valueStateDescriptor2)
+ }
+
+ /**
+ * Process left stream records
+ *
+ * @param valueC The input value.
+ * @param ctx The ctx to register timer or get current time
+ * @param out The collector for returning result values.
+ *
+ */
+ override def processElement1(
+ valueC: CRow,
+ ctx: CoProcessFunction[CRow, CRow, CRow]#Context,
+ out: Collector[CRow]): Unit = {
+
+ processElement(
+ valueC,
+ ctx,
+ out,
+ leftStreamWinSize,
+ timerState1,
+ row1MapState,
+ row2MapState,
+ -leftUpperBound, // right stream lower
+ -leftLowerBound, // right stream upper
+ true
+ )
+ }
+
+ /**
+ * Process right stream records
+ *
+ * @param valueC The input value.
+ * @param ctx The ctx to register timer or get current time
+ * @param out The collector for returning result values.
+ *
+ */
+ override def processElement2(
+ valueC: CRow,
+ ctx: CoProcessFunction[CRow, CRow, CRow]#Context,
+ out: Collector[CRow]): Unit = {
+
+ processElement(
+ valueC,
+ ctx,
+ out,
+ rightStreamWinSize,
+ timerState2,
+ row2MapState,
+ row1MapState,
+ leftLowerBound, // left stream upper
+ leftUpperBound, // left stream upper
+ false
+ )
+ }
+
+ /**
+ * Called when a processing timer trigger.
+ * Expire left/right records which earlier than current time -
windowsize.
+ *
+ * @param timestamp The timestamp of the firing timer.
+ * @param ctx The ctx to register timer or get current time
+ * @param out The collector for returning result values.
+ */
+ override def onTimer(
+ timestamp: Long,
+ ctx: CoProcessFunction[CRow, CRow, CRow]#OnTimerContext,
+ out: Collector[CRow]): Unit = {
+
+ if (timerState1.value == timestamp) {
+ expireOutTimeRow(
+ timestamp,
+ leftStreamWinSize,
+ row1MapState,
+ timerState1,
+ ctx
+ )
+ }
+
+ if (timerState2.value == timestamp) {
+ expireOutTimeRow(
+ timestamp,
+ rightStreamWinSize,
+ row2MapState,
+ timerState2,
+ ctx
+ )
+ }
+ }
+
+ /**
+ * Puts an element from the input stream into state and search the
other state to
+ * output records meet the condition, and registers a timer for the
current record
+ * if there is no timer at present.
+ */
+ private def processElement(
+ valueC: CRow,
+ ctx: CoProcessFunction[CRow, CRow, CRow]#Context,
+ out: Collector[CRow],
+ winSize: Long,
+ timerState: ValueState[Long],
+ rowMapState: MapState[Long, JList[Row]],
+ oppoRowMapState: MapState[Long, JList[Row]],
+ oppoLowerBound: Long,
+ oppoUpperBound: Long,
+ isLeft: Boolean): Unit = {
+
+ cRowWrapper.out = out
+
+ val value = valueC.row
+
+ val curProcessTime = ctx.timerService.currentProcessingTime
+ val oppoLowerTime = curProcessTime + oppoLowerBound
+ val oppoUpperTime = curProcessTime + oppoUpperBound
+
+ // only when windowsize != 0, we need to store the element
+ if (winSize != 0) {
--- End diff --
I'm not sure about this. For example, `a.proctime between b.proctime - 5
and b.proctime`. In this case, we will buffer stream `a` for a window size 5,
but will not buffer stream `b` because the right window size is 0.
Suppose the input elements are [a1, 1], [a2, 2], [b1, 5], [a3, 5]. The
first field in the tuple indicates which stream it belongs to. The seconds
field in the tuple is the processing timestamp. The expected result should be
`a1, b1`, `a2, b1`, `a3, b1`. But the actual result misses `a3, b1`. Because we
didn't buffer the elements from `b` stream.
So I think, even if the window size is 0, we still need to store the
elements. Of course, we will register a `curTime +1` timer to clean the states.
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