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From: fhueske <git@git.apache.org>
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Subject: [GitHub] flink pull request #4625: [FLINK-6233] [table] Support time-bounded stream i...
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Message-Id: <20171004193536.7CB84F5BD1@git1-us-west.apache.org>
Date: Wed,  4 Oct 2017 19:35:36 +0000 (UTC)
archived-at: Wed, 04 Oct 2017 19:35:41 -0000

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

    https://github.com/apache/flink/pull/4625#discussion_r142697408
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/join/TimeBoundedStreamInnerJoin.scala ---
    @@ -0,0 +1,410 @@
    +/*
    + * 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.{ArrayList, List => JList}
    +
    +import org.apache.flink.api.common.functions.FlatJoinFunction
    +import org.apache.flink.api.common.state._
    +import org.apache.flink.api.common.typeinfo.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.api.Types
    +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.table.util.Logging
    +import org.apache.flink.types.Row
    +import org.apache.flink.util.Collector
    +
    +/**
    +  * A CoProcessFunction to execute time-bounded stream inner-join.
    +  * Two kinds of time criteria:
    +  * "L.time between R.time + X and R.time + Y" or "R.time between L.time - Y and L.time - X".
    +  *
    +  * @param leftLowerBound  the lower bound for the left stream (X in the criteria)
    +  * @param leftUpperBound  the upper bound for the left stream (Y in the criteria)
    +  * @param allowedLateness the lateness allowed for the two streams
    +  * @param leftType        the input type of left stream
    +  * @param rightType       the input type of right stream
    +  * @param genJoinFuncName the function code of other non-equi conditions
    +  * @param genJoinFuncCode the function name of other non-equi conditions
    +  *
    +  */
    +abstract class TimeBoundedStreamInnerJoin(
    +    private val leftLowerBound: Long,
    +    private val leftUpperBound: Long,
    +    private val allowedLateness: Long,
    +    private val leftType: TypeInformation[Row],
    +    private val rightType: TypeInformation[Row],
    +    private val genJoinFuncName: String,
    +    private val genJoinFuncCode: String,
    +    private val leftTimeIdx: Int,
    +    private val rightTimeIdx: Int)
    +    extends CoProcessFunction[CRow, CRow, CRow]
    +    with Compiler[FlatJoinFunction[Row, Row, Row]]
    +    with Logging {
    +
    +  private var cRowWrapper: CRowWrappingCollector = _
    +
    +  // the join function for other conditions
    +  private var joinFunction: FlatJoinFunction[Row, Row, Row] = _
    +
    +  // cache to store rows from the left stream
    +  private var leftCache: MapState[Long, JList[Row]] = _
    +  // cache to store rows from the right stream
    +  private var rightCache: MapState[Long, JList[Row]] = _
    +
    +  // state to record the timer on the left stream. 0 means no timer set
    +  private var leftTimerState: ValueState[Long] = _
    +  // state to record the timer on the right stream. 0 means no timer set
    +  private var rightTimerState: ValueState[Long] = _
    +
    +  private val leftRelativeSize: Long = -leftLowerBound
    +  private val rightRelativeSize: Long = leftUpperBound
    +
    +  private var leftExpirationTime: Long = 0L;
    +  private var rightExpirationTime: Long = 0L;
    +
    +  protected var leftOperatorTime: Long = 0L
    +  protected var rightOperatorTime: Long = 0L
    +
    +
    +  // for delayed cleanup
    +  private val cleanupDelay = (leftRelativeSize + rightRelativeSize) / 2
    +
    +  if (allowedLateness < 0) {
    +    throw new IllegalArgumentException("The allowed lateness must be non-negative.")
    +  }
    +
    +  /**
    +    * Get the maximum interval between receiving a row and emitting it (as part of a joined result).
    +    * Only reasonable for row time join.
    +    *
    +    * @return the maximum delay for the outputs
    +    */
    +  def getMaxOutputDelay: Long = Math.max(leftRelativeSize, rightRelativeSize) + allowedLateness
    +
    +  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()
    +
    +    cRowWrapper = new CRowWrappingCollector()
    +    cRowWrapper.setChange(true)
    +
    +    // Initialize the data caches.
    +    val leftListTypeInfo: TypeInformation[JList[Row]] = new ListTypeInfo[Row](leftType)
    +    val leftStateDescriptor: MapStateDescriptor[Long, JList[Row]] =
    +      new MapStateDescriptor[Long, JList[Row]](
    +        "InnerJoinLeftCache",
    +        Types.LONG.asInstanceOf[TypeInformation[Long]],
    +        leftListTypeInfo)
    +    leftCache = getRuntimeContext.getMapState(leftStateDescriptor)
    +
    +    val rightListTypeInfo: TypeInformation[JList[Row]] = new ListTypeInfo[Row](rightType)
    +    val rightStateDescriptor: MapStateDescriptor[Long, JList[Row]] =
    +      new MapStateDescriptor[Long, JList[Row]](
    +        "InnerJoinRightCache",
    +        Types.LONG.asInstanceOf[TypeInformation[Long]],
    +        rightListTypeInfo)
    +    rightCache = getRuntimeContext.getMapState(rightStateDescriptor)
    +
    +    // Initialize the timer states.
    +    val leftTimerStateDesc: ValueStateDescriptor[Long] =
    +      new ValueStateDescriptor[Long]("InnerJoinLeftTimerState", classOf[Long])
    +    leftTimerState = getRuntimeContext.getState(leftTimerStateDesc)
    +
    +    val rightTimerStateDesc: ValueStateDescriptor[Long] =
    +      new ValueStateDescriptor[Long]("InnerJoinRightTimerState", classOf[Long])
    +    rightTimerState = getRuntimeContext.getState(rightTimerStateDesc)
    +  }
    +
    +  /**
    +    * Process rows from the left stream.
    +    */
    +  override def processElement1(
    +      cRowValue: CRow,
    +      ctx: CoProcessFunction[CRow, CRow, CRow]#Context,
    +      out: Collector[CRow]): Unit = {
    +    updateOperatorTime(ctx)
    +    val leftRow = cRowValue.row
    +    val timeForLeftRow: Long = getTimeForLeftStream(ctx, leftRow)
    +    val rightQualifiedLowerBound: Long = timeForLeftRow - rightRelativeSize
    +    val rightQualifiedUpperBound: Long = timeForLeftRow + leftRelativeSize
    +    cRowWrapper.out = out
    +
    +    if (rightOperatorTime < rightQualifiedUpperBound) {
    --- End diff --
    
    Add comment for the branch of the condition like "Operator time of right stream has not exceeded the upper window bound of the current record. We must expect records from the right stream that join with the current record."


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