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https://issues.apache.org/jira/browse/FLINK-9715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16646603#comment-16646603
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ASF GitHub Bot commented on FLINK-9715:
---------------------------------------

hequn8128 commented on a change in pull request #6776: [FLINK-9715][table] 
Support temporal join with event time
URL: https://github.com/apache/flink/pull/6776#discussion_r224492754
 
 

 ##########
 File path: 
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/runtime/join/TemporalRowtimeJoin.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.lang.{Long => JLong}
+import java.util
+import java.util.Comparator
+
+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.runtime.state.{VoidNamespace, VoidNamespaceSerializer}
+import org.apache.flink.streaming.api.SimpleTimerService
+import org.apache.flink.streaming.api.operators._
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord
+import org.apache.flink.table.api.{StreamQueryConfig, TableException}
+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.typeutils.TypeCheckUtils._
+import org.apache.flink.table.util.Logging
+import org.apache.flink.types.Row
+
+import scala.collection.JavaConversions._
+
+/**
+  * This operator works by keeping on the state collection of probe and build 
records to process
+  * on next watermark. The idea is that between watermarks we are collecting 
those elements
+  * and once we are sure that there will be no updates we emit the correct 
result and clean up the
+  * state.
+  *
+  * Cleaning up the state drops all of the "old" values from the probe side, 
where "old" is defined
+  * as older then the current watermark. Build side is also cleaned up in the 
similar fashion,
+  * however we always keep at least one record - the latest one - even if it's 
past the last
+  * watermark.
+  *
+  * One more trick is how the emitting results and cleaning up is triggered. 
It is achieved
+  * by registering timers for the keys. We could register a timer for every 
probe and build
+  * side element's event time (when watermark exceeds this timer, that's when 
we are emitting and/or
+  * cleaning up the state). However this would cause huge number of registered 
timers. For example
+  * with following evenTimes of probe records accumulated: {1, 2, 5, 8, 9}, if 
we
+  * had received Watermark(10), it would trigger 5 separate timers for the 
same key. To avoid that
+  * we always keep only one single registered timer for any given key, 
registered for the minimal
+  * value. Upon triggering it, we process all records with event times older 
then or equal to
+  * currentWatermark.
+  */
+class TemporalRowtimeJoin(
+    leftType: TypeInformation[Row],
+    rightType: TypeInformation[Row],
+    genJoinFuncName: String,
+    genJoinFuncCode: String,
+    queryConfig: StreamQueryConfig,
+    leftTimeAttribute: Int,
+    rightTimeAttribute: Int)
+  extends AbstractStreamOperator[CRow]
+  with TwoInputStreamOperator[CRow, CRow, CRow]
+  with Triggerable[Any, VoidNamespace]
+  with Compiler[FlatJoinFunction[Row, Row, Row]]
+  with Logging {
+
+  validateEqualsHashCode("join", leftType)
+  validateEqualsHashCode("join", rightType)
+
+  private val NEXT_LEFT_INDEX_STATE_NAME = "next-index"
+  private val LEFT_STATE_NAME = "left"
+  private val RIGHT_STATE_NAME = "right"
+  private val REGISTERED_TIMER_STATE_NAME = "timer"
+  private val TIMERS_STATE_NAME = "timers"
+
+  private val rightRowtimeComparator = new 
RowtimeComparator(rightTimeAttribute)
+
+  /**
+    * Incremental index generator for `leftState`'s keys.
+    */
+  private var nextLeftIndex: ValueState[JLong] = _
+
+  /**
+    * Mapping from artificial row index (generated by `nextLeftIndex`) into 
the left side `Row`.
+    * We can not use List to accumulate Rows, because we need efficient 
deletes of the oldest rows.
+    *
+    * TODO: this could be OrderedMultiMap[Jlong, Row] indexed by row's 
timestamp, to avoid
+    * full map traversals (if we have lots of rows on the state that exceed 
`currentWatermark`).
+    */
+  private var leftState: MapState[JLong, Row] = _
+
+  /**
+    * Mapping from timestamp to right side `Row`.
+    *
+    * TODO: having `rightState` as an OrderedMapState would allow us to avoid 
sorting cost
+    * once per watermark
+    */
+  private var rightState: MapState[JLong, Row] = _
+
+  private var registeredTimer: ValueState[JLong] = _ // JLong for correct 
handling of default null
+
+  private var cRowWrapper: CRowWrappingCollector = _
+  private var collector: TimestampedCollector[CRow] = _
+  private var timerService: SimpleTimerService = _
+
+  private var joinFunction: FlatJoinFunction[Row, Row, Row] = _
+
+  override def open(): Unit = {
+    val clazz = compile(
+      getRuntimeContext.getUserCodeClassLoader,
+      genJoinFuncName,
+      genJoinFuncCode)
+
+    joinFunction = clazz.newInstance()
+
+    nextLeftIndex = getRuntimeContext.getState(
+      new ValueStateDescriptor[JLong](NEXT_LEFT_INDEX_STATE_NAME, 
BasicTypeInfo.LONG_TYPE_INFO))
+    leftState = getRuntimeContext.getMapState(
+      new MapStateDescriptor[JLong, Row](LEFT_STATE_NAME, 
BasicTypeInfo.LONG_TYPE_INFO, leftType))
+    rightState = getRuntimeContext.getMapState(
+      new MapStateDescriptor[JLong, Row](RIGHT_STATE_NAME, 
BasicTypeInfo.LONG_TYPE_INFO, rightType))
+    registeredTimer = getRuntimeContext.getState(
+      new ValueStateDescriptor[JLong](REGISTERED_TIMER_STATE_NAME, 
BasicTypeInfo.LONG_TYPE_INFO))
+
+    collector = new TimestampedCollector[CRow](output)
+    cRowWrapper = new CRowWrappingCollector()
+    cRowWrapper.out = collector
+    cRowWrapper.setChange(true)
+
+    val internalTimerService = getInternalTimerService(
+      TIMERS_STATE_NAME,
+      VoidNamespaceSerializer.INSTANCE,
+      this)
+
+    timerService = new SimpleTimerService(internalTimerService)
+  }
+
+  override def processElement1(element: StreamRecord[CRow]): Unit = {
+    if (!element.getValue.change) {
+      throw new TableException(
+        s"${classOf[TemporalRowtimeJoin].getSimpleName} does not support 
retractions on the " +
+          s"left side.")
+    }
+
+    leftState.put(getNextLeftIndex, element.getValue.row)
+    registerSmallestTimer(getLeftTime(element.getValue.row)) // Timer to emit 
and clean up the state
+  }
+
+  override def processElement2(element: StreamRecord[CRow]): Unit = {
+    if (!element.getValue.change) {
+      throw new TableException(
 
 Review comment:
   RowTime UpsertSource may make it possible. It would be good to validate 
during `translateToPlan` before running on a cluster.

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> Support versioned joins with event time
> ---------------------------------------
>
>                 Key: FLINK-9715
>                 URL: https://issues.apache.org/jira/browse/FLINK-9715
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>    Affects Versions: 1.5.0
>            Reporter: Piotr Nowojski
>            Assignee: Piotr Nowojski
>            Priority: Major
>              Labels: pull-request-available
>
> Queries like:
> {code:java}
> SELECT 
>   o.amount * r.rate 
> FROM 
>   Orders AS o, 
>   LATERAL TABLE (Rates(o.rowtime)) AS r 
> WHERE o.currency = r.currency{code}
> should work with event time



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