Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/4266#discussion_r127178517
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/datastream/DataStreamWindowJoin.scala
---
@@ -0,0 +1,187 @@
+/*
+ * 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.plan.nodes.datastream
+
+import org.apache.calcite.plan._
+import org.apache.calcite.rel.core.{JoinInfo, JoinRelType}
+import org.apache.calcite.rel.{BiRel, RelNode, RelWriter}
+import org.apache.calcite.rex.RexNode
+import org.apache.flink.api.java.functions.NullByteKeySelector
+import org.apache.flink.streaming.api.datastream.DataStream
+import org.apache.flink.table.api.{StreamQueryConfig,
StreamTableEnvironment, TableException}
+import org.apache.flink.table.plan.nodes.CommonJoin
+import org.apache.flink.table.plan.schema.RowSchema
+import org.apache.flink.table.runtime.join.{ProcTimeWindowInnerJoin,
WindowJoinUtil}
+import org.apache.flink.table.runtime.types.{CRow, CRowTypeInfo}
+import org.apache.flink.table.updateutils.UpdateCheckUtils
+
+/**
+ * Flink RelNode which matches along with JoinOperator and its related
operations.
+ */
+class DataStreamWindowJoin(
+ cluster: RelOptCluster,
+ traitSet: RelTraitSet,
+ leftNode: RelNode,
+ rightNode: RelNode,
+ joinCondition: RexNode,
+ joinType: JoinRelType,
+ leftSchema: RowSchema,
+ rightSchema: RowSchema,
+ schema: RowSchema,
+ isRowTime: Boolean,
+ leftLowerBound: Long,
+ leftUpperBound: Long,
+ remainCondition: Option[RexNode],
+ ruleDescription: String)
+ extends BiRel(cluster, traitSet, leftNode, rightNode)
+ with CommonJoin
+ with DataStreamRel {
+
+ override def deriveRowType() = schema.logicalType
+
+ override def copy(traitSet: RelTraitSet, inputs:
java.util.List[RelNode]): RelNode = {
+ new DataStreamWindowJoin(
+ cluster,
+ traitSet,
+ inputs.get(0),
+ inputs.get(1),
+ joinCondition,
+ joinType,
+ leftSchema,
+ rightSchema,
+ schema,
+ isRowTime,
+ leftLowerBound,
+ leftUpperBound,
+ remainCondition,
+ ruleDescription)
+ }
+
+ override def toString: String = {
+ joinToString(
+ schema.logicalType,
+ joinCondition,
+ joinType,
+ getExpressionString)
+ }
+
+ override def explainTerms(pw: RelWriter): RelWriter = {
+ joinExplainTerms(
+ super.explainTerms(pw),
+ schema.logicalType,
+ joinCondition,
+ joinType,
+ getExpressionString)
+ }
+
+ override def translateToPlan(
+ tableEnv: StreamTableEnvironment,
+ queryConfig: StreamQueryConfig): DataStream[CRow] = {
+
+ val config = tableEnv.getConfig
+
+ val isLeftAppendOnly = UpdateCheckUtils.isAppendOnly(left)
--- End diff --
the ` UpdateCheckUtils.isAppendOnly` recursively checks if any downstream
operator produces updates. As soon as any downstream operator produces updates,
the given operator has to be able to handle them.
Updates can be encodes as retraction or be implicit per key-wise updates if
the update producing and receiving operators use the same keys. Retraction
updates are encoded as two messages. Non-retraction updates are encoded as
single message and require a key to which they relate (`CRow.change == true` ->
insert or update per key, `CRow.change == false` -> delete on key). Right now,
only UpsertTableSinks use non-retraction updates, but other operators such as
unbounded joins will use it as well.
So even if `AccRetract` is false, the input might produce updates but those
updates are differently encoded, i.e., in a single message. The window stream
join is not able to handle updates (it ignores the `CRow.change` flag).
Therefore, we must ensure that the inputs do not produce updates.
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