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https://issues.apache.org/jira/browse/FLINK-5159?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15704624#comment-15704624
]
ASF GitHub Bot commented on FLINK-5159:
---------------------------------------
Github user AlexanderShoshin commented on a diff in the pull request:
https://github.com/apache/flink/pull/2811#discussion_r89957777
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/api/table/plan/nodes/dataset/DataSetSingleRowJoin.scala
---
@@ -0,0 +1,229 @@
+/*
+ * 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.api.table.plan.nodes.dataset
+
+import org.apache.calcite.plan._
+import org.apache.calcite.rel.`type`.{RelDataType, RelDataTypeField}
+import org.apache.calcite.rel.metadata.RelMetadataQuery
+import org.apache.calcite.rel.{BiRel, RelNode, RelWriter}
+import org.apache.calcite.rex.RexNode
+import org.apache.calcite.util.mapping.IntPair
+import org.apache.flink.api.common.functions.{FlatJoinFunction,
FlatMapFunction}
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.java.DataSet
+import org.apache.flink.api.table.codegen.CodeGenerator
+import org.apache.flink.api.table.runtime.{MapJoinLeftRunner,
MapJoinRightRunner}
+import
org.apache.flink.api.table.typeutils.TypeConverter.determineReturnType
+import org.apache.flink.api.table.{BatchTableEnvironment, TableConfig,
TableException}
+
+import scala.collection.JavaConversions._
+import scala.collection.JavaConverters._
+
+/**
+ * Flink RelNode that executes a Join where one of inputs is a single row.
+ */
+class DataSetSingleRowJoin(
+ cluster: RelOptCluster,
+ traitSet: RelTraitSet,
+ leftNode: RelNode,
+ rightNode: RelNode,
+ leftIsSingle: Boolean,
+ rowRelDataType: RelDataType,
+ joinCondition: RexNode,
+ joinRowType: RelDataType,
+ keyPairs: List[IntPair],
+ ruleDescription: String)
+ extends BiRel(cluster, traitSet, leftNode, rightNode)
+ with DataSetRel {
+
+ override def deriveRowType() = rowRelDataType
+
+ override def copy(traitSet: RelTraitSet, inputs:
java.util.List[RelNode]): RelNode = {
+ new DataSetSingleRowJoin(
+ cluster,
+ traitSet,
+ inputs.get(0),
+ inputs.get(1),
+ leftIsSingle,
+ getRowType,
+ joinCondition,
+ joinRowType,
+ keyPairs,
+ ruleDescription)
+ }
+
+ override def toString: String = {
+ s"$joinTypeToString(where: ($joinConditionToString), join:
($joinSelectionToString))"
+ }
+
+ override def explainTerms(pw: RelWriter): RelWriter = {
+ super.explainTerms(pw)
+ .item("where", joinConditionToString)
+ .item("join", joinSelectionToString)
+ .item("joinType", joinTypeToString)
+ }
+
+ override def computeSelfCost (planner: RelOptPlanner, metadata:
RelMetadataQuery): RelOptCost = {
+ val children = this.getInputs
+ children.foldLeft(planner.getCostFactory.makeZeroCost()) { (cost,
child) =>
+ if (leftIsSingle && child.equals(right) ||
+ !leftIsSingle && child.equals(left)) {
+ val rowCnt = metadata.getRowCount(child)
+ val rowSize = this.estimateRowSize(child.getRowType)
+ cost.plus(planner.getCostFactory.makeCost(rowCnt, rowCnt, rowCnt *
rowSize))
+ } else {
+ cost
+ }
+ }
+ }
+
+ override def translateToPlan(
+ tableEnv: BatchTableEnvironment,
+ expectedType: Option[TypeInformation[Any]]): DataSet[Any] = {
+
+ if (isConditionTypesCompatible(left.getRowType.getFieldList,
--- End diff --
This will catch a case when we compare different types in `WHERE`
expression:
```
SELECT *
FROM A, (SELECT min(b1) AS b1 FROM B)
WHERE a3 = b1
```
Should this `SELECT` throw an exception if a3 is a `String` and b1 is an
`Int`?
> Improve perfomance of inner joins with a single row input
> ---------------------------------------------------------
>
> Key: FLINK-5159
> URL: https://issues.apache.org/jira/browse/FLINK-5159
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: Alexander Shoshin
> Assignee: Alexander Shoshin
> Priority: Minor
>
> All inner joins (including a cross join) can be implemented as a
> {{MapFunction}} if one of their inputs is a single row. This row can be
> passed to a {{MapFunction}} as a {{BroadcastSet}}.
> This approach is going to be more lightweight than the other current
> strategies.
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