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https://issues.apache.org/jira/browse/FLINK-3850?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15902050#comment-15902050
]
ASF GitHub Bot commented on FLINK-3850:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3040#discussion_r104706099
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/dataset/forwarding/FieldForwardingUtils.scala
---
@@ -0,0 +1,143 @@
+/*
+ * 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.dataset.forwarding
+
+import org.apache.flink.api.common.typeinfo.{BasicArrayTypeInfo,
BasicTypeInfo, TypeInformation => TypeInfo}
+import org.apache.flink.api.common.typeutils.CompositeType
+import org.apache.flink.api.java.DataSet
+import org.apache.flink.table.api.TableException
+import org.apache.flink.types.Row
+
+object FieldForwardingUtils {
+
+ def compositeTypeField = (fields: Seq[(String, TypeInfo[_])]) => fields
+
+ private def throwMissedWrapperException(customWrapper: TypeInfo[_]) = {
+ throw new TableException(s"Implementation for $customWrapper wrapper
is missing.")
+ }
+
+ /**
+ * Wrapper for {@link getForwardedFields}
+ */
+ def getForwardedInput(
+ inputType: TypeInfo[_],
+ outputType: TypeInfo[_],
+ forwardIndices: Seq[Int],
+ customWrapper: TypeInfo[_] =>
+ Seq[(String, TypeInfo[_])] = throwMissedWrapperException): String
= {
+
+ getForwardedFields(inputType,
+ outputType,
+ forwardIndices.zip(forwardIndices),
+ customWrapper)
+ }
+
+ /**
+ * Wraps provided indices with proper names.
+ * e.g. _1 for Tuple, f0 for Row, fieldName for POJO and named Row
+ *
+ * @param inputType information of input data
+ * @param outputType information of output data
+ * @param forwardIndices tuple of (input, output) indices of a
forwarded field
+ * @param customWrapper used for figuring out proper type in specific
cases,
+ * e.g. {@see DataSetSingleRowJoin}
+ * @return string with forwarded fields mapped from input to output
+ */
+ def getForwardedFields(
+ inputType: TypeInfo[_],
+ outputType: TypeInfo[_],
+ forwardIndices: Seq[(Int, Int)],
+ customWrapper: TypeInfo[_] =>
+ Seq[(String, TypeInfo[_])] = throwMissedWrapperException): String
= {
+
+ def chooseWrapper(
+ typeInformation: TypeInfo[_]): Seq[(String, TypeInfo[_])] = {
+
+ typeInformation match {
+ case composite: CompositeType[_] =>
+ val fields = extractFields(composite)
+ compositeTypeField(fields)
+ case basic: BasicTypeInfo[_] =>
+ Seq((s"*", basic))
+ case array: BasicArrayTypeInfo[_, _] =>
+ Seq((s"*", array))
+ case _ =>
+ customWrapper(typeInformation)
+ }
+ }
+
+ val wrapInput = chooseWrapper(inputType)
+ val wrapOutput = chooseWrapper(outputType)
+
+ forwardFields(forwardIndices, wrapInput, wrapOutput)
+ }
+
+ private def extractFields(
+ composite: CompositeType[_]): Seq[(String, TypeInfo[_])] = {
+
+ val types = for {
+ i <- 0 until composite.getArity
+ } yield { composite.getTypeAt(i) }
+
+ composite.getFieldNames.zip(types)
+ }
+
+ private def forwardFields(
+ forwardIndices: Seq[(Int, Int)],
+ wrappedInput: Int => (String, TypeInfo[_]),
+ wrappedOutput: Int => (String, TypeInfo[_])): String = {
+
+ implicit class Field2ForwardField(left: (String, TypeInfo[_])) {
+ def ->(right: (String, TypeInfo[_])): String = if
(left.equals(right)) {
+ s"${left._1}"
+ } else {
+ if (left._2.equals(right._2)) {
+ s"${left._1}->${right._1}"
+ } else {
+ null
--- End diff --
We should throw an exception here. If the types do not match, the logic to
identify the mapping of forwarded fields is broken. If the wrongly mapped
fields had the same type we would not recognize that.
> Add forward field annotations to DataSet operators generated by the Table API
> -----------------------------------------------------------------------------
>
> Key: FLINK-3850
> URL: https://issues.apache.org/jira/browse/FLINK-3850
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Nikolay Vasilishin
>
> The DataSet API features semantic annotations [1] to hint the optimizer which
> input fields an operator copies. This information is valuable for the
> optimizer because it can infer that certain physical properties such as
> partitioning or sorting are not destroyed by user functions and thus generate
> more efficient execution plans.
> The Table API is built on top of the DataSet API and generates DataSet
> programs and code for user-defined functions. Hence, it knows exactly which
> fields are modified and which not. We should use this information to
> automatically generate forward field annotations and attach them to the
> operators. This can help to significantly improve the performance of certain
> jobs.
> [1]
> https://ci.apache.org/projects/flink/flink-docs-release-1.0/apis/batch/index.html#semantic-annotations
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