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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_r104727584 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/dataset/DataSetJoin.scala --- @@ -199,10 +200,21 @@ class DataSetJoin( val joinOpName = s"where: ($joinConditionToString), join: ($joinSelectionToString)" + //consider all fields not which are not keys are forwarded + val leftIndices = (0 until left.getRowType.getFieldCount).diff(leftKeys) --- End diff -- The keys can also be forwarded. Actually, these are the most interesting fields because the DataSet will be partitioned and maybe also sorted on these keys. > 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 -- This message was sent by Atlassian JIRA (v6.3.15#6346)