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ASF GitHub Bot commented on FLINK-3179: --------------------------------------- Github user fhueske commented on a diff in the pull request: https://github.com/apache/flink/pull/1553#discussion_r55205324 --- Diff: flink-optimizer/src/main/java/org/apache/flink/optimizer/operators/GroupReduceWithCombineProperties.java --- @@ -126,12 +117,66 @@ public SingleInputPlanNode instantiate(Channel in, SingleInputNode node) { } toReducer.setLocalStrategy(LocalStrategy.COMBININGSORT, in.getLocalStrategyKeys(), in.getLocalStrategySortOrder()); - return new SingleInputPlanNode(node, "Reduce ("+node.getOperator().getName()+")", toReducer, DriverStrategy.SORTED_GROUP_REDUCE, this.keyList); } } + private SingleInputPlanNode injectCombinerBeforPartitioner(Channel in, SingleInputNode node) { + // Inject a combiner before the partition node + Channel channelWithPartitionSrc = new Channel(in.getSource()); + GroupReduceNode combinerNode = ((GroupReduceNode) node).getCombinerUtilityNode(); + combinerNode.setParallelism(in.getSource().getParallelism()); + if(in.getSource().getInputs().iterator().hasNext()) { + Channel oldChannelToPartitioner = channelWithPartitionSrc.getSource().getInputs().iterator().next(); + Channel toCombiner = new Channel(oldChannelToPartitioner.getSource()); + // A combiner plan node is created with the channel as input that has the partitioner as the target + toCombiner.setShipStrategy(ShipStrategyType.FORWARD, DataExchangeMode.PIPELINED); + SingleInputPlanNode combiner = new SingleInputPlanNode(combinerNode, "Combine("+node.getOperator() + .getName()+")", toCombiner, DriverStrategy.SORTED_GROUP_COMBINE); + setCombinerProperties(in, oldChannelToPartitioner, combiner); + + Channel toPartitioner = new Channel(combiner); + // Set the actual partitioner node's strategy key and strategy order + toPartitioner.setShipStrategy(oldChannelToPartitioner.getShipStrategy(), oldChannelToPartitioner.getShipStrategyKeys(), + oldChannelToPartitioner.getShipStrategySortOrder(), oldChannelToPartitioner.getDataExchangeMode()); + // Create the partition single input plan node from the existing partition node + PlanNode partitionplanNode = in.getSource().getPlanNode(); + SingleInputPlanNode partition = new SingleInputPlanNode(in.getSource().getOptimizerNode(), partitionplanNode.getNodeName(), + toPartitioner, partitionplanNode.getDriverStrategy()); + partition.setCosts(partitionplanNode.getNodeCosts()); + partition.initProperties(partitionplanNode.getGlobalProperties(), partitionplanNode.getLocalProperties()); + // Create a reducer such that the input of the reducer is the partition node + Channel toReducer = new Channel(partition); + toReducer.setShipStrategy(in.getShipStrategy(), in.getShipStrategyKeys(), + in.getShipStrategySortOrder(), in.getDataExchangeMode()); + return getReducerSingleInputPlanNode(toReducer, node); + } else { + return getReducerSingleInputPlanNode(in, node); --- End diff -- in.getSource is the partitioner an should thus have exactly one input. If this is not the case, something is wrong and we should throw a `CompilerException`. > Combiner is not injected if Reduce or GroupReduce input is explicitly > partitioned > --------------------------------------------------------------------------------- > > Key: FLINK-3179 > URL: https://issues.apache.org/jira/browse/FLINK-3179 > Project: Flink > Issue Type: Bug > Components: Optimizer > Affects Versions: 0.10.1 > Reporter: Fabian Hueske > Assignee: ramkrishna.s.vasudevan > Priority: Critical > Fix For: 1.0.0, 0.10.2 > > > The optimizer does not inject a combiner if the input of a Reducer or > GroupReducer is explicitly partitioned as in the following example > {code} > DataSet<Tuple2<String,Integer>> words = ... > DataSet<Tuple2<String,Integer>> counts = words > .partitionByHash(0) > .groupBy(0) > .sum(1); > {code} > Explicit partitioning can be useful to enforce partitioning on a subset of > keys or to use a different partitioning method (custom or range partitioning). > This issue should be fixed by changing the {{instantiate()}} methods of the > {{ReduceProperties}} and {{GroupReduceWithCombineProperties}} classes such > that a combine is injected in front of a {{PartitionPlanNode}} if it is the > input of a Reduce or GroupReduce operator. This should only happen, if the > Reducer is the only successor of the Partition operator. -- This message was sent by Atlassian JIRA (v6.3.4#6332)