Examples with ShipStrategyType org.apache.flink.runtime.operators.shipping.ShipStrategyType used on opensource projects

Example 21 with ShipStrategyType

use of org.apache.flink.runtime.operators.shipping.ShipStrategyType in project flink by apache.

the class ReplicatingDataSourceTest method checkJoinWithReplicatedSourceInputBehindFlatMap.

/**
 * Tests join program with replicated data source behind flatMap.
 */
@Test
public void checkJoinWithReplicatedSourceInputBehindFlatMap() {
    ExecutionEnvironment env = ExecutionEnvironment.createLocalEnvironment();
    env.setParallelism(DEFAULT_PARALLELISM);
    TupleTypeInfo<Tuple1<String>> typeInfo = TupleTypeInfo.getBasicTupleTypeInfo(String.class);
    ReplicatingInputFormat<Tuple1<String>, FileInputSplit> rif = new ReplicatingInputFormat<Tuple1<String>, FileInputSplit>(new TupleCsvInputFormat<Tuple1<String>>(new Path("/some/path"), typeInfo));
    DataSet<Tuple1<String>> source1 = env.createInput(rif, new TupleTypeInfo<Tuple1<String>>(BasicTypeInfo.STRING_TYPE_INFO));
    DataSet<Tuple1<String>> source2 = env.readCsvFile("/some/otherpath").types(String.class);
    DataSink<Tuple2<Tuple1<String>, Tuple1<String>>> out = source1.flatMap(new IdFlatMap()).join(source2).where("*").equalTo("*").writeAsText("/some/newpath");
    Plan plan = env.createProgramPlan();
    // submit the plan to the compiler
    OptimizedPlan oPlan = compileNoStats(plan);
    // check the optimized Plan
    // when join should have forward strategy on both sides
    SinkPlanNode sinkNode = oPlan.getDataSinks().iterator().next();
    DualInputPlanNode joinNode = (DualInputPlanNode) sinkNode.getPredecessor();
    ShipStrategyType joinIn1 = joinNode.getInput1().getShipStrategy();
    ShipStrategyType joinIn2 = joinNode.getInput2().getShipStrategy();
    Assert.assertEquals("Invalid ship strategy for an operator.", ShipStrategyType.FORWARD, joinIn1);
    Assert.assertEquals("Invalid ship strategy for an operator.", ShipStrategyType.FORWARD, joinIn2);
}

Example 22 with ShipStrategyType

use of org.apache.flink.runtime.operators.shipping.ShipStrategyType in project flink by apache.

the class PlanJSONDumpGenerator method visit.

private boolean visit(DumpableNode<?> node, PrintWriter writer, boolean first) {
    // check for duplicate traversal
    if (this.nodeIds.containsKey(node)) {
        return false;
    }
    // assign an id first
    this.nodeIds.put(node, this.nodeCnt++);
    // then recurse
    for (DumpableNode<?> child : node.getPredecessors()) {
        // to set first to false!
        if (visit(child, writer, first)) {
            first = false;
        }
    }
    // check if this node should be skipped from the dump
    final OptimizerNode n = node.getOptimizerNode();
    // start a new node and output node id
    if (!first) {
        writer.print(",\n");
    }
    // open the node
    writer.print("\t{\n");
    // recurse, it is is an iteration node
    if (node instanceof BulkIterationNode || node instanceof BulkIterationPlanNode) {
        DumpableNode<?> innerChild = node instanceof BulkIterationNode ? ((BulkIterationNode) node).getNextPartialSolution() : ((BulkIterationPlanNode) node).getRootOfStepFunction();
        DumpableNode<?> begin = node instanceof BulkIterationNode ? ((BulkIterationNode) node).getPartialSolution() : ((BulkIterationPlanNode) node).getPartialSolutionPlanNode();
        writer.print("\t\t\"step_function\": [\n");
        visit(innerChild, writer, true);
        writer.print("\n\t\t],\n");
        writer.print("\t\t\"partial_solution\": " + this.nodeIds.get(begin) + ",\n");
        writer.print("\t\t\"next_partial_solution\": " + this.nodeIds.get(innerChild) + ",\n");
    } else if (node instanceof WorksetIterationNode || node instanceof WorksetIterationPlanNode) {
        DumpableNode<?> worksetRoot = node instanceof WorksetIterationNode ? ((WorksetIterationNode) node).getNextWorkset() : ((WorksetIterationPlanNode) node).getNextWorkSetPlanNode();
        DumpableNode<?> solutionDelta = node instanceof WorksetIterationNode ? ((WorksetIterationNode) node).getSolutionSetDelta() : ((WorksetIterationPlanNode) node).getSolutionSetDeltaPlanNode();
        DumpableNode<?> workset = node instanceof WorksetIterationNode ? ((WorksetIterationNode) node).getWorksetNode() : ((WorksetIterationPlanNode) node).getWorksetPlanNode();
        DumpableNode<?> solutionSet = node instanceof WorksetIterationNode ? ((WorksetIterationNode) node).getSolutionSetNode() : ((WorksetIterationPlanNode) node).getSolutionSetPlanNode();
        writer.print("\t\t\"step_function\": [\n");
        visit(worksetRoot, writer, true);
        visit(solutionDelta, writer, false);
        writer.print("\n\t\t],\n");
        writer.print("\t\t\"workset\": " + this.nodeIds.get(workset) + ",\n");
        writer.print("\t\t\"solution_set\": " + this.nodeIds.get(solutionSet) + ",\n");
        writer.print("\t\t\"next_workset\": " + this.nodeIds.get(worksetRoot) + ",\n");
        writer.print("\t\t\"solution_delta\": " + this.nodeIds.get(solutionDelta) + ",\n");
    }
    // print the id
    writer.print("\t\t\"id\": " + this.nodeIds.get(node));
    final String type;
    String contents;
    if (n instanceof DataSinkNode) {
        type = "sink";
        contents = n.getOperator().toString();
    } else if (n instanceof DataSourceNode) {
        type = "source";
        contents = n.getOperator().toString();
    } else if (n instanceof BulkIterationNode) {
        type = "bulk_iteration";
        contents = n.getOperator().getName();
    } else if (n instanceof WorksetIterationNode) {
        type = "workset_iteration";
        contents = n.getOperator().getName();
    } else if (n instanceof BinaryUnionNode) {
        type = "pact";
        contents = "";
    } else {
        type = "pact";
        contents = n.getOperator().getName();
    }
    contents = StringUtils.showControlCharacters(contents);
    if (encodeForHTML) {
        contents = StringEscapeUtils.escapeHtml4(contents);
        contents = contents.replace("\\", "&#92;");
    }
    String name = n.getOperatorName();
    if (name.equals("Reduce") && (node instanceof SingleInputPlanNode) && ((SingleInputPlanNode) node).getDriverStrategy() == DriverStrategy.SORTED_GROUP_COMBINE) {
        name = "Combine";
    }
    // output the type identifier
    writer.print(",\n\t\t\"type\": \"" + type + "\"");
    // output node name
    writer.print(",\n\t\t\"pact\": \"" + name + "\"");
    // output node contents
    writer.print(",\n\t\t\"contents\": \"" + contents + "\"");
    // parallelism
    writer.print(",\n\t\t\"parallelism\": \"" + (n.getParallelism() >= 1 ? n.getParallelism() : "default") + "\"");
    // output node predecessors
    Iterator<? extends DumpableConnection<?>> inConns = node.getDumpableInputs().iterator();
    String child1name = "", child2name = "";
    if (inConns != null && inConns.hasNext()) {
        // start predecessor list
        writer.print(",\n\t\t\"predecessors\": [");
        int inputNum = 0;
        while (inConns.hasNext()) {
            final DumpableConnection<?> inConn = inConns.next();
            final DumpableNode<?> source = inConn.getSource();
            writer.print(inputNum == 0 ? "\n" : ",\n");
            if (inputNum == 0) {
                child1name += child1name.length() > 0 ? ", " : "";
                child1name += source.getOptimizerNode().getOperator().getName() + " (id: " + this.nodeIds.get(source) + ")";
            } else if (inputNum == 1) {
                child2name += child2name.length() > 0 ? ", " : "";
                child2name += source.getOptimizerNode().getOperator().getName() + " (id: " + this.nodeIds.get(source) + ")";
            }
            // output predecessor id
            writer.print("\t\t\t{\"id\": " + this.nodeIds.get(source));
            // output connection side
            if (inConns.hasNext() || inputNum > 0) {
                writer.print(", \"side\": \"" + (inputNum == 0 ? "first" : "second") + "\"");
            }
            // output shipping strategy and channel type
            final Channel channel = (inConn instanceof Channel) ? (Channel) inConn : null;
            final ShipStrategyType shipType = channel != null ? channel.getShipStrategy() : inConn.getShipStrategy();
            String shipStrategy = null;
            if (shipType != null) {
                switch(shipType) {
                    case NONE:
                        // nothing
                        break;
                    case FORWARD:
                        shipStrategy = "Forward";
                        break;
                    case BROADCAST:
                        shipStrategy = "Broadcast";
                        break;
                    case PARTITION_HASH:
                        shipStrategy = "Hash Partition";
                        break;
                    case PARTITION_RANGE:
                        shipStrategy = "Range Partition";
                        break;
                    case PARTITION_RANDOM:
                        shipStrategy = "Redistribute";
                        break;
                    case PARTITION_FORCED_REBALANCE:
                        shipStrategy = "Rebalance";
                        break;
                    case PARTITION_CUSTOM:
                        shipStrategy = "Custom Partition";
                        break;
                    default:
                        throw new CompilerException("Unknown ship strategy '" + inConn.getShipStrategy().name() + "' in JSON generator.");
                }
            }
            if (channel != null && channel.getShipStrategyKeys() != null && channel.getShipStrategyKeys().size() > 0) {
                shipStrategy += " on " + (channel.getShipStrategySortOrder() == null ? channel.getShipStrategyKeys().toString() : Utils.createOrdering(channel.getShipStrategyKeys(), channel.getShipStrategySortOrder()).toString());
            }
            if (shipStrategy != null) {
                writer.print(", \"ship_strategy\": \"" + shipStrategy + "\"");
            }
            if (channel != null) {
                String localStrategy = null;
                switch(channel.getLocalStrategy()) {
                    case NONE:
                        break;
                    case SORT:
                        localStrategy = "Sort";
                        break;
                    case COMBININGSORT:
                        localStrategy = "Sort (combining)";
                        break;
                    default:
                        throw new CompilerException("Unknown local strategy " + channel.getLocalStrategy().name());
                }
                if (channel != null && channel.getLocalStrategyKeys() != null && channel.getLocalStrategyKeys().size() > 0) {
                    localStrategy += " on " + (channel.getLocalStrategySortOrder() == null ? channel.getLocalStrategyKeys().toString() : Utils.createOrdering(channel.getLocalStrategyKeys(), channel.getLocalStrategySortOrder()).toString());
                }
                if (localStrategy != null) {
                    writer.print(", \"local_strategy\": \"" + localStrategy + "\"");
                }
                if (channel != null && channel.getTempMode() != TempMode.NONE) {
                    String tempMode = channel.getTempMode().toString();
                    writer.print(", \"temp_mode\": \"" + tempMode + "\"");
                }
                if (channel != null) {
                    String exchangeMode = channel.getDataExchangeMode().toString();
                    writer.print(", \"exchange_mode\": \"" + exchangeMode + "\"");
                }
            }
            writer.print('}');
            inputNum++;
        }
        // finish predecessors
        writer.print("\n\t\t]");
    }
    // ---------------------------------------------------------------------------------------
    // the part below here is relevant only to plan nodes with concrete strategies, etc
    // ---------------------------------------------------------------------------------------
    final PlanNode p = node.getPlanNode();
    if (p == null) {
        // finish node
        writer.print("\n\t}");
        return true;
    }
    // local strategy
    String locString = null;
    if (p.getDriverStrategy() != null) {
        switch(p.getDriverStrategy()) {
            case NONE:
            case BINARY_NO_OP:
                break;
            case UNARY_NO_OP:
                locString = "No-Op";
                break;
            case MAP:
                locString = "Map";
                break;
            case FLAT_MAP:
                locString = "FlatMap";
                break;
            case MAP_PARTITION:
                locString = "Map Partition";
                break;
            case ALL_REDUCE:
                locString = "Reduce All";
                break;
            case ALL_GROUP_REDUCE:
            case ALL_GROUP_REDUCE_COMBINE:
                locString = "Group Reduce All";
                break;
            case SORTED_REDUCE:
                locString = "Sorted Reduce";
                break;
            case SORTED_PARTIAL_REDUCE:
                locString = "Sorted Combine/Reduce";
                break;
            case SORTED_GROUP_REDUCE:
                locString = "Sorted Group Reduce";
                break;
            case SORTED_GROUP_COMBINE:
                locString = "Sorted Combine";
                break;
            case HYBRIDHASH_BUILD_FIRST:
                locString = "Hybrid Hash (build: " + child1name + ")";
                break;
            case HYBRIDHASH_BUILD_SECOND:
                locString = "Hybrid Hash (build: " + child2name + ")";
                break;
            case HYBRIDHASH_BUILD_FIRST_CACHED:
                locString = "Hybrid Hash (CACHED) (build: " + child1name + ")";
                break;
            case HYBRIDHASH_BUILD_SECOND_CACHED:
                locString = "Hybrid Hash (CACHED) (build: " + child2name + ")";
                break;
            case NESTEDLOOP_BLOCKED_OUTER_FIRST:
                locString = "Nested Loops (Blocked Outer: " + child1name + ")";
                break;
            case NESTEDLOOP_BLOCKED_OUTER_SECOND:
                locString = "Nested Loops (Blocked Outer: " + child2name + ")";
                break;
            case NESTEDLOOP_STREAMED_OUTER_FIRST:
                locString = "Nested Loops (Streamed Outer: " + child1name + ")";
                break;
            case NESTEDLOOP_STREAMED_OUTER_SECOND:
                locString = "Nested Loops (Streamed Outer: " + child2name + ")";
                break;
            case INNER_MERGE:
                locString = "Merge";
                break;
            case CO_GROUP:
                locString = "Co-Group";
                break;
            default:
                locString = p.getDriverStrategy().name();
                break;
        }
        if (locString != null) {
            writer.print(",\n\t\t\"driver_strategy\": \"");
            writer.print(locString);
            writer.print("\"");
        }
    }
    {
        // output node global properties
        final GlobalProperties gp = p.getGlobalProperties();
        writer.print(",\n\t\t\"global_properties\": [\n");
        addProperty(writer, "Partitioning", gp.getPartitioning().name(), true);
        if (gp.getPartitioningFields() != null) {
            addProperty(writer, "Partitioned on", gp.getPartitioningFields().toString(), false);
        }
        if (gp.getPartitioningOrdering() != null) {
            addProperty(writer, "Partitioning Order", gp.getPartitioningOrdering().toString(), false);
        } else {
            addProperty(writer, "Partitioning Order", "(none)", false);
        }
        if (n.getUniqueFields() == null || n.getUniqueFields().size() == 0) {
            addProperty(writer, "Uniqueness", "not unique", false);
        } else {
            addProperty(writer, "Uniqueness", n.getUniqueFields().toString(), false);
        }
        writer.print("\n\t\t]");
    }
    {
        // output node local properties
        LocalProperties lp = p.getLocalProperties();
        writer.print(",\n\t\t\"local_properties\": [\n");
        if (lp.getOrdering() != null) {
            addProperty(writer, "Order", lp.getOrdering().toString(), true);
        } else {
            addProperty(writer, "Order", "(none)", true);
        }
        if (lp.getGroupedFields() != null && lp.getGroupedFields().size() > 0) {
            addProperty(writer, "Grouped on", lp.getGroupedFields().toString(), false);
        } else {
            addProperty(writer, "Grouping", "not grouped", false);
        }
        if (n.getUniqueFields() == null || n.getUniqueFields().size() == 0) {
            addProperty(writer, "Uniqueness", "not unique", false);
        } else {
            addProperty(writer, "Uniqueness", n.getUniqueFields().toString(), false);
        }
        writer.print("\n\t\t]");
    }
    // output node size estimates
    writer.print(",\n\t\t\"estimates\": [\n");
    addProperty(writer, "Est. Output Size", n.getEstimatedOutputSize() == -1 ? "(unknown)" : formatNumber(n.getEstimatedOutputSize(), "B"), true);
    addProperty(writer, "Est. Cardinality", n.getEstimatedNumRecords() == -1 ? "(unknown)" : formatNumber(n.getEstimatedNumRecords()), false);
    writer.print("\t\t]");
    // output node cost
    if (p.getNodeCosts() != null) {
        writer.print(",\n\t\t\"costs\": [\n");
        addProperty(writer, "Network", p.getNodeCosts().getNetworkCost() == -1 ? "(unknown)" : formatNumber(p.getNodeCosts().getNetworkCost(), "B"), true);
        addProperty(writer, "Disk I/O", p.getNodeCosts().getDiskCost() == -1 ? "(unknown)" : formatNumber(p.getNodeCosts().getDiskCost(), "B"), false);
        addProperty(writer, "CPU", p.getNodeCosts().getCpuCost() == -1 ? "(unknown)" : formatNumber(p.getNodeCosts().getCpuCost(), ""), false);
        addProperty(writer, "Cumulative Network", p.getCumulativeCosts().getNetworkCost() == -1 ? "(unknown)" : formatNumber(p.getCumulativeCosts().getNetworkCost(), "B"), false);
        addProperty(writer, "Cumulative Disk I/O", p.getCumulativeCosts().getDiskCost() == -1 ? "(unknown)" : formatNumber(p.getCumulativeCosts().getDiskCost(), "B"), false);
        addProperty(writer, "Cumulative CPU", p.getCumulativeCosts().getCpuCost() == -1 ? "(unknown)" : formatNumber(p.getCumulativeCosts().getCpuCost(), ""), false);
        writer.print("\n\t\t]");
    }
    // output the node compiler hints
    if (n.getOperator().getCompilerHints() != null) {
        CompilerHints hints = n.getOperator().getCompilerHints();
        CompilerHints defaults = new CompilerHints();
        String size = hints.getOutputSize() == defaults.getOutputSize() ? "(none)" : String.valueOf(hints.getOutputSize());
        String card = hints.getOutputCardinality() == defaults.getOutputCardinality() ? "(none)" : String.valueOf(hints.getOutputCardinality());
        String width = hints.getAvgOutputRecordSize() == defaults.getAvgOutputRecordSize() ? "(none)" : String.valueOf(hints.getAvgOutputRecordSize());
        String filter = hints.getFilterFactor() == defaults.getFilterFactor() ? "(none)" : String.valueOf(hints.getFilterFactor());
        writer.print(",\n\t\t\"compiler_hints\": [\n");
        addProperty(writer, "Output Size (bytes)", size, true);
        addProperty(writer, "Output Cardinality", card, false);
        addProperty(writer, "Avg. Output Record Size (bytes)", width, false);
        addProperty(writer, "Filter Factor", filter, false);
        writer.print("\t\t]");
    }
    // finish node
    writer.print("\n\t}");
    return true;
}

Example 23 with ShipStrategyType

use of org.apache.flink.runtime.operators.shipping.ShipStrategyType in project flink by apache.

the class BinaryUnionNode method getAlternativePlans.

@Override
public List<PlanNode> getAlternativePlans(CostEstimator estimator) {
    // check that union has only a single successor
    if (this.getOutgoingConnections().size() > 1) {
        throw new CompilerException("BinaryUnionNode has more than one successor.");
    }
    boolean childrenSkippedDueToReplicatedInput = false;
    // check if we have a cached version
    if (this.cachedPlans != null) {
        return this.cachedPlans;
    }
    // step down to all producer nodes and calculate alternative plans
    final List<? extends PlanNode> subPlans1 = getFirstPredecessorNode().getAlternativePlans(estimator);
    final List<? extends PlanNode> subPlans2 = getSecondPredecessorNode().getAlternativePlans(estimator);
    List<DagConnection> broadcastConnections = getBroadcastConnections();
    if (broadcastConnections != null && broadcastConnections.size() > 0) {
        throw new CompilerException("Found BroadcastVariables on a Union operation");
    }
    final ArrayList<PlanNode> outputPlans = new ArrayList<PlanNode>();
    final List<Set<? extends NamedChannel>> broadcastPlanChannels = Collections.emptyList();
    final BinaryUnionOpDescriptor operator = new BinaryUnionOpDescriptor();
    final RequestedLocalProperties noLocalProps = new RequestedLocalProperties();
    final ExecutionMode input1Mode = this.input1.getDataExchangeMode();
    final ExecutionMode input2Mode = this.input2.getDataExchangeMode();
    final int parallelism = getParallelism();
    final int inParallelism1 = getFirstPredecessorNode().getParallelism();
    final int inParallelism2 = getSecondPredecessorNode().getParallelism();
    final boolean dopChange1 = parallelism != inParallelism1;
    final boolean dopChange2 = parallelism != inParallelism2;
    final boolean input1breakPipeline = this.input1.isBreakingPipeline();
    final boolean input2breakPipeline = this.input2.isBreakingPipeline();
    // create all candidates
    for (PlanNode child1 : subPlans1) {
        if (child1.getGlobalProperties().isFullyReplicated()) {
            // fully replicated input is always locally forwarded if parallelism is not changed
            if (dopChange1) {
                // can not continue with this child
                childrenSkippedDueToReplicatedInput = true;
                continue;
            } else {
                this.input1.setShipStrategy(ShipStrategyType.FORWARD);
            }
        }
        for (PlanNode child2 : subPlans2) {
            if (child2.getGlobalProperties().isFullyReplicated()) {
                // changed
                if (dopChange2) {
                    // can not continue with this child
                    childrenSkippedDueToReplicatedInput = true;
                    continue;
                } else {
                    this.input2.setShipStrategy(ShipStrategyType.FORWARD);
                }
            }
            // candidate at the joined branch plan.
            if (!areBranchCompatible(child1, child2)) {
                continue;
            }
            for (RequestedGlobalProperties igps : this.channelProps) {
                // create a candidate channel for the first input. mark it cached, if the
                // connection says so
                Channel c1 = new Channel(child1, this.input1.getMaterializationMode());
                if (this.input1.getShipStrategy() == null) {
                    // free to choose the ship strategy
                    igps.parameterizeChannel(c1, dopChange1, input1Mode, input1breakPipeline);
                    // ship strategy preserves/establishes them even under changing parallelisms
                    if (dopChange1 && !c1.getShipStrategy().isNetworkStrategy()) {
                        c1.getGlobalProperties().reset();
                    }
                } else {
                    // ship strategy fixed by compiler hint
                    ShipStrategyType shipStrategy = this.input1.getShipStrategy();
                    DataExchangeMode exMode = DataExchangeMode.select(input1Mode, shipStrategy, input1breakPipeline);
                    if (this.keys1 != null) {
                        c1.setShipStrategy(this.input1.getShipStrategy(), this.keys1.toFieldList(), exMode);
                    } else {
                        c1.setShipStrategy(this.input1.getShipStrategy(), exMode);
                    }
                    if (dopChange1) {
                        c1.adjustGlobalPropertiesForFullParallelismChange();
                    }
                }
                // create a candidate channel for the second input. mark it cached, if the
                // connection says so
                Channel c2 = new Channel(child2, this.input2.getMaterializationMode());
                if (this.input2.getShipStrategy() == null) {
                    // free to choose the ship strategy
                    igps.parameterizeChannel(c2, dopChange2, input2Mode, input2breakPipeline);
                    // ship strategy preserves/establishes them even under changing parallelisms
                    if (dopChange2 && !c2.getShipStrategy().isNetworkStrategy()) {
                        c2.getGlobalProperties().reset();
                    }
                } else {
                    // ship strategy fixed by compiler hint
                    ShipStrategyType shipStrategy = this.input2.getShipStrategy();
                    DataExchangeMode exMode = DataExchangeMode.select(input2Mode, shipStrategy, input2breakPipeline);
                    if (this.keys2 != null) {
                        c2.setShipStrategy(this.input2.getShipStrategy(), this.keys2.toFieldList(), exMode);
                    } else {
                        c2.setShipStrategy(this.input2.getShipStrategy(), exMode);
                    }
                    if (dopChange2) {
                        c2.adjustGlobalPropertiesForFullParallelismChange();
                    }
                }
                // get the global properties and clear unique fields (not preserved anyways
                // during the union)
                GlobalProperties p1 = c1.getGlobalProperties();
                GlobalProperties p2 = c2.getGlobalProperties();
                p1.clearUniqueFieldCombinations();
                p2.clearUniqueFieldCombinations();
                // partitioned on that field.
                if (!igps.isTrivial() && !(p1.equals(p2))) {
                    if (c1.getShipStrategy() == ShipStrategyType.FORWARD && c2.getShipStrategy() != ShipStrategyType.FORWARD) {
                        // adjust c2 to c1
                        c2 = c2.clone();
                        p1.parameterizeChannel(c2, dopChange2, input2Mode, input2breakPipeline);
                    } else if (c2.getShipStrategy() == ShipStrategyType.FORWARD && c1.getShipStrategy() != ShipStrategyType.FORWARD) {
                        // adjust c1 to c2
                        c1 = c1.clone();
                        p2.parameterizeChannel(c1, dopChange1, input1Mode, input1breakPipeline);
                    } else if (c1.getShipStrategy() == ShipStrategyType.FORWARD && c2.getShipStrategy() == ShipStrategyType.FORWARD) {
                        boolean adjustC1 = c1.getEstimatedOutputSize() <= 0 || c2.getEstimatedOutputSize() <= 0 || c1.getEstimatedOutputSize() <= c2.getEstimatedOutputSize();
                        if (adjustC1) {
                            c2 = c2.clone();
                            p1.parameterizeChannel(c2, dopChange2, input2Mode, input2breakPipeline);
                        } else {
                            c1 = c1.clone();
                            p2.parameterizeChannel(c1, dopChange1, input1Mode, input1breakPipeline);
                        }
                    } else {
                        // excluded by the check that the required strategies must match
                        throw new CompilerException("Bug in Plan Enumeration for Union Node.");
                    }
                }
                instantiate(operator, c1, c2, broadcastPlanChannels, outputPlans, estimator, igps, igps, noLocalProps, noLocalProps);
            }
        }
    }
    if (outputPlans.isEmpty()) {
        if (childrenSkippedDueToReplicatedInput) {
            throw new CompilerException("No plan meeting the requirements could be created @ " + this + ". Most likely reason: Invalid use of replicated input.");
        } else {
            throw new CompilerException("No plan meeting the requirements could be created @ " + this + ". Most likely reason: Too restrictive plan hints.");
        }
    }
    // cost and prune the plans
    for (PlanNode node : outputPlans) {
        estimator.costOperator(node);
    }
    prunePlanAlternatives(outputPlans);
    outputPlans.trimToSize();
    this.cachedPlans = outputPlans;
    return outputPlans;
}