@Override
public List<PlanNode> getAlternativePlans(CostEstimator estimator) {
// check if we have a cached version
if (this.cachedPlans != null) {
return this.cachedPlans;
}
boolean childrenSkippedDueToReplicatedInput = false;
// calculate alternative sub-plans for predecessor
final List<? extends PlanNode> subPlans = getPredecessorNode().getAlternativePlans(estimator);
final Set<RequestedGlobalProperties> intGlobal =
this.inConn.getInterestingProperties().getGlobalProperties();
// calculate alternative sub-plans for broadcast inputs
final List<Set<? extends NamedChannel>> broadcastPlanChannels =
new ArrayList<Set<? extends NamedChannel>>();
List<DagConnection> broadcastConnections = getBroadcastConnections();
List<String> broadcastConnectionNames = getBroadcastConnectionNames();
for (int i = 0; i < broadcastConnections.size(); i++) {
DagConnection broadcastConnection = broadcastConnections.get(i);
String broadcastConnectionName = broadcastConnectionNames.get(i);
List<PlanNode> broadcastPlanCandidates =
broadcastConnection.getSource().getAlternativePlans(estimator);
// wrap the plan candidates in named channels
HashSet<NamedChannel> broadcastChannels =
new HashSet<NamedChannel>(broadcastPlanCandidates.size());
for (PlanNode plan : broadcastPlanCandidates) {
NamedChannel c = new NamedChannel(broadcastConnectionName, plan);
DataExchangeMode exMode =
DataExchangeMode.select(
broadcastConnection.getDataExchangeMode(),
ShipStrategyType.BROADCAST,
broadcastConnection.isBreakingPipeline());
c.setShipStrategy(ShipStrategyType.BROADCAST, exMode);
broadcastChannels.add(c);
}
broadcastPlanChannels.add(broadcastChannels);
}
final RequestedGlobalProperties[] allValidGlobals;
{
Set<RequestedGlobalProperties> pairs = new HashSet<RequestedGlobalProperties>();
for (OperatorDescriptorSingle ods : getPossibleProperties()) {
pairs.addAll(ods.getPossibleGlobalProperties());
}
allValidGlobals = pairs.toArray(new RequestedGlobalProperties[pairs.size()]);
}
final ArrayList<PlanNode> outputPlans = new ArrayList<PlanNode>();
final ExecutionMode executionMode = this.inConn.getDataExchangeMode();
final int parallelism = getParallelism();
final int inParallelism = getPredecessorNode().getParallelism();
final boolean parallelismChange = inParallelism != parallelism;
final boolean breaksPipeline = this.inConn.isBreakingPipeline();
// create all candidates
for (PlanNode child : subPlans) {
if (child.getGlobalProperties().isFullyReplicated()) {
// fully replicated input is always locally forwarded if the parallelism is not changed
if (parallelismChange) {
// can not continue with this child
childrenSkippedDueToReplicatedInput = true;
continue;
} else {
this.inConn.setShipStrategy(ShipStrategyType.FORWARD);
}
}
if (this.inConn.getShipStrategy() == null) {
// pick the strategy ourselves
for (RequestedGlobalProperties igps : intGlobal) {
final Channel c = new Channel(child, this.inConn.getMaterializationMode());
igps.parameterizeChannel(c, parallelismChange, executionMode, breaksPipeline);
// if the parallelism changed, make sure that we cancel out properties, unless the
// ship strategy preserves/establishes them even under changing parallelisms
if (parallelismChange && !c.getShipStrategy().isNetworkStrategy()) {
c.getGlobalProperties().reset();
}
// check whether we meet any of the accepted properties
// we may remove this check, when we do a check to not inherit
// requested global properties that are incompatible with all possible
// requested properties
for (RequestedGlobalProperties rgps : allValidGlobals) {
if (rgps.isMetBy(c.getGlobalProperties())) {
c.setRequiredGlobalProps(rgps);
addLocalCandidates(c, broadcastPlanChannels, igps, outputPlans, estimator);
break;
}
}
}
} else {
// hint fixed the strategy
final Channel c = new Channel(child, this.inConn.getMaterializationMode());
final ShipStrategyType shipStrategy = this.inConn.getShipStrategy();
final DataExchangeMode exMode =
DataExchangeMode.select(executionMode, shipStrategy, breaksPipeline);
if (this.keys != null) {
c.setShipStrategy(shipStrategy, this.keys.toFieldList(), exMode);
} else {
c.setShipStrategy(shipStrategy, exMode);
}
if (parallelismChange) {
c.adjustGlobalPropertiesForFullParallelismChange();
}
// check whether we meet any of the accepted properties
for (RequestedGlobalProperties rgps : allValidGlobals) {
if (rgps.isMetBy(c.getGlobalProperties())) {
addLocalCandidates(c, broadcastPlanChannels, rgps, outputPlans, estimator);
break;
}
}
}
}
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;
}
