@Override
protected void instantiateCandidate(
OperatorDescriptorSingle dps,
Channel in,
List<Set<? extends NamedChannel>> broadcastPlanChannels,
List<PlanNode> target,
CostEstimator estimator,
RequestedGlobalProperties globPropsReq,
RequestedLocalProperties locPropsReq) {
// NOTES ON THE ENUMERATION OF THE STEP FUNCTION PLANS:
// Whenever we instantiate the iteration, we enumerate new candidates for the step function.
// That way, we make sure we have an appropriate plan for each candidate for the initial partial
// solution,
// we have a fitting candidate for the step function (often, work is pushed out of the step
// function).
// Among the candidates of the step function, we keep only those that meet the requested
// properties of the
// current candidate initial partial solution. That makes sure these properties exist at the
// beginning of
// the successive iteration.
// 1) Because we enumerate multiple times, we may need to clean the cached plans
// before starting another enumeration
this.nextPartialSolution.accept(PlanCacheCleaner.INSTANCE);
// 2) Give the partial solution the properties of the current candidate for the initial partial
// solution
this.partialSolution.setCandidateProperties(in.getGlobalProperties(), in.getLocalProperties());
final BulkPartialSolutionPlanNode pspn =
this.partialSolution.getCurrentPartialSolutionPlanNode();
// 3) Get the alternative plans
List<PlanNode> candidates = this.nextPartialSolution.getAlternativePlans(estimator);
// 4) Throw away all that are not compatible with the properties currently requested to the
// initial partial solution
for (Iterator<PlanNode> planDeleter = candidates.iterator(); planDeleter.hasNext(); ) {
PlanNode candidate = planDeleter.next();
if (!(globPropsReq.isMetBy(candidate.getGlobalProperties())
&& locPropsReq.isMetBy(candidate.getLocalProperties()))) {
planDeleter.remove();
}
}
// 5) Create a candidate for the Iteration Node for every remaining plan of the step function.
if (terminationCriterion == null) {
for (PlanNode candidate : candidates) {
BulkIterationPlanNode node =
new BulkIterationPlanNode(
this,
"BulkIteration (" + this.getPactContract().getName() + ")",
in,
pspn,
candidate);
GlobalProperties gProps = candidate.getGlobalProperties().clone();
LocalProperties lProps = candidate.getLocalProperties().clone();
node.initProperties(gProps, lProps);
target.add(node);
}
} else if (candidates.size() > 0) {
List<PlanNode> terminationCriterionCandidates =
this.terminationCriterion.getAlternativePlans(estimator);
for (PlanNode candidate : candidates) {
for (PlanNode terminationCandidate : terminationCriterionCandidates) {
if (this.singleRoot.areBranchCompatible(candidate, terminationCandidate)) {
BulkIterationPlanNode node =
new BulkIterationPlanNode(
this,
"BulkIteration (" + this.getPactContract().getName() + ")",
in,
pspn,
candidate,
terminationCandidate);
GlobalProperties gProps = candidate.getGlobalProperties().clone();
LocalProperties lProps = candidate.getLocalProperties().clone();
node.initProperties(gProps, lProps);
target.add(node);
}
}
}
}
}
/**
* This method computes the cost of an operator. The cost is composed of cost for input shipping,
* locally processing an input, and running the operator.
*
* <p>It requires at least that all inputs are set and have a proper ship strategy set, which is
* not equal to <tt>NONE</tt>.
*
* @param n The node to compute the costs for.
*/
public void costOperator(PlanNode n) {
// initialize costs objects with no costs
final Costs totalCosts = new Costs();
final long availableMemory = n.getGuaranteedAvailableMemory();
// add the shipping strategy costs
for (Iterator<Channel> channels = n.getInputs(); channels.hasNext(); ) {
final Channel channel = channels.next();
final Costs costs = new Costs();
// Plans that apply the same strategies, but at different points
// are equally expensive. For example, if a partitioning can be
// pushed below a Map function there is often no difference in plan
// costs between the pushed down version and the version that partitions
// after the Mapper. However, in those cases, we want the expensive
// strategy to appear later in the plan, as data reduction often occurs
// by large factors, while blowup is rare and typically by smaller fractions.
// We achieve this by adding a penalty to small penalty to the FORWARD strategy,
// weighted by the current plan depth (steps to the earliest data source).
// that way, later FORWARDS are more expensive than earlier forwards.
// Note that this only applies to the heuristic costs.
switch (channel.getShipStrategy()) {
case NONE:
throw new CompilerException(
"Cannot determine costs: Shipping strategy has not been set for an input.");
case FORWARD:
// costs.addHeuristicNetworkCost(channel.getMaxDepth());
break;
case PARTITION_LOCAL_HASH:
break;
case PARTITION_RANDOM:
addRandomPartitioningCost(channel, costs);
break;
case PARTITION_HASH:
addHashPartitioningCost(channel, costs);
break;
case PARTITION_RANGE:
addRangePartitionCost(channel, costs);
break;
case BROADCAST:
addBroadcastCost(channel, channel.getReplicationFactor(), costs);
break;
default:
throw new CompilerException(
"Unknown shipping strategy for input: " + channel.getShipStrategy());
}
switch (channel.getLocalStrategy()) {
case NONE:
break;
case SORT:
case COMBININGSORT:
addLocalSortCost(channel, availableMemory, costs);
break;
default:
throw new CompilerException(
"Unsupported local strategy for input: " + channel.getLocalStrategy());
}
if (channel.getTempMode() != null && channel.getTempMode() != TempMode.NONE) {
addArtificialDamCost(channel, 0, costs);
}
// adjust with the cost weight factor
if (channel.isOnDynamicPath()) {
costs.multiplyWith(channel.getCostWeight());
}
totalCosts.addCosts(costs);
}
Channel firstInput = null;
Channel secondInput = null;
Costs driverCosts = new Costs();
// get the inputs, if we have some
{
Iterator<Channel> channels = n.getInputs();
if (channels.hasNext()) firstInput = channels.next();
if (channels.hasNext()) secondInput = channels.next();
}
// determine the local costs
switch (n.getDriverStrategy()) {
case NONE:
case UNARY_NO_OP:
case BINARY_NO_OP:
case COLLECTOR_MAP:
case MAP:
case FLAT_MAP:
case ALL_GROUP:
// this operation does not do any actual grouping, since every element is in the same single
// group
case CO_GROUP:
case SORTED_GROUP:
// grouping or co-grouping over sorted streams for free
case PARTIAL_GROUP:
// partial grouping is always local and main memory resident. we should add a relative cpu
// cost at some point
case UNION:
// pipelined local union is for free
break;
case MERGE:
addLocalMergeCost(firstInput, secondInput, availableMemory, driverCosts);
break;
case HYBRIDHASH_BUILD_FIRST:
addHybridHashCosts(firstInput, secondInput, availableMemory, driverCosts);
break;
case HYBRIDHASH_BUILD_SECOND:
addHybridHashCosts(secondInput, firstInput, availableMemory, driverCosts);
break;
case NESTEDLOOP_BLOCKED_OUTER_FIRST:
addBlockNestedLoopsCosts(firstInput, secondInput, availableMemory, driverCosts);
break;
case NESTEDLOOP_BLOCKED_OUTER_SECOND:
addBlockNestedLoopsCosts(secondInput, firstInput, availableMemory, driverCosts);
break;
case NESTEDLOOP_STREAMED_OUTER_FIRST:
addStreamedNestedLoopsCosts(firstInput, secondInput, availableMemory, driverCosts);
break;
case NESTEDLOOP_STREAMED_OUTER_SECOND:
addStreamedNestedLoopsCosts(secondInput, firstInput, availableMemory, driverCosts);
break;
case GROUP_SELF_NESTEDLOOP:
default:
throw new CompilerException("Unknown local strategy: " + n.getDriverStrategy().name());
}
// adjust with the cost weight factor
if (n.isOnDynamicPath()) {
driverCosts.multiplyWith(n.getCostWeight());
}
totalCosts.addCosts(driverCosts);
n.setCosts(totalCosts);
}
public String toString() {
return original.toString();
}
@Override
protected void instantiate(
OperatorDescriptorDual operator,
Channel solutionSetIn,
Channel worksetIn,
List<Set<? extends NamedChannel>> broadcastPlanChannels,
List<PlanNode> target,
CostEstimator estimator,
RequestedGlobalProperties globPropsReqSolutionSet,
RequestedGlobalProperties globPropsReqWorkset,
RequestedLocalProperties locPropsReqSolutionSet,
RequestedLocalProperties locPropsReqWorkset) {
// check for pipeline breaking using hash join with build on the solution set side
placePipelineBreakersIfNecessary(
DriverStrategy.HYBRIDHASH_BUILD_FIRST, solutionSetIn, worksetIn);
// NOTES ON THE ENUMERATION OF THE STEP FUNCTION PLANS:
// Whenever we instantiate the iteration, we enumerate new candidates for the step function.
// That way, we make sure we have an appropriate plan for each candidate for the initial partial
// solution,
// we have a fitting candidate for the step function (often, work is pushed out of the step
// function).
// Among the candidates of the step function, we keep only those that meet the requested
// properties of the
// current candidate initial partial solution. That makes sure these properties exist at the
// beginning of
// every iteration.
// 1) Because we enumerate multiple times, we may need to clean the cached plans
// before starting another enumeration
this.nextWorkset.accept(PlanCacheCleaner.INSTANCE);
this.solutionSetDelta.accept(PlanCacheCleaner.INSTANCE);
// 2) Give the partial solution the properties of the current candidate for the initial partial
// solution
// This concerns currently only the workset.
this.worksetNode.setCandidateProperties(
worksetIn.getGlobalProperties(), worksetIn.getLocalProperties());
this.solutionSetNode.setCandidateProperties(this.partitionedProperties, new LocalProperties());
final SolutionSetPlanNode sspn = this.solutionSetNode.getCurrentSolutionSetPlanNode();
final WorksetPlanNode wspn = this.worksetNode.getCurrentWorksetPlanNode();
// 3) Get the alternative plans
List<PlanNode> solutionSetDeltaCandidates =
this.solutionSetDelta.getAlternativePlans(estimator);
List<PlanNode> worksetCandidates = this.nextWorkset.getAlternativePlans(estimator);
// 4) Throw away all that are not compatible with the properties currently requested to the
// initial partial solution
// Make sure that the workset candidates fulfill the input requirements
for (Iterator<PlanNode> planDeleter = worksetCandidates.iterator(); planDeleter.hasNext(); ) {
PlanNode candidate = planDeleter.next();
if (!(globPropsReqWorkset.isMetBy(candidate.getGlobalProperties())
&& locPropsReqWorkset.isMetBy(candidate.getLocalProperties()))) {
planDeleter.remove();
}
}
if (worksetCandidates.isEmpty()) {
return;
}
// sanity check the solution set delta and cancel out the delta node, if it is not needed
for (Iterator<PlanNode> deltaPlans = solutionSetDeltaCandidates.iterator();
deltaPlans.hasNext(); ) {
SingleInputPlanNode candidate = (SingleInputPlanNode) deltaPlans.next();
GlobalProperties gp = candidate.getGlobalProperties();
if (gp.getPartitioning() != PartitioningProperty.HASH_PARTITIONED
|| gp.getPartitioningFields() == null
|| !gp.getPartitioningFields().equals(this.solutionSetKeyFields)) {
throw new CompilerException("Bug: The solution set delta is not partitioned.");
}
}
// 5) Create a candidate for the Iteration Node for every remaining plan of the step function.
final GlobalProperties gp = new GlobalProperties();
gp.setHashPartitioned(this.solutionSetKeyFields);
gp.addUniqueFieldCombination(this.solutionSetKeyFields);
final LocalProperties lp = new LocalProperties();
lp.addUniqueFields(this.solutionSetKeyFields);
// take all combinations of solution set delta and workset plans
for (PlanNode solutionSetCandidate : solutionSetDeltaCandidates) {
for (PlanNode worksetCandidate : worksetCandidates) {
// check whether they have the same operator at their latest branching point
if (this.singleRoot.areBranchCompatible(solutionSetCandidate, worksetCandidate)) {
SingleInputPlanNode siSolutionDeltaCandidate = (SingleInputPlanNode) solutionSetCandidate;
boolean immediateDeltaUpdate;
// check whether we need a dedicated solution set delta operator, or whether we can update
// on the fly
if (siSolutionDeltaCandidate.getInput().getShipStrategy() == ShipStrategyType.FORWARD
&& this.solutionDeltaImmediatelyAfterSolutionJoin) {
// we do not need this extra node. we can make the predecessor the delta
// sanity check the node and connection
if (siSolutionDeltaCandidate.getDriverStrategy() != DriverStrategy.UNARY_NO_OP
|| siSolutionDeltaCandidate.getInput().getLocalStrategy() != LocalStrategy.NONE) {
throw new CompilerException("Invalid Solution set delta node.");
}
solutionSetCandidate = siSolutionDeltaCandidate.getInput().getSource();
immediateDeltaUpdate = true;
} else {
// was not partitioned, we need to keep this node.
// mark that we materialize the input
siSolutionDeltaCandidate.getInput().setTempMode(TempMode.PIPELINE_BREAKER);
immediateDeltaUpdate = false;
}
WorksetIterationPlanNode wsNode =
new WorksetIterationPlanNode(
this,
"WorksetIteration (" + this.getPactContract().getName() + ")",
solutionSetIn,
worksetIn,
sspn,
wspn,
worksetCandidate,
solutionSetCandidate);
wsNode.setImmediateSolutionSetUpdate(immediateDeltaUpdate);
wsNode.initProperties(gp, lp);
target.add(wsNode);
}
}
}
}
