/**
* Helper method for parallelizing a given fragment. Dependent fragments are parallelized first
* before parallelizing the given fragment.
*/
private void parallelizeFragment(
Wrapper fragmentWrapper,
PlanningSet planningSet,
Collection<DrillbitEndpoint> activeEndpoints)
throws PhysicalOperatorSetupException {
// If the fragment is already parallelized, return.
if (fragmentWrapper.isEndpointsAssignmentDone()) {
return;
}
// First parallelize fragments on which this fragment depends on.
final List<Wrapper> fragmentDependencies = fragmentWrapper.getFragmentDependencies();
if (fragmentDependencies != null && fragmentDependencies.size() > 0) {
for (Wrapper dependency : fragmentDependencies) {
parallelizeFragment(dependency, planningSet, activeEndpoints);
}
}
// Find stats. Stats include various factors including cost of physical operators,
// parallelizability of
// work in physical operator and affinity of physical operator to certain nodes.
fragmentWrapper.getNode().getRoot().accept(new StatsCollector(planningSet), fragmentWrapper);
fragmentWrapper
.getStats()
.getDistributionAffinity()
.getFragmentParallelizer()
.parallelizeFragment(fragmentWrapper, this, activeEndpoints);
}
/**
* Helper method to reuse the code for QueryWorkUnit(s) generation
*
* @param activeEndpoints
* @param rootFragment
* @return
* @throws ExecutionSetupException
*/
protected PlanningSet getFragmentsHelper(
Collection<DrillbitEndpoint> activeEndpoints, Fragment rootFragment)
throws ExecutionSetupException {
PlanningSet planningSet = new PlanningSet();
initFragmentWrappers(rootFragment, planningSet);
final Set<Wrapper> leafFragments = constructFragmentDependencyGraph(planningSet);
// Start parallelizing from leaf fragments
for (Wrapper wrapper : leafFragments) {
parallelizeFragment(wrapper, planningSet, activeEndpoints);
}
return planningSet;
}