presto-main/src/main/java/io/prestosql/execution/resourcegroups/InternalResourceGroup.java/InternalResourceGroup/startInBackground
class InternalResourceGroup:    private void startInBackground(ManagedQueryExecution query)
    {
        checkState(Thread.holdsLock(root), "Must hold lock to start a query");
        synchronized (root) {
            runningQueries.put(query, new ResourceUsage(0, 0));
            InternalResourceGroup group = this;
            while (group.parent.isPresent()) {
                group.parent.get().descendantRunningQueries++;
                group.parent.get().dirtySubGroups.add(group);
                group = group.parent.get();
            }
            updateEligibility();
            executor.execute(query::startWaitingForResources);
        }
    }