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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.drill.exec.planner.fragment.contrib;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.drill.common.exceptions.ExecutionSetupException;
import org.apache.drill.common.util.DrillStringUtils;
import org.apache.drill.exec.ops.QueryContext;
import org.apache.drill.exec.physical.base.Exchange;
import org.apache.drill.exec.physical.base.FragmentRoot;
import org.apache.drill.exec.physical.base.PhysicalOperator;
import org.apache.drill.exec.planner.PhysicalPlanReader;
import org.apache.drill.exec.planner.fragment.Fragment;
import org.apache.drill.exec.planner.fragment.PlanningSet;
import org.apache.drill.exec.planner.fragment.SimpleParallelizer;
import org.apache.drill.exec.planner.fragment.Wrapper;
import org.apache.drill.exec.planner.fragment.Materializer.IndexedFragmentNode;
import org.apache.drill.exec.proto.BitControl.PlanFragment;
import org.apache.drill.exec.proto.BitControl.QueryContextInformation;
import org.apache.drill.exec.proto.CoordinationProtos.DrillbitEndpoint;
import org.apache.drill.exec.proto.ExecProtos.FragmentHandle;
import org.apache.drill.exec.proto.UserBitShared.QueryId;
import org.apache.drill.exec.rpc.user.UserSession;
import org.apache.drill.exec.server.options.OptionList;
import org.apache.drill.exec.work.QueryWorkUnit;
import org.apache.drill.exec.work.QueryWorkUnit.MinorFragmentDefn;
import org.apache.drill.exec.work.foreman.ForemanSetupException;
import org.apache.drill.shaded.guava.com.google.common.base.Preconditions;
import org.apache.drill.shaded.guava.com.google.common.collect.Lists;
/**
* SimpleParallelizerMultiPlans class is an extension to SimpleParallelizer
* to help with getting PlanFragments for split plan.
* Split plan is essentially ability to create multiple Physical Operator plans from original Physical Operator plan
* to be able to run plans separately.
* Moving functionality specific to splitting the plan to this class
* allows not to pollute parent class with non-authentic functionality
*
*/
public class SplittingParallelizer extends SimpleParallelizer {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SplittingParallelizer.class);
public SplittingParallelizer(QueryContext context) {
super(context);
}
/**
* Create multiple physical plans from original query planning, it will allow execute them eventually independently
* @param options
* @param foremanNode
* @param queryId
* @param activeEndpoints
* @param reader
* @param rootFragment
* @param session
* @param queryContextInfo
* @return
* @throws ExecutionSetupException
*/
public List<QueryWorkUnit> getSplitFragments(OptionList options, DrillbitEndpoint foremanNode, QueryId queryId,
Collection<DrillbitEndpoint> activeEndpoints, PhysicalPlanReader reader, Fragment rootFragment,
UserSession session, QueryContextInformation queryContextInfo) throws ExecutionSetupException {
final PlanningSet planningSet = getFragmentsHelper(activeEndpoints, rootFragment);
return generateWorkUnits(
options, foremanNode, queryId, reader, rootFragment, planningSet, session, queryContextInfo);
}
/**
* Split plan into multiple plans based on parallelization
* Ideally it is applicable only to plans with two major fragments: Screen and UnionExchange
* But there could be cases where we can remove even multiple exchanges like in case of "order by"
* End goal is to get single major fragment: Screen with chain that ends up with a single minor fragment
* from Leaf Exchange. This way each plan can run independently without any exchange involvement
* @param options
* @param foremanNode - not really applicable
* @param queryId
* @param reader
* @param rootNode
* @param planningSet
* @param session
* @param queryContextInfo
* @return
* @throws ExecutionSetupException
*/
private List<QueryWorkUnit> generateWorkUnits(OptionList options, DrillbitEndpoint foremanNode, QueryId queryId,
PhysicalPlanReader reader, Fragment rootNode, PlanningSet planningSet,
UserSession session, QueryContextInformation queryContextInfo) throws ExecutionSetupException {
// now we generate all the individual plan fragments and associated assignments. Note, we need all endpoints
// assigned before we can materialize, so we start a new loop here rather than utilizing the previous one.
List<QueryWorkUnit> workUnits = Lists.newArrayList();
int plansCount = 0;
DrillbitEndpoint[] endPoints = null;
long initialAllocation = 0;
final Iterator<Wrapper> iter = planningSet.iterator();
while (iter.hasNext()) {
Wrapper wrapper = iter.next();
Fragment node = wrapper.getNode();
boolean isLeafFragment = node.getReceivingExchangePairs().size() == 0;
final PhysicalOperator physicalOperatorRoot = node.getRoot();
// get all the needed info from leaf fragment
if ( (physicalOperatorRoot instanceof Exchange) && isLeafFragment) {
// need to get info about
// number of minor fragments
// assignedEndPoints
// allocation
plansCount = wrapper.getWidth();
initialAllocation = (wrapper.getInitialAllocation() != 0 ) ? wrapper.getInitialAllocation()/plansCount : 0;
endPoints = new DrillbitEndpoint[plansCount];
for (int mfId = 0; mfId < plansCount; mfId++) {
endPoints[mfId] = wrapper.getAssignedEndpoint(mfId);
}
}
}
if ( plansCount == 0 ) {
// no exchange, return list of single QueryWorkUnit
workUnits.add(generateWorkUnit(options, foremanNode, queryId, rootNode, planningSet, session, queryContextInfo));
return workUnits;
}
for (Wrapper wrapper : planningSet) {
Fragment node = wrapper.getNode();
final PhysicalOperator physicalOperatorRoot = node.getRoot();
if ( physicalOperatorRoot instanceof Exchange ) {
// get to 0 MajorFragment
continue;
}
boolean isRootNode = rootNode == node;
if (isRootNode && wrapper.getWidth() != 1) {
throw new ForemanSetupException(String.format("Failure while trying to setup fragment. " +
"The root fragment must always have parallelization one. In the current case, the width was set to %d.",
wrapper.getWidth()));
}
// this fragment is always leaf, as we are removing all the exchanges
boolean isLeafFragment = true;
FragmentHandle handle = FragmentHandle //
.newBuilder() //
.setMajorFragmentId(wrapper.getMajorFragmentId()) //
.setMinorFragmentId(0) // minor fragment ID is going to be always 0, as plan will be split
.setQueryId(queryId) //
.build();
// Create a minorFragment for each major fragment.
for (int minorFragmentId = 0; minorFragmentId < plansCount; minorFragmentId++) {
// those fragments should be empty
List<MinorFragmentDefn> fragments = Lists.newArrayList();
MinorFragmentDefn rootFragment = null;
FragmentRoot rootOperator = null;
IndexedFragmentNode iNode = new IndexedFragmentNode(minorFragmentId, wrapper);
wrapper.resetAllocation();
// two visitors here
// 1. To remove exchange
// 2. To reset operator IDs as exchanges were removed
PhysicalOperator op = physicalOperatorRoot.accept(ExchangeRemoverMaterializer.INSTANCE, iNode).
accept(OperatorIdVisitor.INSTANCE, 0);
Preconditions.checkArgument(op instanceof FragmentRoot);
FragmentRoot root = (FragmentRoot) op;
PlanFragment fragment = PlanFragment.newBuilder() //
.setForeman(endPoints[minorFragmentId]) //
.setHandle(handle) //
.setAssignment(endPoints[minorFragmentId]) //
.setLeafFragment(isLeafFragment) //
.setContext(queryContextInfo)
.setMemInitial(initialAllocation)//
.setMemMax(wrapper.getMaxAllocation()) // TODO - for some reason OOM is using leaf fragment max allocation divided by width
.setCredentials(session.getCredentials())
.addAllCollector(CountRequiredFragments.getCollectors(root))
.build();
MinorFragmentDefn fragmentDefn = new MinorFragmentDefn(fragment, root, options);
if (isRootNode) {
if (logger.isDebugEnabled()) {
logger.debug("Root fragment:\n {}", DrillStringUtils.unescapeJava(fragment.toString()));
}
rootFragment = fragmentDefn;
rootOperator = root;
} else {
if (logger.isDebugEnabled()) {
logger.debug("Remote fragment:\n {}", DrillStringUtils.unescapeJava(fragment.toString()));
}
throw new ForemanSetupException(String.format("There should not be non-root/remote fragment present in plan split, but there is:",
DrillStringUtils.unescapeJava(fragment.toString())));
}
// fragments should be always empty here
workUnits.add(new QueryWorkUnit(rootOperator, rootFragment, fragments, planningSet.getRootWrapper()));
}
}
return workUnits;
}
}
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