/*
* 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.pig.pen;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pig.backend.executionengine.ExecException;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.plans.PhysicalPlan;
import org.apache.pig.data.BagFactory;
import org.apache.pig.data.DataBag;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.PigContext;
import org.apache.pig.impl.logicalLayer.LOCogroup;
import org.apache.pig.impl.logicalLayer.LOCross;
import org.apache.pig.impl.logicalLayer.LODistinct;
import org.apache.pig.impl.logicalLayer.LOFilter;
import org.apache.pig.impl.logicalLayer.LOForEach;
import org.apache.pig.impl.logicalLayer.LOLimit;
import org.apache.pig.impl.logicalLayer.LOLoad;
import org.apache.pig.impl.logicalLayer.LOSort;
import org.apache.pig.impl.logicalLayer.LOSplit;
import org.apache.pig.impl.logicalLayer.LOUnion;
import org.apache.pig.impl.logicalLayer.LOVisitor;
import org.apache.pig.impl.logicalLayer.LogicalOperator;
import org.apache.pig.impl.logicalLayer.LogicalPlan;
import org.apache.pig.impl.plan.VisitorException;
import org.apache.pig.impl.util.IdentityHashSet;
import org.apache.pig.pen.util.LineageTracer;
import org.apache.pig.pen.util.MetricEvaluation;
import org.apache.pig.pen.util.PreOrderDepthFirstWalker;
public class LineageTrimmingVisitor extends LOVisitor {
LogicalPlan plan = null;
Map<LOLoad, DataBag> baseData = new HashMap<LOLoad, DataBag>();
Map<LogicalOperator, PhysicalOperator> LogToPhyMap = null;
PhysicalPlan physPlan = null;
double completeness = 100.0;
Log log = LogFactory.getLog(getClass());
Map<LogicalOperator, Map<IdentityHashSet<Tuple>, Integer>> AffinityGroups = new HashMap<LogicalOperator, Map<IdentityHashSet<Tuple>, Integer>>();
Map<LogicalOperator, LineageTracer> Lineage = new HashMap<LogicalOperator, LineageTracer>();
boolean continueTrimming;
PigContext pc;
public LineageTrimmingVisitor(LogicalPlan plan,
Map<LOLoad, DataBag> baseData,
Map<LogicalOperator, PhysicalOperator> LogToPhyMap,
PhysicalPlan physPlan, PigContext pc) {
super(plan, new PreOrderDepthFirstWalker<LogicalOperator, LogicalPlan>(
plan));
// this.baseData.putAll(baseData);
this.baseData = baseData;
this.plan = plan;
this.LogToPhyMap = LogToPhyMap;
this.pc = pc;
this.physPlan = physPlan;
init();
}
public void init() {
DerivedDataVisitor visitor = new DerivedDataVisitor(plan, pc, baseData,
LogToPhyMap, physPlan);
try {
visitor.visit();
} catch (VisitorException e) {
log.error(e.getMessage());
}
LineageTracer lineage = visitor.lineage;
Lineage.put(plan.getLeaves().get(0), lineage);
Map<LogicalOperator, Collection<IdentityHashSet<Tuple>>> OpToEqClasses = visitor.OpToEqClasses;
Collection<IdentityHashSet<Tuple>> EqClasses = visitor.EqClasses;
Map<IdentityHashSet<Tuple>, Integer> affinityGroup = new HashMap<IdentityHashSet<Tuple>, Integer>();
for (IdentityHashSet<Tuple> set : EqClasses) {
affinityGroup.put(set, 1);
}
AffinityGroups.put(plan.getLeaves().get(0), affinityGroup);
completeness = MetricEvaluation.getCompleteness(null,
visitor.derivedData, OpToEqClasses, true);
LogToPhyMap = visitor.LogToPhyMap;
continueTrimming = true;
}
@Override
protected void visit(LOCogroup cg) throws VisitorException {
if (continueTrimming) {
Map<IdentityHashSet<Tuple>, Integer> affinityGroups = null;
continueTrimming = checkCompleteness(cg);
DerivedDataVisitor visitor = null;
LineageTracer lineage = null;
// create affinity groups
if (cg.getInputs().size() == 1) {
affinityGroups = new HashMap<IdentityHashSet<Tuple>, Integer>();
LogicalOperator childOp = cg.getInputs().get(0);
visitor = new DerivedDataVisitor(childOp, null, baseData,
LogToPhyMap, physPlan);
try {
visitor.visit();
} catch (VisitorException e) {
log.error(e.getMessage());
}
lineage = visitor.lineage;
DataBag bag = visitor.evaluateIsolatedOperator(cg);
for (Iterator<Tuple> it = bag.iterator(); it.hasNext();) {
DataBag field;
try {
field = (DataBag) it.next().get(1);
} catch (ExecException e) {
// TODO Auto-generated catch block
e.printStackTrace();
log.error(e.getMessage());
throw new VisitorException(
"Error trimming operator COGROUP operator "
+ cg.getAlias()
+ "in example generator");
}
IdentityHashSet<Tuple> set = new IdentityHashSet<Tuple>();
affinityGroups.put(set, 2);
for (Iterator<Tuple> it1 = field.iterator(); it1.hasNext();) {
set.add(it1.next());
}
}
// add the equivalence classes obtained from derived data
// creation
for (IdentityHashSet<Tuple> set : visitor.EqClasses) {
affinityGroups.put(set, 1);
}
AffinityGroups.put(cg.getInputs().get(0), affinityGroups);
Lineage.put(cg.getInputs().get(0), lineage);
} else {
List<DataBag> inputs = new LinkedList<DataBag>();
visitor = new DerivedDataVisitor(cg, null, baseData,
LogToPhyMap, physPlan);
affinityGroups = new HashMap<IdentityHashSet<Tuple>, Integer>();
for (int i = 0; i < cg.getInputs().size(); i++) {
// affinityGroups = new HashMap<IdentityHashSet<Tuple>,
// Integer>();
LogicalOperator childOp = cg.getInputs().get(i);
// visitor = new DerivedDataVisitor(cg.getInputs().get(i),
// null, baseData, LogToPhyMap, physPlan);
visitor.setOperatorToEvaluate(childOp);
try {
visitor.visit();
} catch (VisitorException e) {
log.error(e.getMessage());
}
// Lineage.put(childOp, visitor.lineage);
inputs.add(visitor.derivedData.get(childOp));
for (IdentityHashSet<Tuple> set : visitor.EqClasses)
affinityGroups.put(set, 1);
// AffinityGroups.put(cg.getInputs().get(i),
// affinityGroups);
}
for (LogicalOperator input : cg.getInputs()) {
Lineage.put(input, visitor.lineage);
AffinityGroups.put(input, affinityGroups);
}
visitor = new DerivedDataVisitor(cg, null, baseData,
LogToPhyMap, physPlan);
DataBag output = visitor.evaluateIsolatedOperator(cg, inputs);
for (int i = 1; i <= cg.getInputs().size(); i++) {
affinityGroups = new HashMap<IdentityHashSet<Tuple>, Integer>();
for (Iterator<Tuple> it = output.iterator(); it.hasNext();) {
DataBag bag = null;
try {
bag = (DataBag) it.next().get(i);
} catch (ExecException e) {
// TODO Auto-generated catch block
log.error(e.getMessage());
}
IdentityHashSet<Tuple> set = new IdentityHashSet<Tuple>();
affinityGroups.put(set, 1);
for (Iterator<Tuple> it1 = bag.iterator(); it1
.hasNext();) {
set.add(it1.next());
}
}
AffinityGroups.get(cg.getInputs().get(i - 1)).putAll(
affinityGroups);
}
AffinityGroups = AffinityGroups;
}
}
}
@Override
protected void visit(LOCross cs) throws VisitorException {
if(continueTrimming)
processOperator(cs);
}
@Override
protected void visit(LODistinct dt) throws VisitorException {
if(continueTrimming)
processOperator(dt);
}
@Override
protected void visit(LOFilter filter) throws VisitorException {
if (continueTrimming)
processOperator(filter);
}
@Override
protected void visit(LOForEach forEach) throws VisitorException {
if (continueTrimming)
processOperator(forEach);
}
@Override
protected void visit(LOLimit limOp) throws VisitorException {
if(continueTrimming)
processOperator(limOp);
}
@Override
protected void visit(LOLoad load) throws VisitorException {
if (continueTrimming)
processOperator(load);
}
@Override
protected void visit(LOSort s) throws VisitorException {
if(continueTrimming)
processOperator(s);
}
@Override
protected void visit(LOSplit split) throws VisitorException {
if(continueTrimming)
processOperator(split);
}
@Override
protected void visit(LOUnion u) throws VisitorException {
if(continueTrimming)
processOperator(u);
}
private Map<LOLoad, DataBag> PruneBaseDataConstrainedCoverage(
Map<LOLoad, DataBag> baseData, DataBag rootOutput,
LineageTracer lineage,
Map<IdentityHashSet<Tuple>, Integer> equivalenceClasses) {
IdentityHashMap<Tuple, Collection<Tuple>> membershipMap = lineage
.getMembershipMap();
IdentityHashMap<Tuple, Double> lineageGroupWeights = lineage
.getWeightedCounts(2f, 1);
// compute a mapping from lineage group to the set of equivalence
// classes covered by it
// IdentityHashMap<Tuple, Set<Integer>> lineageGroupToEquivClasses = new
// IdentityHashMap<Tuple, Set<Integer>>();
IdentityHashMap<Tuple, Set<IdentityHashSet<Tuple>>> lineageGroupToEquivClasses = new IdentityHashMap<Tuple, Set<IdentityHashSet<Tuple>>>();
int equivClassId = 0;
for (IdentityHashSet<Tuple> equivClass : equivalenceClasses.keySet()) {
for (Tuple t : equivClass) {
Tuple lineageGroup = lineage.getRepresentative(t);
// Set<Integer> entry =
// lineageGroupToEquivClasses.get(lineageGroup);
Set<IdentityHashSet<Tuple>> entry = lineageGroupToEquivClasses
.get(lineageGroup);
if (entry == null) {
// entry = new HashSet<Integer>();
entry = new HashSet<IdentityHashSet<Tuple>>();
lineageGroupToEquivClasses.put(lineageGroup, entry);
}
// entry.add(equivClassId);
entry.add(equivClass);
}
equivClassId++;
}
// select lineage groups such that we cover all equivalence classes
IdentityHashSet<Tuple> selectedLineageGroups = new IdentityHashSet<Tuple>();
while (!lineageGroupToEquivClasses.isEmpty()) {
// greedily find the lineage group with the best "score", where
// score = # equiv classes covered / group weight
double bestScore = -1;
Tuple bestLineageGroup = null;
Set<IdentityHashSet<Tuple>> bestEquivClassesCovered = null;
for (Tuple lineageGroup : lineageGroupToEquivClasses.keySet()) {
double weight = lineageGroupWeights.get(lineageGroup);
Set<IdentityHashSet<Tuple>> equivClassesCovered = lineageGroupToEquivClasses
.get(lineageGroup);
int numEquivClassesCovered = equivClassesCovered.size();
double score = ((double) numEquivClassesCovered) / weight;
if (score > bestScore) {
if (selectedLineageGroups.contains(lineageGroup)) {
bestLineageGroup = lineageGroup;
bestEquivClassesCovered = equivClassesCovered;
continue;
}
bestScore = score;
bestLineageGroup = lineageGroup;
bestEquivClassesCovered = equivClassesCovered;
}
}
// add the best-scoring lineage group to the set of ones we plan to
// retain
selectedLineageGroups.add(bestLineageGroup);
// make copy of bestEquivClassesCovered (or else the code that
// follows won't work correctly, because removing from the reference
// set)
Set<IdentityHashSet<Tuple>> toCopy = bestEquivClassesCovered;
bestEquivClassesCovered = new HashSet<IdentityHashSet<Tuple>>();
bestEquivClassesCovered.addAll(toCopy);
// remove the classes we've now covered
Collection<Tuple> toRemove = new LinkedList<Tuple>();
for (Tuple lineageGroup : lineageGroupToEquivClasses.keySet()) {
Set<IdentityHashSet<Tuple>> equivClasses = lineageGroupToEquivClasses
.get(lineageGroup);
for (Iterator<IdentityHashSet<Tuple>> it = equivClasses
.iterator(); it.hasNext();) {
IdentityHashSet<Tuple> equivClass = it.next();
if (bestEquivClassesCovered.contains(equivClass)) {
if ((equivalenceClasses.get(equivClass) - 1) <= 0) {
// equivClasses.remove(equivClass);
it.remove();
}
}
}
if (equivClasses.size() == 0)
toRemove.add(lineageGroup);
}
for (Tuple removeMe : toRemove)
lineageGroupToEquivClasses.remove(removeMe);
for (IdentityHashSet<Tuple> equivClass : bestEquivClassesCovered) {
equivalenceClasses.put(equivClass, equivalenceClasses
.get(equivClass) - 1);
}
}
// revise baseData to only contain the tuples that are part of
// selectedLineageGroups
IdentityHashSet<Tuple> tuplesToRetain = new IdentityHashSet<Tuple>();
for (Tuple lineageGroup : selectedLineageGroups) {
Collection<Tuple> members = membershipMap.get(lineageGroup);
for (Tuple t : members)
tuplesToRetain.add(t);
}
Map<LOLoad, DataBag> newBaseData = new HashMap<LOLoad, DataBag>();
for (LOLoad loadOp : baseData.keySet()) {
DataBag data = baseData.get(loadOp);
// DataBag newData = new DataBag();
DataBag newData = BagFactory.getInstance().newDefaultBag();
for (Iterator<Tuple> it = data.iterator(); it.hasNext();) {
Tuple t = it.next();
if (tuplesToRetain.contains(t))
newData.add(t);
}
newBaseData.put(loadOp, newData);
}
return newBaseData;
}
private void processOperator(LogicalOperator op) {
if (op instanceof LOLoad) return;
continueTrimming = checkCompleteness(op);
if (continueTrimming == false)
return;
LogicalOperator childOp = plan.getPredecessors(op).get(0);
DerivedDataVisitor visitor = new DerivedDataVisitor(childOp, null,
baseData, LogToPhyMap, physPlan);
try {
visitor.visit();
} catch (VisitorException e) {
log.error(e.getMessage());
}
DataBag bag = visitor.derivedData.get(childOp);
Map<IdentityHashSet<Tuple>, Integer> affinityGroups = new HashMap<IdentityHashSet<Tuple>, Integer>();
for (Iterator<Tuple> it = bag.iterator(); it.hasNext();) {
IdentityHashSet<Tuple> set = new IdentityHashSet<Tuple>();
affinityGroups.put(set, 1);
set.add(it.next());
}
for (IdentityHashSet<Tuple> set : visitor.EqClasses) {
// newEquivalenceClasses.put(set, 1);
affinityGroups.put(set, 1);
}
AffinityGroups.put(childOp, affinityGroups);
Lineage.put(childOp, visitor.lineage);
}
private boolean checkCompleteness(LogicalOperator op) {
LineageTracer lineage = Lineage.get(op);
Lineage.remove(op);
Map<IdentityHashSet<Tuple>, Integer> affinityGroups = AffinityGroups
.get(op);
AffinityGroups.remove(op);
Map<LOLoad, DataBag> newBaseData = PruneBaseDataConstrainedCoverage(
baseData, null, lineage, affinityGroups);
// obtain the derived data
DerivedDataVisitor visitor = new DerivedDataVisitor(plan, null,
newBaseData, LogToPhyMap, physPlan);
try {
visitor.visit();
} catch (VisitorException e) {
log.error(e.getMessage());
}
double newCompleteness = MetricEvaluation.getCompleteness(null,
visitor.derivedData, visitor.OpToEqClasses, true);
if (newCompleteness >= completeness) {
completeness = newCompleteness;
baseData.putAll(newBaseData);
} else {
continueTrimming = false;
}
return continueTrimming;
}
}