/**
* @param rearrange
* @return
*/
private static POPreCombinerLocalRearrange getPreCombinerLR(POLocalRearrange rearrange) {
String scope = rearrange.getOperatorKey().scope;
POPreCombinerLocalRearrange pclr =
new POPreCombinerLocalRearrange(
createOperatorKey(scope), rearrange.getRequestedParallelism(), rearrange.getInputs());
pclr.setPlans(rearrange.getPlans());
return pclr;
}
@Test
public void testMergeJoin() throws Exception {
String query =
"a = load '/tmp/input1';"
+ "b = load '/tmp/input2';"
+ "c = join a by $0, b by $0 using 'merge';"
+ "store c into '/tmp/output1';";
PhysicalPlan pp = Util.buildPp(pigServer, query);
MRCompiler comp = new MRCompiler(pp, pc);
comp.compile();
MROperPlan mrp = comp.getMRPlan();
assertTrue(mrp.size() == 2);
MapReduceOper mrOp0 = mrp.getRoots().get(0);
assertTrue(mrOp0.mapPlan.size() == 2);
PhysicalOperator load0 = mrOp0.mapPlan.getRoots().get(0);
MergeJoinIndexer func =
(MergeJoinIndexer)
PigContext.instantiateFuncFromSpec(((POLoad) load0).getLFile().getFuncSpec());
Field lrField = MergeJoinIndexer.class.getDeclaredField("lr");
lrField.setAccessible(true);
POLocalRearrange lr = (POLocalRearrange) lrField.get(func);
List<PhysicalPlan> innerPlans = lr.getPlans();
PhysicalOperator localrearrange0 = mrOp0.mapPlan.getSuccessors(load0).get(0);
assertTrue(localrearrange0 instanceof POLocalRearrange);
assertTrue(mrOp0.reducePlan.size() == 3);
PhysicalOperator pack0 = mrOp0.reducePlan.getRoots().get(0);
assertTrue(pack0 instanceof POPackage);
PhysicalOperator foreach0 = mrOp0.reducePlan.getSuccessors(pack0).get(0);
assertTrue(foreach0 instanceof POForEach);
PhysicalOperator store0 = mrOp0.reducePlan.getSuccessors(foreach0).get(0);
assertTrue(store0 instanceof POStore);
assertTrue(innerPlans.size() == 1);
PhysicalPlan innerPlan = innerPlans.get(0);
assertTrue(innerPlan.size() == 1);
PhysicalOperator project = innerPlan.getRoots().get(0);
assertTrue(project instanceof POProject);
assertTrue(((POProject) project).getColumn() == 0);
MapReduceOper mrOp1 = mrp.getSuccessors(mrOp0).get(0);
assertTrue(mrOp1.mapPlan.size() == 3);
PhysicalOperator load1 = mrOp1.mapPlan.getRoots().get(0);
assertTrue(load1 instanceof POLoad);
PhysicalOperator mergejoin1 = mrOp1.mapPlan.getSuccessors(load1).get(0);
assertTrue(mergejoin1 instanceof POMergeJoin);
PhysicalOperator store1 = mrOp1.mapPlan.getSuccessors(mergejoin1).get(0);
assertTrue(store1 instanceof POStore);
assertTrue(mrOp1.reducePlan.isEmpty());
}
/**
* create new Local rearrange by cloning existing rearrange and add plan for projecting the key
*
* @param rearrange
* @return
* @throws PlanException
* @throws CloneNotSupportedException
*/
private static POLocalRearrange getNewRearrange(POLocalRearrange rearrange)
throws PlanException, CloneNotSupportedException {
POLocalRearrange newRearrange = rearrange.clone();
// Set the projection to be the key
PhysicalPlan newPlan = new PhysicalPlan();
String scope = newRearrange.getOperatorKey().scope;
POProject proj =
new POProject(
new OperatorKey(scope, NodeIdGenerator.getGenerator().getNextNodeId(scope)), -1, 0);
proj.setResultType(newRearrange.getKeyType());
newPlan.add(proj);
List<PhysicalPlan> plans = new ArrayList<PhysicalPlan>(1);
plans.add(newPlan);
newRearrange.setPlansFromCombiner(plans);
return newRearrange;
}
@Override
public void visitLocalRearrange(POLocalRearrange lrearrange) throws VisitorException {
POLocalRearrangeTez lr = (POLocalRearrangeTez) lrearrange;
if (!(lr.isConnectedToPackage()
&& lr.getOutputKey().equals(pkgTezOp.getOperatorKey().toString()))) {
return;
}
loRearrangeFound++;
Map<Integer, Pair<Boolean, Map<Integer, Integer>>> keyInfo;
if (pkg.getPkgr() instanceof LitePackager) {
if (lrearrange.getIndex() != 0) {
// Throw some exception here
throw new RuntimeException(
"POLocalRearrange for POPackageLite cannot have index other than 0, but has index - "
+ lrearrange.getIndex());
}
}
// annotate the package with information from the LORearrange
// update the keyInfo information if already present in the POPackage
keyInfo = pkg.getPkgr().getKeyInfo();
if (keyInfo == null) keyInfo = new HashMap<Integer, Pair<Boolean, Map<Integer, Integer>>>();
if (keyInfo.get(Integer.valueOf(lrearrange.getIndex())) != null) {
// something is wrong - we should not be getting key info
// for the same index from two different Local Rearranges
int errCode = 2087;
String msg =
"Unexpected problem during optimization."
+ " Found index:"
+ lrearrange.getIndex()
+ " in multiple LocalRearrange operators.";
throw new OptimizerException(msg, errCode, PigException.BUG);
}
keyInfo.put(
Integer.valueOf(lrearrange.getIndex()),
new Pair<Boolean, Map<Integer, Integer>>(
lrearrange.isProjectStar(), lrearrange.getProjectedColsMap()));
pkg.getPkgr().setKeyInfo(keyInfo);
pkg.getPkgr().setKeyTuple(lrearrange.isKeyTuple());
pkg.getPkgr().setKeyCompound(lrearrange.isKeyCompound());
}
@Test
public void testSpl3() throws Exception {
PhysicalPlan php = new PhysicalPlan();
POLoad lA = GenPhyOp.topLoadOp();
POSplit spl = GenPhyOp.topSplitOp();
php.add(lA);
php.add(spl);
php.connect(lA, spl);
POFilter fl1 = GenPhyOp.topFilterOp();
fl1.setRequestedParallelism(10);
POFilter fl2 = GenPhyOp.topFilterOp();
fl2.setRequestedParallelism(20);
php.add(fl1);
php.add(fl2);
php.connect(spl, fl1);
php.connect(spl, fl2);
POSplit sp11 = GenPhyOp.topSplitOp();
POSplit sp21 = GenPhyOp.topSplitOp();
php.add(sp11);
php.add(sp21);
php.connect(fl1, sp11);
php.connect(fl2, sp21);
POFilter fl11 = GenPhyOp.topFilterOp();
fl11.setRequestedParallelism(10);
POFilter fl21 = GenPhyOp.topFilterOp();
fl21.setRequestedParallelism(20);
POFilter fl22 = GenPhyOp.topFilterOp();
fl22.setRequestedParallelism(30);
php.add(fl11);
php.add(fl21);
php.add(fl22);
php.connect(sp11, fl11);
php.connect(sp21, fl21);
php.connect(sp21, fl22);
POLocalRearrange lr1 = GenPhyOp.topLocalRearrangeOp();
lr1.setRequestedParallelism(40);
POLocalRearrange lr21 = GenPhyOp.topLocalRearrangeOp();
lr21.setRequestedParallelism(15);
POLocalRearrange lr22 = GenPhyOp.topLocalRearrangeOp();
lr22.setRequestedParallelism(35);
php.add(lr1);
php.add(lr21);
php.add(lr22);
php.connect(fl11, lr1);
php.connect(fl21, lr21);
php.connect(fl22, lr22);
POGlobalRearrange gr = GenPhyOp.topGlobalRearrangeOp();
php.addAsLeaf(gr);
POPackage pk = GenPhyOp.topPackageOp();
pk.setRequestedParallelism(25);
php.addAsLeaf(pk);
POSplit sp2 = GenPhyOp.topSplitOp();
php.addAsLeaf(sp2);
POFilter fl3 = GenPhyOp.topFilterOp();
fl3.setRequestedParallelism(100);
POFilter fl4 = GenPhyOp.topFilterOp();
fl4.setRequestedParallelism(80);
php.add(fl3);
php.add(fl4);
php.connect(sp2, fl3);
php.connect(sp2, fl4);
POUnion un = GenPhyOp.topUnionOp();
php.addAsLeaf(un);
POStore st = GenPhyOp.topStoreOp();
php.addAsLeaf(st);
run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC14.gld");
}
@Test
public void testRun1() throws Exception {
PhysicalPlan php = new PhysicalPlan();
PhysicalPlan part1 = new PhysicalPlan();
POLoad lC = GenPhyOp.topLoadOp();
POFilter fC = GenPhyOp.topFilterOp();
fC.setRequestedParallelism(20);
POLocalRearrange lrC = GenPhyOp.topLocalRearrangeOp();
lrC.setRequestedParallelism(10);
POGlobalRearrange grC = GenPhyOp.topGlobalRearrangeOp();
POPackage pkC = GenPhyOp.topPackageOp();
part1.add(lC);
part1.add(fC);
part1.connect(lC, fC);
part1.add(lrC);
part1.connect(fC, lrC);
part1.add(grC);
part1.connect(lrC, grC);
part1.add(pkC);
part1.connect(grC, pkC);
POPackage pkD = GenPhyOp.topPackageOp();
pkD.setRequestedParallelism(20);
POLocalRearrange lrD = GenPhyOp.topLocalRearrangeOp();
lrD.setRequestedParallelism(30);
POGlobalRearrange grD = GenPhyOp.topGlobalRearrangeOp();
POLoad lD = GenPhyOp.topLoadOp();
part1.add(lD);
part1.add(lrD);
part1.connect(lD, lrD);
part1.add(grD);
part1.connect(lrD, grD);
part1.add(pkD);
part1.connect(grD, pkD);
POPackage pkCD = GenPhyOp.topPackageOp();
POLocalRearrange lrCD1 = GenPhyOp.topLocalRearrangeOp();
POLocalRearrange lrCD2 = GenPhyOp.topLocalRearrangeOp();
POGlobalRearrange grCD = GenPhyOp.topGlobalRearrangeOp();
part1.add(lrCD1);
part1.add(lrCD2);
part1.connect(pkC, lrCD1);
part1.connect(pkD, lrCD2);
part1.add(grCD);
part1.connect(lrCD1, grCD);
part1.connect(lrCD2, grCD);
part1.add(pkCD);
part1.connect(grCD, pkCD);
POLoad lA = GenPhyOp.topLoadOp();
POLoad lB = GenPhyOp.topLoadOp();
// POLoad lC = lA;
POFilter fA = GenPhyOp.topFilterOp();
POLocalRearrange lrA = GenPhyOp.topLocalRearrangeOp();
POLocalRearrange lrB = GenPhyOp.topLocalRearrangeOp();
POGlobalRearrange grAB = GenPhyOp.topGlobalRearrangeOp();
POPackage pkAB = GenPhyOp.topPackageOp();
POFilter fAB = GenPhyOp.topFilterOp();
POUnion unABC = GenPhyOp.topUnionOp();
php.add(lA);
php.add(lB);
php.add(fA);
php.connect(lA, fA);
php.add(lrA);
php.add(lrB);
php.connect(fA, lrA);
php.connect(lB, lrB);
php.add(grAB);
php.connect(lrA, grAB);
php.connect(lrB, grAB);
php.add(pkAB);
php.connect(grAB, pkAB);
php.add(fAB);
php.connect(pkAB, fAB);
php.merge(part1);
List<PhysicalOperator> leaves = new ArrayList<PhysicalOperator>();
for (PhysicalOperator phyOp : php.getLeaves()) {
leaves.add(phyOp);
}
php.add(unABC);
for (PhysicalOperator physicalOperator : leaves) {
php.connect(physicalOperator, unABC);
}
POStore st = GenPhyOp.topStoreOp();
php.add(st);
php.connect(unABC, st);
run(php, "test/org/apache/pig/test/data/GoldenFiles/MRC10.gld");
}
/**
* Algebraic functions and distinct in nested plan of a foreach are partially computed in the map
* and combine phase. A new foreach statement with initial and intermediate forms of algebraic
* functions are added to map and combine plans respectively.
*
* <p>If bag portion of group-by result is projected or a non algebraic expression/udf has bag as
* input, combiner will not be used. This is because the use of combiner in such case is likely to
* degrade performance as there will not be much reduction in data size in combine stage to offset
* the cost of the additional number of times (de)serialization is done.
*
* <p>Major areas for enhancement: 1. use of combiner in cogroup 2. queries with order-by, limit
* or sort in a nested foreach after group-by 3. case where group-by is followed by filter that
* has algebraic expression
*/
public static void addCombiner(
PhysicalPlan mapPlan,
PhysicalPlan reducePlan,
PhysicalPlan combinePlan,
CompilationMessageCollector messageCollector,
boolean doMapAgg)
throws VisitorException {
// part one - check if this MR job represents a group-by + foreach. Find
// the POLocalRearrange in the map. I'll need it later.
List<PhysicalOperator> mapLeaves = mapPlan.getLeaves();
if (mapLeaves == null || mapLeaves.size() != 1) {
messageCollector.collect(
"Expected map to have single leaf", MessageType.Warning, PigWarning.MULTI_LEAF_MAP);
return;
}
PhysicalOperator mapLeaf = mapLeaves.get(0);
if (!(mapLeaf instanceof POLocalRearrange)) {
return;
}
POLocalRearrange rearrange = (POLocalRearrange) mapLeaf;
List<PhysicalOperator> reduceRoots = reducePlan.getRoots();
if (reduceRoots.size() != 1) {
messageCollector.collect(
"Expected reduce to have single root", MessageType.Warning, PigWarning.MULTI_ROOT_REDUCE);
return;
}
// I expect that the first root should always be a POPackage. If not, I
// don't know what's going on, so I'm out of here.
PhysicalOperator root = reduceRoots.get(0);
if (!(root instanceof POPackage)) {
messageCollector.collect(
"Expected reduce root to be a POPackage",
MessageType.Warning,
PigWarning.NON_PACKAGE_REDUCE_PLAN_ROOT);
return;
}
POPackage pack = (POPackage) root;
List<PhysicalOperator> packSuccessors = reducePlan.getSuccessors(root);
if (packSuccessors == null || packSuccessors.size() != 1) {
return;
}
PhysicalOperator successor = packSuccessors.get(0);
if (successor instanceof POLimit) {
// POLimit is acceptable, as long has it has a single foreach as
// successor
List<PhysicalOperator> limitSucs = reducePlan.getSuccessors(successor);
if (limitSucs != null && limitSucs.size() == 1 && limitSucs.get(0) instanceof POForEach) {
// the code below will now further examine the foreach
successor = limitSucs.get(0);
}
}
if (successor instanceof POForEach) {
POForEach foreach = (POForEach) successor;
List<PhysicalPlan> feInners = foreach.getInputPlans();
// find algebraic operators and also check if the foreach statement
// is suitable for combiner use
List<Pair<PhysicalOperator, PhysicalPlan>> algebraicOps = findAlgebraicOps(feInners);
if (algebraicOps == null || algebraicOps.size() == 0) {
// the plan is not combinable or there is nothing to combine
// we're done
return;
}
if (combinePlan != null && combinePlan.getRoots().size() != 0) {
messageCollector.collect(
"Wasn't expecting to find anything already " + "in the combiner!",
MessageType.Warning,
PigWarning.NON_EMPTY_COMBINE_PLAN);
return;
}
LOG.info("Choosing to move algebraic foreach to combiner");
try {
// replace PODistinct->Project[*] with distinct udf (which is Algebraic)
for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
if (!(op2plan.first instanceof PODistinct)) {
continue;
}
DistinctPatcher distinctPatcher = new DistinctPatcher(op2plan.second);
distinctPatcher.visit();
if (distinctPatcher.getDistinct() == null) {
int errCode = 2073;
String msg =
"Problem with replacing distinct operator with distinct built-in function.";
throw new PlanException(msg, errCode, PigException.BUG);
}
op2plan.first = distinctPatcher.getDistinct();
}
// create new map foreach
POForEach mfe = createForEachWithGrpProj(foreach, rearrange.getKeyType());
Map<PhysicalOperator, Integer> op2newpos = Maps.newHashMap();
Integer pos = 1;
// create plan for each algebraic udf and add as inner plan in map-foreach
for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
PhysicalPlan udfPlan = createPlanWithPredecessors(op2plan.first, op2plan.second);
mfe.addInputPlan(udfPlan, false);
op2newpos.put(op2plan.first, pos++);
}
changeFunc(mfe, POUserFunc.INITIAL);
// since we will only be creating SingleTupleBag as input to
// the map foreach, we should flag the POProjects in the map
// foreach inner plans to also use SingleTupleBag
for (PhysicalPlan mpl : mfe.getInputPlans()) {
try {
new fixMapProjects(mpl).visit();
} catch (VisitorException e) {
int errCode = 2089;
String msg = "Unable to flag project operator to use single tuple bag.";
throw new PlanException(msg, errCode, PigException.BUG, e);
}
}
// create new combine foreach
POForEach cfe = createForEachWithGrpProj(foreach, rearrange.getKeyType());
// add algebraic functions with appropriate projection
addAlgebraicFuncToCombineFE(cfe, op2newpos);
changeFunc(cfe, POUserFunc.INTERMEDIATE);
// fix projection and function time for algebraic functions in reduce foreach
for (Pair<PhysicalOperator, PhysicalPlan> op2plan : algebraicOps) {
setProjectInput(op2plan.first, op2plan.second, op2newpos.get(op2plan.first));
byte resultType = op2plan.first.getResultType();
((POUserFunc) op2plan.first).setAlgebraicFunction(POUserFunc.FINAL);
op2plan.first.setResultType(resultType);
}
// we have modified the foreach inner plans - so set them again
// for the foreach so that foreach can do any re-initialization
// around them.
// FIXME - this is a necessary evil right now because the leaves
// are explicitly stored in the POForeach as a list rather than
// computed each time at run time from the plans for
// optimization. Do we want to have the Foreach compute the
// leaves each time and have Java optimize it (will Java
// optimize?)?
mfe.setInputPlans(mfe.getInputPlans());
cfe.setInputPlans(cfe.getInputPlans());
foreach.setInputPlans(foreach.getInputPlans());
// tell POCombinerPackage which fields need projected and which
// placed in bags. First field is simple project rest need to go
// into bags
int numFields = algebraicOps.size() + 1; // algebraic funcs + group key
boolean[] bags = new boolean[numFields];
bags[0] = false;
for (int i = 1; i < numFields; i++) {
bags[i] = true;
}
// Use the POCombiner package in the combine plan
// as it needs to act differently than the regular
// package operator.
CombinerPackager pkgr = new CombinerPackager(pack.getPkgr(), bags);
POPackage combinePack = pack.clone();
combinePack.setPkgr(pkgr);
combinePack.setParentPlan(null);
combinePlan.add(combinePack);
combinePlan.add(cfe);
combinePlan.connect(combinePack, cfe);
// No need to connect projections in cfe to cp, because
// PigCombiner directly attaches output from package to
// root of remaining plan.
POLocalRearrange mlr = getNewRearrange(rearrange);
POPartialAgg mapAgg = null;
if (doMapAgg) {
mapAgg = createPartialAgg(cfe);
}
// A specialized local rearrange operator will replace
// the normal local rearrange in the map plan. This behaves
// like the regular local rearrange in the getNext()
// as far as getting its input and constructing the
// "key" out of the input. It then returns a tuple with
// two fields - the key in the first position and the
// "value" inside a bag in the second position. This output
// format resembles the format out of a Package. This output
// will feed to the map foreach which expects this format.
// If the key field isn't in the project of the combiner or map foreach,
// it is added to the end (This is required so that we can
// set up the inner plan of the new Local Rearrange leaf in the map
// and combine plan to contain just the project of the key).
patchUpMap(mapPlan, getPreCombinerLR(rearrange), mfe, mapAgg, mlr);
POLocalRearrange clr = getNewRearrange(rearrange);
clr.setParentPlan(null);
combinePlan.add(clr);
combinePlan.connect(cfe, clr);
// Change the package operator in the reduce plan to
// be the POCombiner package, as it needs to act
// differently than the regular package operator.
pack.setPkgr(pkgr.clone());
} catch (Exception e) {
int errCode = 2018;
String msg = "Internal error. Unable to introduce the combiner for optimization.";
throw new OptimizerException(msg, errCode, PigException.BUG, e);
}
}
}
@Override
public void visitLocalRearrange(POLocalRearrange lr) throws VisitorException {
this.mro.mapKeyType = lr.getKeyType();
foundKeyType = true;
}