@Override
public Tuple next() throws IOException {
Tuple aTuple;
Tuple outTuple = new VTuple(outColumnNum);
if (isClosed) {
return null;
}
if (cachedData.size() == 0) {
rescan();
}
if (!scanNode.hasQual()) {
if (currentRow < cachedData.size()) {
aTuple = cachedData.get(currentRow++);
projector.eval(aTuple, outTuple);
outTuple.setOffset(aTuple.getOffset());
return outTuple;
}
return null;
} else {
while (currentRow < cachedData.size()) {
aTuple = cachedData.get(currentRow++);
if (qual.eval(aTuple).isTrue()) {
projector.eval(aTuple, outTuple);
return outTuple;
}
}
return null;
}
}
public MergeJoinExec(
TaskAttemptContext context,
JoinNode plan,
PhysicalExec outer,
PhysicalExec inner,
SortSpec[] outerSortKey,
SortSpec[] innerSortKey) {
super(context, plan.getInSchema(), plan.getOutSchema(), outer, inner);
Preconditions.checkArgument(
plan.hasJoinQual(),
"Sort-merge join is only used for the equi-join, " + "but there is no join condition");
this.joinNode = plan;
this.joinQual = plan.getJoinQual();
this.qualCtx = this.joinQual.newContext();
this.outerTupleSlots = new ArrayList<Tuple>(INITIAL_TUPLE_SLOT);
this.innerTupleSlots = new ArrayList<Tuple>(INITIAL_TUPLE_SLOT);
SortSpec[][] sortSpecs = new SortSpec[2][];
sortSpecs[0] = outerSortKey;
sortSpecs[1] = innerSortKey;
this.joincomparator = new JoinTupleComparator(outer.getSchema(), inner.getSchema(), sortSpecs);
this.tupleComparator =
PlannerUtil.getComparatorsFromJoinQual(
plan.getJoinQual(), outer.getSchema(), inner.getSchema());
this.outerIterator = outerTupleSlots.iterator();
this.innerIterator = innerTupleSlots.iterator();
// for projection
this.projector = new Projector(inSchema, outSchema, plan.getTargets());
this.evalContexts = projector.renew();
// for join
frameTuple = new FrameTuple();
outTuple = new VTuple(outSchema.getColumnNum());
}
public Tuple next() throws IOException {
Tuple previous;
for (; ; ) {
if (!outerIterator.hasNext() && !innerIterator.hasNext()) {
if (end) {
return null;
}
if (outerTuple == null) {
outerTuple = leftChild.next();
}
if (innerTuple == null) {
innerTuple = rightChild.next();
}
outerTupleSlots.clear();
innerTupleSlots.clear();
int cmp;
while ((cmp = joincomparator.compare(outerTuple, innerTuple)) != 0) {
if (cmp > 0) {
innerTuple = rightChild.next();
} else if (cmp < 0) {
outerTuple = leftChild.next();
}
if (innerTuple == null || outerTuple == null) {
return null;
}
}
try {
previous = outerTuple.clone();
do {
outerTupleSlots.add(outerTuple.clone());
outerTuple = leftChild.next();
if (outerTuple == null) {
end = true;
break;
}
} while (tupleComparator[0].compare(previous, outerTuple) == 0);
outerIterator = outerTupleSlots.iterator();
outerNext = outerIterator.next();
previous = innerTuple.clone();
do {
innerTupleSlots.add(innerTuple.clone());
innerTuple = rightChild.next();
if (innerTuple == null) {
end = true;
break;
}
} while (tupleComparator[1].compare(previous, innerTuple) == 0);
innerIterator = innerTupleSlots.iterator();
} catch (CloneNotSupportedException e) {
}
}
if (!innerIterator.hasNext()) {
outerNext = outerIterator.next();
innerIterator = innerTupleSlots.iterator();
}
frameTuple.set(outerNext, innerIterator.next());
joinQual.eval(qualCtx, inSchema, frameTuple);
if (joinQual.terminate(qualCtx).asBool()) {
projector.eval(evalContexts, frameTuple);
projector.terminate(evalContexts, outTuple);
return outTuple;
}
}
}
