/**
* 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.tajo.engine.planner.physical;
import com.google.common.base.Preconditions;
import org.apache.tajo.SessionVars;
import org.apache.tajo.catalog.SortSpec;
import org.apache.tajo.plan.logical.JoinNode;
import org.apache.tajo.storage.NullTuple;
import org.apache.tajo.storage.Tuple;
import org.apache.tajo.storage.TupleComparator;
import org.apache.tajo.storage.VTuple;
import org.apache.tajo.worker.TaskAttemptContext;
import java.io.IOException;
public class MergeFullOuterJoinExec extends CommonJoinExec {
// temporal tuples and states for nested loop join
private Tuple leftTuple = null;
private Tuple rightTuple = null;
private Tuple leftNext = null;
private Tuple prevLeftTuple = null;
private Tuple prevRightTuple = null;
private Tuple preservedTuple = null;
private TupleList leftTupleSlots;
private TupleList rightTupleSlots;
private JoinTupleComparator joincomparator = null;
private TupleComparator[] tupleComparator = null;
private boolean end = false;
private int rightNumCols;
private int leftNumCols;
private int posRightTupleSlots = -1;
private int posLeftTupleSlots = -1;
boolean endInPopulationStage = false;
private boolean initRightDone = false;
private final Tuple leftNullTuple;
private final Tuple rightNullTuple;
public MergeFullOuterJoinExec(TaskAttemptContext context, JoinNode plan, PhysicalExec leftChild,
PhysicalExec rightChild, SortSpec[] leftSortKey, SortSpec[] rightSortKey) {
super(context, plan, leftChild, rightChild);
Preconditions.checkArgument(plan.hasJoinQual(), "Sort-merge join is only used for the equi-join, " +
"but there is no join condition");
final int INITIAL_TUPLE_SLOT = context.getQueryContext().getInt(SessionVars.JOIN_HASH_TABLE_SIZE);
this.leftTupleSlots = new TupleList(INITIAL_TUPLE_SLOT);
this.rightTupleSlots = new TupleList(INITIAL_TUPLE_SLOT);
SortSpec[][] sortSpecs = new SortSpec[2][];
sortSpecs[0] = leftSortKey;
sortSpecs[1] = rightSortKey;
this.joincomparator = new JoinTupleComparator(leftChild.getSchema(),
rightChild.getSchema(), sortSpecs);
this.tupleComparator = PhysicalPlanUtil.getComparatorsFromJoinQual(
plan.getJoinQual(), leftChild.getSchema(), rightChild.getSchema());
leftNumCols = leftChild.getSchema().size();
rightNumCols = rightChild.getSchema().size();
prevLeftTuple = new VTuple(leftChild.getSchema().size());
prevRightTuple = new VTuple(rightChild.getSchema().size());
leftNullTuple = NullTuple.create(leftNumCols);
rightNullTuple = NullTuple.create(rightNumCols);
}
public Tuple next() throws IOException {
Tuple outTuple;
while (!context.isStopped()) {
if (preservedTuple != null) {
outTuple = preservedTuple;
preservedTuple = null;
return outTuple;
}
boolean newRound = false;
if((posRightTupleSlots == -1) && (posLeftTupleSlots == -1)) {
newRound = true;
}
if ((posRightTupleSlots == rightTupleSlots.size()) && (posLeftTupleSlots == leftTupleSlots.size())) {
newRound = true;
}
if(newRound){
if (end) {
////////////////////////////////////////////////////////////////////////
// FINALIZING STAGE
////////////////////////////////////////////////////////////////////////
// the finalizing stage, where remaining tuples on the right are
// transformed into left-padded results while tuples on the left
// are transformed into right-padded results
// before exit, a left-padded tuple should be built for all remaining
// right side and a right-padded tuple should be built for all remaining
// left side
if (!initRightDone) {
// maybe the left operand was empty => the right one didn't have the chance to initialize
rightTuple = rightChild.next();
initRightDone = true;
}
if((leftTuple == null) && (rightTuple == null)) {
return null;
}
if((leftTuple == null) && (rightTuple != null)){
// output a tuple with the nulls padded leftTuple
frameTuple.set(leftNullTuple, rightTuple);
outTuple = projector.eval(frameTuple);
// we simulate we found a match, which is exactly the null padded one
rightTuple = rightChild.next();
return outTuple;
}
if((leftTuple != null) && (rightTuple == null)){
// output a tuple with the nulls padded leftTuple
frameTuple.set(leftTuple, rightNullTuple);
outTuple = projector.eval(frameTuple);
// we simulate we found a match, which is exactly the null padded one
leftTuple = leftChild.next();
return outTuple;
}
} // if end
////////////////////////////////////////////////////////////////////////
// INITIALIZING STAGE
////////////////////////////////////////////////////////////////////////
// initializing stage, reading the first tuple on each side
if (leftTuple == null) {
leftTuple = leftChild.next();
if( leftTuple == null){
end = true;
continue;
}
}
if (rightTuple == null) {
rightTuple = rightChild.next();
initRightDone = true;
if (rightTuple == null) {
end = true;
continue;
}
}
// reset tuple slots for a new round
leftTupleSlots.clear();
rightTupleSlots.clear();
posRightTupleSlots = -1;
posLeftTupleSlots = -1;
////////////////////////////////////////////////////////////////////////
// Comparison and Move Forward Stage
////////////////////////////////////////////////////////////////////////
// advance alternatively on each side until a match is found
int cmp;
if (!end && ((cmp = joincomparator.compare(leftTuple, rightTuple)) != 0)) {
if (cmp > 0) {
//before getting a new tuple from the right, a leftnullpadded tuple should be built
//output a tuple with the nulls padded leftTuple
Tuple nullPaddedTuple = leftNullTuple;
frameTuple.set(nullPaddedTuple, rightTuple);
outTuple = projector.eval(frameTuple);
// BEFORE RETURN, MOVE FORWARD
rightTuple = rightChild.next();
if(rightTuple == null) {
end = true;
}
return outTuple;
} else if (cmp < 0) {
// before getting a new tuple from the left, a rightnullpadded tuple should be built
// output a tuple with the nulls padded rightTuple
Tuple nullPaddedTuple = rightNullTuple;
frameTuple.set(leftTuple, nullPaddedTuple);
outTuple = projector.eval(frameTuple);
// we simulate we found a match, which is exactly the null padded one
// BEFORE RETURN, MOVE FORWARD
leftTuple = leftChild.next();
if(leftTuple == null) {
end = true;
}
return outTuple;
}
}
// Check null values
Tuple leftKey = leftKeyExtractor.project(leftTuple);
boolean containNull = false;
for (int i = 0; i < leftKey.size(); i++) {
if (leftKey.isBlankOrNull(i)) {
containNull = true;
break;
}
}
if (containNull) {
frameTuple.set(leftTuple, rightNullTuple);
outTuple = projector.eval(frameTuple);
frameTuple.set(leftNullTuple, rightTuple);
preservedTuple = new VTuple(projector.eval(frameTuple));
leftTuple = leftChild.next();
rightTuple = rightChild.next();
if (leftTuple == null || rightTuple == null) {
end = true;
}
return outTuple;
}
////////////////////////////////////////////////////////////////////////
// SLOTS POPULATION STAGE
////////////////////////////////////////////////////////////////////////
// once a match is found, retain all tuples with this key in tuple slots
// on each side
if(!end) {
endInPopulationStage = false;
boolean endLeft = false;
boolean endRight = false;
prevLeftTuple.put(leftTuple.getValues());
do {
leftTupleSlots.add(leftTuple);
leftTuple = leftChild.next();
if(leftTuple == null) {
endLeft = true;
}
} while ((!endLeft) && (tupleComparator[0].compare(prevLeftTuple, leftTuple) == 0));
posLeftTupleSlots = 0;
prevRightTuple.put(rightTuple.getValues());
do {
rightTupleSlots.add(rightTuple);
rightTuple = rightChild.next();
if(rightTuple == null) {
endRight = true;
}
} while ((!endRight) && (tupleComparator[1].compare(prevRightTuple, rightTuple) == 0) );
posRightTupleSlots = 0;
if ((endLeft) || (endRight)) {
end = true;
endInPopulationStage = true;
}
} // if end false
} // if newRound
////////////////////////////////////////////////////////////////////////
// RESULTS STAGE
////////////////////////////////////////////////////////////////////////
// now output result matching tuples from the slots
// if either we haven't reached end on neither side, or we did reach end
// on one(or both) sides but that happened in the slots population step
// (i.e. refers to next round)
if(!end || (end && endInPopulationStage)){
if(posLeftTupleSlots == 0){
leftNext = leftTupleSlots.get(posLeftTupleSlots);
posLeftTupleSlots++;
}
if(posRightTupleSlots <= (rightTupleSlots.size() -1)) {
Tuple aTuple = rightTupleSlots.get(posRightTupleSlots);
posRightTupleSlots++;
frameTuple.set(leftNext, aTuple);
joinQual.eval(frameTuple);
return projector.eval(frameTuple);
} else {
// right (inner) slots reached end and should be rewind if there are still tuples in the outer slots
if(posLeftTupleSlots <= (leftTupleSlots.size()-1)) {
//rewind the right slots position
posRightTupleSlots = 0;
Tuple aTuple = rightTupleSlots.get(posRightTupleSlots);
posRightTupleSlots = posRightTupleSlots + 1;
leftNext = leftTupleSlots.get(posLeftTupleSlots);
posLeftTupleSlots = posLeftTupleSlots + 1;
frameTuple.set(leftNext, aTuple);
joinQual.eval(frameTuple);
return projector.eval(frameTuple);
}
}
} // the second if end false
} // for
return null;
}
@Override
public void rescan() throws IOException {
super.rescan();
leftTupleSlots.clear();
rightTupleSlots.clear();
posRightTupleSlots = -1;
posLeftTupleSlots = -1;
}
@Override
public void close() throws IOException {
super.close();
leftTupleSlots.clear();
rightTupleSlots.clear();
leftTupleSlots = null;
rightTupleSlots = null;
}
}