/**
* Pipeline joins
*
* @return
*/
public Operator pipeline() {
EqualJoin firstJoin = joinList.get(0);
TimeCalc.begin(firstJoin.toString());
OperatorHashJoin hashJoin = decideWhichToCreate(firstJoin, operMap);
TimeCalc.end(firstJoin.toString() + " Finish create the first hash join.");
joinedHistory.add(firstJoin.getLeftTableName());
joinedHistory.add(firstJoin.getRightTableName());
for (int i = 1; i < joinList.size(); i++) {
EqualJoin ej = joinList.get(i);
Operator leftOper = operMap.get(ej.getLeftTableName());
Operator rightOper = operMap.get(ej.getRightTableName());
Operator neverJoinedOper;
if (joinedHistory.contains(ej.getLeftTableName())) neverJoinedOper = rightOper;
else neverJoinedOper = leftOper;
TimeCalc.begin(ej.toString());
hashJoin = decideWhichToCreate(ej, hashJoin, neverJoinedOper);
TimeCalc.end(ej.toString() + " Finish pipeline one hash join " + ej);
joinedHistory.add(ej.getLeftTableName());
joinedHistory.add(ej.getRightTableName());
}
return hashJoin;
}
