C++ Join::setDerivedFromRoutineJoin方法代码示例

//.........这里部分代码省略.........
    {
      if(rightChildParentJoin->derivedFromRoutineJoin())
        derivedFromRoutineJoin = TRUE;

      if(rightChildParentJoin->isSemiJoin())
        result = new (outHeap) Join(child0, child1, REL_SEMIJOIN, NULL);

      if(rightChildParentJoin->isAntiSemiJoin())
        result = new (outHeap) Join(child0, child1, REL_ANTI_SEMIJOIN, NULL);

      if(rightChildParentJoin->isLeftJoin())
      {

        // left joins can have filter preds, i.e. predicates that
        // are applied as filters after applying the join predicate.
        // We need to set them here.
        result = new (outHeap) Join(child0, child1, REL_LEFT_JOIN, NULL);
        result->setSelectionPredicates(rightChild->getLeftJoinFilterPreds());
      }
      
      if(rightChildParentJoin->isRoutineJoin())
      {
        derivedFromRoutineJoin = TRUE;
        result = new (outHeap) Join(child0, child1, REL_ROUTINE_JOIN, NULL);
        ValueIdSet routineJoinFilterPreds = rightChild->getRoutineJoinFilterPreds();
        ValueIdSet predsToAddToRoutineJoin;
          
        // add covered filter preds
        for (ValueId filterPred= routineJoinFilterPreds.init();
             routineJoinFilterPreds.next(filterPred);
             routineJoinFilterPreds.advance(filterPred) )
        {
          if(jbbSubset_.coversExpr(filterPred))
            predsToAddToRoutineJoin += filterPred;
        } 
 
        result->setSelectionPredicates(predsToAddToRoutineJoin);
      }

      if(result)
      {
        // set the join predicate for special joins, note predicates
        // for regular InnerNonSemi joins are set as selection predicates
        // in the join relexpr.
        result->setJoinPred(rightChild->getPredsWithPredecessors());

        result->nullInstantiatedOutput().insert(rightChild->
                                                  nullInstantiatedOutput());
      }
    }
  }

  // The join to be created is a regular InnerNonSemi join
  if (!result)
    result = new (outHeap) Join(child0, child1, REL_JOIN, NULL);

  // Make sure we carry the derivedFromRoutineJoin flag with us 
  if (derivedFromRoutineJoin)
    result->setDerivedFromRoutineJoin();

  // Share my groupAttr with result
  result->setGroupAttr(getGroupAttr());

  // get inner join predicates
  ValueIdSet selPreds = rightSet.joinPredsWithOther(leftSet);

  // get left join filter preds if any
  selPreds += result->getSelectionPredicates();

  result->setSelectionPredicates(selPreds);

  result->findEquiJoinPredicates();

  // May be I could save a little if i pushdown only to the child(ren)
  // that are not already JBBCs, i.e. multijoins
  result->pushdownCoveredExpr
    (result->getGroupAttr()->getCharacteristicOutputs(),
     result->getGroupAttr()->getCharacteristicInputs(),
     result->selectionPred());

  // We used CutOp as children, to avoid pushing predicates to JBBCs.
  // Now put the actual expression back in case the child is a JBBCs
  if(leftSet.getJBBCs().entries() ==  1)
    result->setChild(0, getJBBCRelExpr(leftSet.getJBBCs().getFirst()));

  // We used CutOp as children, to avoid pushing predicates to JBBCs.
  // Now put the actual expression back in case the child is a JBBCs
  if(rightSet.getJBBCs().entries() ==  1)
    result->setChild(1, getJBBCRelExpr(rightSet.getJBBCs().getFirst()));

  // Temp fixup. We need to take the selectionPred out of MultiJoin
  // for now to prevent that pushed expr from being there. selectionPred
  // is not being used now in MultiJoin xxx.
  if (leftSet.getJBBCs().entries() > 1)
    result->child(0)->selectionPred().clear();
  if (rightSet.getJBBCs().entries() > 1)
    result->child(1)->selectionPred().clear();

  return result;
}