C++ CANodeIdSet::subtractSet方法代码示例

Join * AppliedStatMan::formJoinExprWithCANodeSets(
					const CANodeIdSet & leftNodeSet,
					const CANodeIdSet & rightNodeSet,
					EstLogPropSharedPtr& inLP,
					const ValueIdSet * joinPreds,
					const NABoolean cacheable)
{
  EstLogPropSharedPtr leftEstLogProp = NULL;
  EstLogPropSharedPtr rightEstLogProp = NULL;

  CANodeIdSet * inputNodeSet = NULL;
  if (inLP->isCacheable())
  {
    inputNodeSet = inLP->getNodeSet();

    // if inLP are cacheable these should have a nodeSet attached
    // if it is not for some reason, assert in debug mode. In release
    // mode do not look for properties in ASM cache, instead get them
    // from group attr cache.
    if (inputNodeSet == NULL)
    {
      CCMPASSERT(inputNodeSet != NULL);
      inLP->setCacheableFlag(FALSE);
    }
  }

  CANodeIdSet commonNodeSet = leftNodeSet;
  commonNodeSet.intersectSet(rightNodeSet);

  // remove CANodeIds which are common to both left and the right children
  // from the child, whose estLogProps are not cached. If the estLogProps
  // of both children are not cached, then remove it from the child which
  // has a larger CANodeIdSet associated with it.

  CANodeIdSet tempLeftNodeSet = leftNodeSet;
  CANodeIdSet tempRightNodeSet = rightNodeSet;

  if (commonNodeSet.entries() > 0)
  {
    if (lookup(leftNodeSet))
      tempRightNodeSet.subtractSet(commonNodeSet);
    else
      if (lookup(rightNodeSet))
	tempLeftNodeSet.subtractSet(commonNodeSet);
      else
	if (leftNodeSet.entries() > rightNodeSet.entries())
	  tempLeftNodeSet.subtractSet(commonNodeSet);
	else
	  tempRightNodeSet.subtractSet(commonNodeSet);
  }

  // get the estLogProps for the left and the right child.
  // If these are not in the cache, then synthesize them incrementally
  // starting from the left most JBBC in the JBBSubset

  if (inputNodeSet)
  {
    // leftEstLogProp cached?

    CANodeIdSet combinedNodeSetWithInput = tempLeftNodeSet;
    combinedNodeSetWithInput.insert(*inputNodeSet);

    leftEstLogProp = getCachedStatistics(&combinedNodeSetWithInput);

    combinedNodeSetWithInput = tempRightNodeSet;
    combinedNodeSetWithInput.insert(*inputNodeSet);

    rightEstLogProp = getCachedStatistics(&combinedNodeSetWithInput);
  }

  if (leftEstLogProp == NULL)
      leftEstLogProp = synthesizeLogProp(&tempLeftNodeSet, inLP);

  // if the estimate logical properties have been computed for non-cacheable
  // inLP, then these would not contain nodeSet. But we do need the nodeSet
  // to compute potential output values. Hence we shall add this now

  if (!leftEstLogProp->getNodeSet())
  {
    CANodeIdSet * copyLeftNodeSet = new (STMTHEAP) CANodeIdSet (tempLeftNodeSet);
    leftEstLogProp->setNodeSet(copyLeftNodeSet);
  }

  if (rightEstLogProp == NULL)
      rightEstLogProp = synthesizeLogProp(&tempRightNodeSet, inLP);

  if (!rightEstLogProp->getNodeSet())
  {
    CANodeIdSet * copyRightNodeSet = new (STMTHEAP) CANodeIdSet (tempRightNodeSet);
    rightEstLogProp->setNodeSet(copyRightNodeSet);
  }

  // Now form the join expressions with these EstLogProp,
  // inLP and the joinPred will be same as those for which the
  // estLogProp are to be synthesized. Cacheable flag would depend
  // on whether left, right and the outer child are caheable, or
  // if the join is on all columns or not

  // Since the join expression consists of the left and the right
  // JBBSubsets, the JBBSubset for this Join expression would be
//.........这里部分代码省略.........