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C++ Join::updatePotential方法代码示例

本文整理汇总了C++中Join::updatePotential方法的典型用法代码示例。如果您正苦于以下问题:C++ Join::updatePotential方法的具体用法?C++ Join::updatePotential怎么用?C++ Join::updatePotential使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在Join的用法示例。



在下文中一共展示了Join::updatePotential方法的1个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于我们的系统推荐出更棒的C++代码示例。

示例1: leftLinearize

// ------------------------------------------------------------------------
// Create a left linear subtree of joins from this MultiJoin
// ------------------------------------------------------------------------
Join* MultiJoin::leftLinearize(NABoolean fixJoinOrder, NABoolean createPriviledgedJoins) const
{
  // At this point assert that the subsets has no group by member.
  // If we want to allow GBs in this method in the future we should
  // remember to use computeJBBSubset() instead of the faster
  // jbbcsToJBBSubset() used currently in this method..
  CMPASSERT ( (jbbSubset_.getGB() == NULL_CA_ID));

  const CANodeIdSet & jbbcs = jbbSubset_.getJBBCs();
  // pick some child to make right child of join
  CANodeId jbbcRight(jbbcs.getFirst());

  CANodeIdSet right(jbbcRight);
  CANodeIdSet left(jbbcs);
  left -= jbbcRight;

  NABoolean nonExpander = (left.jbbcsToJBBSubset()->
    isGuaranteedNonExpandingJoin((*jbbcRight.getNodeAnalysis()->getJBBC())));

  Join* result = splitSubset(*(left.jbbcsToJBBSubset()),
                             *(right.jbbcsToJBBSubset()));

  if (fixJoinOrder)
  {
    // disallow left shift rule on the join
    result->contextInsensRules() += JoinLeftShiftRuleNumber;
    // disallow join commutativity on the join
    result->contextInsensRules() += JoinCommutativityRuleNumber;
  }

  if (createPriviledgedJoins)
  {
    result->setJoinFromPTRule();

    if ( CmpCommon::getDefault(COMP_BOOL_120) == DF_OFF)
    {
      result->updatePotential(-2);
    }
  }

  // If left subset is a multiJoin, then linearize it too.
  if (left.entries() > 1)
  {
    // left child must be multiJoin at this point. May be add assert.
    MultiJoin* leftChild = (MultiJoin*)(result->child(0).getPtr());
    result->child(0) = leftChild->leftLinearize(fixJoinOrder,createPriviledgedJoins);
  }

  return result;
} // MultiJoin::leftLinearize()
开发者ID:lanbb,项目名称:incubator-trafodion,代码行数:53,代码来源:MultiJoin.cpp



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