C++ Scan::getGroupAttr方法代码示例

// AppliedStatMan::setupASMCacheForJBB method will be called from
// Query::Analyze after connectivity analysis has been done and
// empty logical properties have been set.
void AppliedStatMan::setupASMCacheForJBB(JBB & jbb)
{
  EstLogPropSharedPtr myEstLogProp;

  // get all JBBCs of JBB
  const CANodeIdSet jbbcNodeIdSet = jbb.getMainJBBSubset().getJBBCs();
  CANodeId jbbcId;

  // for all jbbcs
  for (jbbcId = jbbcNodeIdSet.init();
	  jbbcNodeIdSet.next(jbbcId);
	  jbbcNodeIdSet.advance(jbbcId))
  {
    if (NodeAnalysis * jbbcNode = jbbcId.getNodeAnalysis())
    {
      // Evaluate local predicates only if it is a table.

      RelExpr * jbbcExpr = jbbcNode->getOriginalExpr();

      if ((jbbcNode->getTableAnalysis() != NULL) &&
	        (jbbcExpr->getOperatorType() == REL_SCAN))
      {
        // get the original expression of the jbbc
        Scan * scanExpr = (Scan *) jbbcExpr;

        ValueIdSet localPreds = scanExpr->getSelectionPredicates();

        // if local predicates have already been computed, then skip
        if ((localPreds.entries() > 0) || !(lookup(jbbcId)))
        {
          // check to see this GA has already been associated with
          // a logExpr for synthesis.  If not, then synthesize
	        // log. expression, and then apply local predicates to it

          if (NOT scanExpr->getGroupAttr()->existsLogExprForSynthesis())
	          scanExpr->synthLogProp();

	        myEstLogProp = getStatsForCANodeId(jbbcId);
	      }
      }
    }
  }

  // Now do a second traversal of the JBB looking for join reducers
  for (jbbcId = jbbcNodeIdSet.init();
		jbbcNodeIdSet.next(jbbcId);
		jbbcNodeIdSet.advance(jbbcId))
  {
    // now look for all two way joins for this child
    if (jbbcId.getNodeAnalysis())
    {

      // get all JBBCs connected to this JBBC, and do a two-way
      // join with all of them

      CANodeIdSet connectedNodes = jbbcId.getNodeAnalysis()->\
				  getJBBC()->getJoinedJBBCs();

      for (CANodeId connectedTable = connectedNodes.init();
			      connectedNodes.next(connectedTable);
			      connectedNodes.advance(connectedTable))
      {
	      if (connectedTable.getNodeAnalysis())
	      {

	        // ASM does not concern itself with the order of the tables,
	        // hence it is possible that the join has already been computed

	        CANodeIdSet tableSet = jbbcId;
	        tableSet.insert(connectedTable);

	        if ((myEstLogProp = getCachedStatistics(&tableSet)) == NULL)
	        {
	          CANodeIdSet setForjbbcId(jbbcId);
	          CANodeIdSet setForConnectedTable(connectedTable);
	          myEstLogProp = joinJBBChildren(setForjbbcId, setForConnectedTable);
	        }
	      }
      }
    }
  }
} // AppliedStatMan::setupASMCacheForJBB

EstLogPropSharedPtr AppliedStatMan::getStatsForCANodeId(
					CANodeId jbbc,
					const EstLogPropSharedPtr &inLP,
					const ValueIdSet * predIdSet)
{

  EstLogPropSharedPtr inputLP = inLP;

  if(inputLP == (*GLOBAL_EMPTY_INPUT_LOGPROP))
    inputLP = jbbc.getJBBInput();

  EstLogPropSharedPtr outputEstLogProp = NULL;

  // 1. Try to find Logical Properties from cache if cacheable.

  // The estimate Logical Properties can be cacheable if all local
  // predicates are to be applied and if inNodeSet is provided,
  // or the inLP are cacheable

  if ((inputLP->isCacheable()) && (predIdSet == NULL) )
  {
    CANodeIdSet combinedSet = jbbc;

    // get the nodeIdSet of the outer child, if not already given. This
    // along with the present jbbc is used as a key in the cache

    CANodeIdSet * inputNodeSet;
    inputNodeSet = inputLP->getNodeSet();

    // if inLP are cacheable these should have a nodeSet attached
    CCMPASSERT(inputNodeSet != NULL);

    if (inputNodeSet)
    {
      combinedSet.insert(*inputNodeSet);
      // if estLogProp for all local predicates is required,
      // then it might already exist in the cache
      outputEstLogProp = getCachedStatistics(&combinedSet);
    }
  }

  if (outputEstLogProp == NULL)
  {
    // 2. properties do not exist in the cache, so synthesize them.

    //if specified by the user apply those predicates,
    // else apply predicates in the original expr
    NodeAnalysis * jbbcNode = jbbc.getNodeAnalysis();

    TableAnalysis * tableAnalysis = jbbcNode->getTableAnalysis();

    if (tableAnalysis && predIdSet)
    {
      TableDesc * tableDesc = tableAnalysis->getTableDesc();

      const QualifiedName& qualName = 
            tableDesc->getNATable()->getTableName();

      CorrName name(qualName, STMTHEAP);

      Scan *scanExpr = new STMTHEAP Scan(name, tableDesc, REL_SCAN, STMTHEAP);

      Cardinality rc = tableDesc->getNATable()->getEstRowCount();

      const CardinalityHint* cardHint = tableDesc->getCardinalityHint();
      if ( cardHint ) 
         rc = (cardHint->getScanCardinality()).getValue();

      if ( !cardHint && tableDesc->getNATable()->isHbaseTable() ) {

          NATable* nt = (NATable*)(tableDesc->getNATable());
   
          StatsList* statsList = nt->getColStats();
   
          if ( statsList && statsList->entries() > 0 ) {
              ColStatsSharedPtr cStatsPtr = 
                    statsList->getSingleColumnColStats(0);
   
              if ( cStatsPtr )
                 rc = (cStatsPtr->getRowcount()).getValue();
          }
      }

      scanExpr->setBaseCardinality(MIN_ONE (rc));

      GroupAttributes * gaExpr = new STMTHEAP GroupAttributes();

      scanExpr->setSelectionPredicates(*predIdSet);

      ValueIdSet requiredOutputs = jbbc.getNodeAnalysis()->\
	getOriginalExpr()->getGroupAttr()->getCharacteristicOutputs();

      gaExpr->setCharacteristicOutputs(requiredOutputs);

      scanExpr->setGroupAttr(gaExpr);
      gaExpr->setLogExprForSynthesis(scanExpr);

      EstLogPropSharedPtr nonCacheableInLP(new (HISTHEAP) EstLogProp (*inputLP));
      nonCacheableInLP->setCacheableFlag(FALSE);
      scanExpr->synthLogProp();
//.........这里部分代码省略.........