core/sql/optimizer/QueryRewriteHandler.h

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#ifndef QUERYREWERITEHANDLER_H
#define QUERYREWERITEHANDLER_H
/* -*-C++-*-
 **************************************************************************
 *
 * File:         QueryRewriteHandler.h
 * Description:  MvQueryRewriteHandler class and methods
 * Created:      02/14/2008
 * Language:     C++
 *
 **************************************************************************
 */

#include "Analyzer.h"
#include "XMLUtil.h"

class QRMVDescriptor;
class QRXmlMessageObj;

//============================================================================
class MvQueryRewriteHandler : public NABasicObject
{ 
public:
  MvQueryRewriteHandler(CollHeap* heap)
    : mvName_(heap),
      mvDescriptor_(NULL),
      formatXml_(TRUE),
      warningMessage_(heap)
  {}

  // Methods called by CatMan during CREATE MV
  QRMVDescriptorPtr getMvDescriptor() { return mvDescriptor_; }

  // Methods called by the Analyzer
  void createMvDescriptor(QueryAnalysis* qa, RelExpr* expr, NAString& warningMessage);
  RelExpr* handleMvQueryRewrite(QueryAnalysis* qa, RelExpr* expr, NAString& warningMessage);

  void dumpToFile(const char* fileName, const char* data);
  //void dumpAnalysisToFile(QueryAnalysis* qa, RelExpr* expr);

  /**
   * Determines whether query rewrite is worth pursuing for the current query.
   * This decision is based on the nature and complexity of the query.
   *
   * @param rootExpr The pointer to the query root node.
   * @return \c TRUE iff the query appears likely to benefit from looking for
   *         MVs to use in rewriting it.
   */
  static NABoolean rewriteWorthTrying(RelRoot* rootExpr);

  NABoolean isMvqrSupportedForMV(QueryAnalysis* qa, RelExpr* expr, NAString& warningMessage);
  
  NAString& getWarningMessage() 
  { 
    return warningMessage_; 
  }

protected:
  RelRoot* handleAnalyzeOnlyQuery(RelRoot* rootExpr, NAString* xmlText);
  RelRoot* handleAnalyzeOnlyQuery(RelRoot* rootExpr, const char* excuse);

private:
  // Details about the MV, to be written into the descriptor
  NAString      mvName_;
  NABoolean     isIncremental_;
  NABoolean     isImmediate_;

  QRMVDescriptorPtr mvDescriptor_;
  NABoolean     formatXml_;
  XMLString*    xmlText_;
  NAString      warningMessage_;
};  // MvQueryRewriteHandler

#endif // QUERYREWERITEHANDLER_H