NdbScanOperation.hpp

/* Copyright (C) 2003 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef NdbScanOperation_H
#define NdbScanOperation_H

#include <NdbOperation.hpp>

class NdbBlob;
class NdbResultSet;
class PollGuard;

/**
 * @class NdbScanOperation
 * @brief Class of scan operations for use in transactions.  
 */
class NdbScanOperation : public NdbOperation {
#ifndef DOXYGEN_SHOULD_SKIP_INTERNAL
  friend class Ndb;
  friend class NdbTransaction;
  friend class NdbResultSet;
  friend class NdbOperation;
  friend class NdbBlob;
#endif

public:
  /**
   * Scan flags.  OR-ed together and passed as second argument to
   * readTuples.
   */
  enum ScanFlag {
    SF_TupScan = (1 << 16),     // scan TUP - only LM_CommittedRead
    SF_OrderBy = (1 << 24),     // index scan in order
    SF_Descending = (2 << 24),  // index scan in descending order
    SF_ReadRangeNo = (4 << 24)  // enable @ref get_range_no
  };

  /**
   * readTuples
   * 
   * @param lock_mode Lock mode
   * @param scan_flags see @ref ScanFlag
   * @param parallel No of fragments to scan in parallel (0=max)
   */ 
  virtual
  int readTuples(LockMode lock_mode = LM_Read, 
                 Uint32 scan_flags = 0, Uint32 parallel = 0);

#ifndef DOXYGEN_SHOULD_SKIP_DEPRECATED
  /**
   * readTuples
   * 
   * @param lock_mode Lock mode
   * @param batch No of rows to fetch from each fragment at a time
   * @param parallel No of fragments to scan in parallell
   * @note specifying 0 for batch and parallall means max performance
   */ 
#ifdef ndb_readtuples_impossible_overload
  int readTuples(LockMode lock_mode = LM_Read, 
		 Uint32 batch = 0, Uint32 parallel = 0);
#endif
  
  inline int readTuples(int parallell){
    return readTuples(LM_Read, 0, parallell);
  }
  
  inline int readTuplesExclusive(int parallell = 0){
    return readTuples(LM_Exclusive, 0, parallell);
  }
#endif
  
#ifndef DOXYGEN_SHOULD_SKIP_INTERNAL
  NdbBlob* getBlobHandle(const char* anAttrName);
  NdbBlob* getBlobHandle(Uint32 anAttrId);
#endif

  /**
   * Get the next tuple in a scan transaction. 
   * 
   * After each call to nextResult
   * the buffers and NdbRecAttr objects defined in 
   * NdbOperation::getValue are updated with values 
   * from the scanned tuple. 
   *
   * @param fetchAllowed  If set to false, then fetching is disabled
   * @param forceSend If true send will occur immediately (see @ref secAdapt)
   *
   * The NDB API will contact the NDB Kernel for more tuples 
   * when necessary to do so unless you set the fetchAllowed 
   * to false. 
   * This will force NDB to process any records it
   * already has in it's caches. When there are no more cached 
   * records it will return 2. You must then call nextResult
   * with fetchAllowed = true in order to contact NDB for more 
   * records.
   *
   * fetchAllowed = false is useful when you want to update or 
   * delete all the records fetched in one transaction(This will save a
   *  lot of round trip time and make updates or deletes of scanned 
   * records a lot faster). 
   * While nextResult(false)
   * returns 0 take over the record to another transaction. When 
   * nextResult(false) returns 2 you must execute and commit the other 
   * transaction. This will cause the locks to be transferred to the 
   * other transaction, updates or deletes will be made and then the 
   * locks will be released.
   * After that, call nextResult(true) which will fetch new records and
   * cache them in the NdbApi. 
   * 
   * @note  If you don't take over the records to another transaction the 
   *        locks on those records will be released the next time NDB Kernel
   *        is contacted for more records.
   *
   * @note  Please contact for examples of efficient scan
   *        updates and deletes.
   * 
   * @note  See ndb/examples/ndbapi_scan_example for usage.
   *
   * @return 
   * -  -1: if unsuccessful,<br>
   * -   0: if another tuple was received, and<br> 
   * -   1: if there are no more tuples to scan.
   * -   2: if there are no more cached records in NdbApi
   */
  int nextResult(bool fetchAllowed = true, bool forceSend = false);

  /**
   * Close scan
   */
  void close(bool forceSend = false, bool releaseOp = false);

  /**
   * Update current tuple
   *
   * @return an NdbOperation or NULL.
   */
  NdbOperation* updateCurrentTuple();
  /**
   * Update current tuple
   *
   * @param updateTrans Transaction that should perform the update
   *
   * @return an NdbOperation or NULL.
   */
  NdbOperation*	updateCurrentTuple(NdbTransaction* updateTrans);

  /**
   * Delete current tuple
   * @return 0 on success or -1 on failure
   */
  int deleteCurrentTuple();
  /**
   * Delete current tuple
   *
   * @param takeOverTransaction Transaction that should perform the delete
   *
   * @return 0 on success or -1 on failure
   */
  int deleteCurrentTuple(NdbTransaction* takeOverTransaction);
  
  /**
   * Restart scan with exactly the same
   *   getValues and search conditions
   */
  int restart(bool forceSend = false);
  
protected:
  NdbScanOperation(Ndb* aNdb);
  virtual ~NdbScanOperation();

  int nextResultImpl(bool fetchAllowed = true, bool forceSend = false);
  virtual void release();
  
  int close_impl(class TransporterFacade*, bool forceSend,
                 PollGuard *poll_guard);

  // Overloaded methods from NdbCursorOperation
  int executeCursor(int ProcessorId);

  // Overloaded private methods from NdbOperation
  int init(const NdbTableImpl* tab, NdbTransaction*);
  int prepareSend(Uint32  TC_ConnectPtr, Uint64  TransactionId);
  int doSend(int ProcessorId);

  virtual void setErrorCode(int aErrorCode);
  virtual void setErrorCodeAbort(int aErrorCode);

  NdbTransaction *m_transConnection;

  // Scan related variables
  Uint32 theParallelism;
  Uint32 m_keyInfo;

  int getFirstATTRINFOScan();
  int doSendScan(int ProcessorId);
  int prepareSendScan(Uint32 TC_ConnectPtr, Uint64 TransactionId);
  
  int fix_receivers(Uint32 parallel);
  void reset_receivers(Uint32 parallel, Uint32 ordered);
  Uint32* m_array; // containing all arrays below
  Uint32 m_allocated_receivers;
  NdbReceiver** m_receivers;      // All receivers

  Uint32* m_prepared_receivers;   // These are to be sent

  /**
   * owned by API/user thread
   */
  Uint32 m_current_api_receiver;
  Uint32 m_api_receivers_count;
  NdbReceiver** m_api_receivers;  // These are currently used by api
  
  /**
   * owned by receiver thread
   */
  Uint32 m_conf_receivers_count;  // NOTE needs mutex to access
  NdbReceiver** m_conf_receivers; // receive thread puts them here
  
  /**
   * owned by receiver thread
   */
  Uint32 m_sent_receivers_count;  // NOTE needs mutex to access
  NdbReceiver** m_sent_receivers; // receive thread puts them here
  
  int send_next_scan(Uint32 cnt, bool close);
  void receiver_delivered(NdbReceiver*);
  void receiver_completed(NdbReceiver*);
  void execCLOSE_SCAN_REP();

  int getKeyFromKEYINFO20(Uint32* data, unsigned size);
  NdbOperation*	takeOverScanOp(OperationType opType, NdbTransaction*);
  
  bool m_ordered;
  bool m_descending;
  Uint32 m_read_range_no;
  NdbRecAttr *m_curr_row; // Pointer to last returned row
  bool m_executed; // Marker if operation should be released at close
};

inline
NdbOperation* 
NdbScanOperation::updateCurrentTuple(){
  return updateCurrentTuple(m_transConnection);
}

inline
NdbOperation* 
NdbScanOperation::updateCurrentTuple(NdbTransaction* takeOverTrans){
  return takeOverScanOp(NdbOperation::UpdateRequest, 
			takeOverTrans);
}

inline
int
NdbScanOperation::deleteCurrentTuple(){
  return deleteCurrentTuple(m_transConnection);
}

inline
int
NdbScanOperation::deleteCurrentTuple(NdbTransaction * takeOverTrans){
  void * res = takeOverScanOp(NdbOperation::DeleteRequest, 
			      takeOverTrans);
  if(res == 0)
    return -1;
  return 0;
}

#endif