NdbPoolImpl.hpp

/*
   Copyright (C) 2003, 2005, 2006 MySQL AB
    All rights reserved. Use is subject to license terms.

   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; version 2 of the License.

   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#ifndef NdbPool_H
#define NdbPool_H

#include <Ndb.hpp>
#include <NdbMutex.h>
#include <NdbCondition.h>
#include <NdbOut.hpp>

class NdbPool {
#define NULL_POOL 0
#define NULL_HASH 0xFF
#define POOL_HASH_TABLE_SIZE 32
#define MAX_NDB_OBJECTS 240
  struct POOL_STRUCT {
    Ndb* ndb_reference;
    bool in_use;
    bool free_entry;
    Uint16 next_free_object;
    Uint16 prev_free_object;
    Uint16 next_db_object;
    Uint16 prev_db_object;
  };
  public:
    static NdbPool* create_instance(Ndb_cluster_connection*,
                                    Uint32 max_ndb_objects = 240,
                                    Uint32 no_conn_obj = 4,
                                    Uint32 init_no_ndb_objects = 8);
    static void drop_instance();
    Ndb* get_ndb_object(Uint32 &hint_id,
                        const char* a_catalog_name,
                        const char* a_schema_name);
    void return_ndb_object(Ndb* returned_object, Uint32 id);
  private:
    bool init(Uint32 initial_no_of_ndb_objects = 8);
    void release_all();
    static bool initPoolMutex();
    NdbPool(Ndb_cluster_connection*, 
            Uint32 max_no_of_ndb_objects, Uint32 no_conn_objects);
    ~NdbPool();
  /*
  We have three lists:
  1) A list for entries not in use
  2) A list for free entries
  3) A hash table with schema name and database name as key

  These lists are all initialised in the init call.
  The list for entries not in use is very simple since the current
  implementation have not yet any handling of dropping Ndb objects
  until all Ndb objects are dropped.
  */
    void add_free_list(Uint32 id);
    void remove_free_list(Uint32 id);
    Ndb* get_free_list(Uint32 &id, Uint32 hash_entry);

    void add_db_hash(Uint32 id);
    void remove_db_hash(Uint32 id, Uint32 hash_entry);
    Ndb* get_db_hash(Uint32 &id,
                     Uint32 hash_entry,
                     const char* a_catalog_name,
                     const char* a_schema_name);

    bool allocate_ndb(Uint32 &id,
                      const char* a_catalog_name,
                      const char* a_schema_name);
    Ndb* get_hint_ndb(Uint32 id, Uint32 hash_entry);
    Ndb* wait_free_ndb(Uint32 &id);
    Uint32 compute_hash(const char *a_schema_name);
    void add_wait_list(Uint32 id);
    void remove_wait_list();
    void switch_condition_queue();

    static NdbMutex     *pool_mutex;
    struct NdbCondition *input_pool_cond;
    struct NdbCondition *output_pool_cond;

    POOL_STRUCT *m_pool_reference;
    Uint8       *m_hash_entry;

    bool        m_inited;
    Uint32      m_no_of_conn_objects;

    Uint16      m_no_of_objects;
    Uint16      m_max_ndb_objects;
    Uint16      m_first_free;
    Uint16      m_last_free;
    Uint16      m_first_not_in_use;
    Uint16      m_waiting;
    Uint16      m_first_wait;
    Uint16      m_input_queue;
    Uint16      m_output_queue;
    Uint16      m_signal_count;

  Ndb_cluster_connection * m_cluster_connection;
};
#endif