mysql5/mysql-5.7.27/sql/rpl_info.h

/* Copyright (c) 2010, 2016, Oracle and/or its affiliates. All rights reserved.

   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 RPL_INFO_H
#define RPL_INFO_H

#include "my_global.h"
#include "mysql_com.h"            // NAME_LEN
#include "rpl_info_handler.h"     // Rpl_info_handler
#include "rpl_reporting.h"        // Slave_reporting_capability
#include "atomic_class.h"         // Atomic_int32


#define  CHANNEL_NAME_LENGTH NAME_LEN

class Rpl_info : public Slave_reporting_capability
{
public:
  virtual ~Rpl_info();

  /*
    standard lock acquisition order to avoid deadlocks:
    run_lock, data_lock, relay_log.LOCK_log, relay_log.LOCK_index
    run_lock, sleep_lock
    run_lock, info_thd_lock

    info_thd_lock is to protect operations on info_thd:
    - before *reading* info_thd we must hold *either* info_thd_lock or
      run_lock;
    - before *writing* we must hold *both* run_lock and info_thd_lock.
  */
  mysql_mutex_t data_lock, run_lock, sleep_lock, info_thd_lock;
  /*
    start_cond is broadcast when SQL thread is started
    stop_cond  - when stopped
    data_cond  - when data protected by data_lock changes
    sleep_cond - when killed

    'data_cond' is only being used in class Relay_log_info and not in the
    class Master_info. So 'data_cond' could be moved to Relay_log_info.
  */
  mysql_cond_t data_cond, start_cond, stop_cond, sleep_cond;

#ifdef HAVE_PSI_INTERFACE
  PSI_mutex_key *key_info_run_lock, *key_info_data_lock, *key_info_sleep_lock,
                *key_info_thd_lock;

  PSI_mutex_key *key_info_data_cond, *key_info_start_cond, *key_info_stop_cond,
                *key_info_sleep_cond;
#endif

  THD *info_thd;

  bool inited;
  volatile bool abort_slave;
  volatile uint slave_running;
  volatile ulong slave_run_id;

#ifndef DBUG_OFF
  int events_until_exit;
#endif

  /**
    Sets the persistency component/handler.

    @param[in] hanlder Pointer to the handler.
  */ 
  void set_rpl_info_handler(Rpl_info_handler * param_handler)
  {
    handler= param_handler;
  }

  /**
    Gets the persistency component/handler.

    @return the handler if there is one.
  */ 
  Rpl_info_handler *get_rpl_info_handler()
  {
    return (handler);
  }

  enum_return_check check_info()
  {
    return (handler->check_info());
  }

  int remove_info()
  {
    return (handler->remove_info());
  }

  int clean_info()
  {
    return (handler->clean_info());
  }

  bool is_transactional()
  {
    return (handler->is_transactional());
  }

  bool update_is_transactional()
  {
    return (handler->update_is_transactional());
  }

  char *get_description_info()
  {
    return (handler->get_description_info());
  }

  bool copy_info(Rpl_info_handler *from, Rpl_info_handler *to)
  {
    if (read_info(from) || write_info(to))
      return(TRUE);

    return(FALSE);
  }

  uint get_internal_id()
  {
    return internal_id;
  }

  char *get_channel()
  {
    return channel;
  }

 /**
   To search in the slave repositories, each slave info object
   (mi, rli or worker) should use a primary key. This function
   sets the field values of the slave info objects with
   the search information, which is nothing but PK in mysql slave
   info tables.
   Ex: field_value[23]="channel_name" in the master info
   object.

   Currently, used only for TABLE repository.
*/

 virtual bool set_info_search_keys(Rpl_info_handler *to)= 0;

protected:
  /**
    Pointer to the repository's handler.
  */
  Rpl_info_handler *handler;

  /**
    Uniquely and internaly identifies an info entry (.e.g. a row or
    file). This information is completely transparent to users and
    is used only during startup to retrieve information from the
    repositories.

    @todo, This is not anymore required for Master_info and
           Relay_log_info, since Channel can be used to uniquely
           identify this. To preserve backward compatibility,
           we keep this for Master_info and Relay_log_info.
           However, {id, channel} is still required for a worker info.
  */
  uint internal_id;

  /**
     Every slave info object acts on a particular channel in Multisource
     Replication.
  */
  char channel[CHANNEL_NAME_LENGTH+1];

  Rpl_info(const char* type
#ifdef HAVE_PSI_INTERFACE
           ,PSI_mutex_key *param_key_info_run_lock,
           PSI_mutex_key *param_key_info_data_lock,
           PSI_mutex_key *param_key_info_sleep_lock,
           PSI_mutex_key *param_key_info_thd_lock,
           PSI_mutex_key *param_key_info_data_cond,
           PSI_mutex_key *param_key_info_start_cond,
           PSI_mutex_key *param_key_info_stop_cond,
           PSI_mutex_key *param_key_info_sleep_cond
#endif
           ,uint param_id, const char* param_channel
          );

private:
  virtual bool read_info(Rpl_info_handler *from)= 0;
  virtual bool write_info(Rpl_info_handler *to)= 0;

  Rpl_info(const Rpl_info& info);
  Rpl_info& operator=(const Rpl_info& info);

public:
  /* True when the thread is still running, but started the stop procedure */
  Atomic_int32 is_stopping;
};
#endif /* RPL_INFO_H */