rpl_info.h

/* Copyright (c) 2010, 2024, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is designed to work with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have either included with
   the program or referenced in the documentation.

   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, version 2.0, 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 <sys/types.h>
#include <atomic>

#include "my_inttypes.h"
#include "my_psi_config.h"
#include "mysql/components/services/bits/mysql_cond_bits.h"
#include "mysql/components/services/bits/mysql_mutex_bits.h"
#include "mysql/components/services/bits/psi_mutex_bits.h"
#include "mysql_com.h"             // NAME_LEN
#include "sql/rpl_info_handler.h"  // Rpl_info_handler
#include "sql/rpl_reporting.h"     // Slave_reporting_capability

class THD;

#define CHANNEL_NAME_LENGTH NAME_LEN

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

  /*
    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;
  std::atomic<bool> abort_slave;
  std::atomic<uint> slave_running;
  std::atomic<ulong> slave_run_id;

  /**
    Sets the persistency component/handler.

    @param[in] param_handler 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() const { return (handler->check_info()); }

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

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

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

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

  char *get_description_info() const {
    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() const { return internal_id; }

  char *get_channel() const { return const_cast<char *>(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 internally 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 required any longer 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] = {0};

  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 */
  std::atomic<bool> atomic_is_stopping{false};
};
#endif /* RPL_INFO_H */