~drizzle-trunk/drizzle/development

/* Copyright (C) 2005 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; 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#ifndef RPL_RLI_H

#define RPL_RLI_H

#include "rpl_tblmap.h"

#include "rpl_reporting.h"

#include "rpl_utility.h"

struct RPL_TableList;

class Master_info;

/****************************************************************************

  Replication SQL Thread

  Relay_log_info contains:

    - the current relay log

    - the current relay log offset

    - master log name

    - master log sequence corresponding to the last update

    - misc information specific to the SQL thread

  Relay_log_info is initialized from the slave.info file if such

  exists.  Otherwise, data members are intialized with defaults. The

  initialization is done with init_relay_log_info() call.

  The format of slave.info file:

  relay_log_name

  relay_log_pos

  master_log_name

  master_log_pos

  To clean up, call end_relay_log_info()

*****************************************************************************/

class Relay_log_info : public Slave_reporting_capability

{

public:

  /**

     Flags for the state of the replication.

   */

  enum enum_state_flag {

    /** The replication thread is inside a statement */

    IN_STMT,

    /** Flag counter.  Should always be last */

    STATE_FLAGS_COUNT

  };

  /*

    If flag set, then rli does not store its state in any info file.

    This is the case only when we execute BINLOG SQL commands inside

    a client, non-replication thread.

  */

  bool no_storage;

  /*

    If true, events with the same server id should be replicated. This

    field is set on creation of a relay log info structure by copying

    the value of ::replicate_same_server_id and can be overridden if

    necessary. For example of when this is done, check sql_binlog.cc,

    where the BINLOG statement can be used to execute "raw" events.

   */

  bool replicate_same_server_id;

  /*** The following variables can only be read when protect by data lock ****/

  /*

    info_fd - file descriptor of the info file. set only during

    initialization or clean up - safe to read anytime

    cur_log_fd - file descriptor of the current read  relay log

  */

  File info_fd,cur_log_fd;

  /*

    Protected with internal locks.

    Must get data_lock when resetting the logs.

  */

  DRIZZLE_BIN_LOG relay_log;

  LOG_INFO linfo;

  IO_CACHE cache_buf,*cur_log;

  /* The following variables are safe to read any time */

  /* IO_CACHE of the info file - set only during init or end */

  IO_CACHE info_file;

  /*

    When we restart slave thread we need to have access to the previously

    created temporary tables. Modified only on init/end and by the SQL

    thread, read only by SQL thread.

  */

  Table *save_temporary_tables;

  /*

    standard lock acquistion order to avoid deadlocks:

    run_lock, data_lock, relay_log.LOCK_log, relay_log.LOCK_index

  */

  pthread_mutex_t data_lock,run_lock;

  /*

    start_cond is broadcast when SQL thread is started

    stop_cond - when stopped

    data_cond - when data protected by data_lock changes

  */

  pthread_cond_t start_cond, stop_cond, data_cond;

  /* parent Master_info structure */

  Master_info *mi;

  /*

    Needed to deal properly with cur_log getting closed and re-opened with

    a different log under our feet

  */

  uint32_t cur_log_old_open_count;

  /*

    Let's call a group (of events) :

      - a transaction

      or

      - an autocommiting query + its associated events (INSERT_ID,

    TIMESTAMP...)

    We need these rli coordinates :

    - relay log name and position of the beginning of the group we currently are

    executing. Needed to know where we have to restart when replication has

    stopped in the middle of a group (which has been rolled back by the slave).

    - relay log name and position just after the event we have just

    executed. This event is part of the current group.

    Formerly we only had the immediately above coordinates, plus a 'pending'

    variable, but this dealt wrong with the case of a transaction starting on a

    relay log and finishing (commiting) on another relay log. Case which can

    happen when, for example, the relay log gets rotated because of

    max_binlog_size.

  */

  char group_relay_log_name[FN_REFLEN];

  uint64_t group_relay_log_pos;

  char event_relay_log_name[FN_REFLEN];

  uint64_t event_relay_log_pos;

  uint64_t future_event_relay_log_pos;

#ifdef HAVE_purify

  bool is_fake; /* Mark that this is a fake relay log info structure */

#endif

  /* 

     Original log name and position of the group we're currently executing

     (whose coordinates are group_relay_log_name/pos in the relay log)

     in the master's binlog. These concern the *group*, because in the master's

     binlog the log_pos that comes with each event is the position of the

     beginning of the group.

  */

  char group_master_log_name[FN_REFLEN];

  volatile my_off_t group_master_log_pos;

  /*

    Handling of the relay_log_space_limit optional constraint.

    ignore_log_space_limit is used to resolve a deadlock between I/O and SQL

    threads, the SQL thread sets it to unblock the I/O thread and make it

    temporarily forget about the constraint.

  */

  uint64_t log_space_limit,log_space_total;

  bool ignore_log_space_limit;

  /*

    When it commits, InnoDB internally stores the master log position it has

    processed so far; the position to store is the one of the end of the

    committing event (the COMMIT query event, or the event if in autocommit

    mode).

  */

  uint64_t future_group_master_log_pos;

  time_t last_master_timestamp;

  void clear_until_condition();

  /*

    Needed for problems when slave stops and we want to restart it

    skipping one or more events in the master log that have caused

    errors, and have been manually applied by DBA already.

  */

  volatile uint32_t slave_skip_counter;

  volatile uint32_t abort_pos_wait;	/* Incremented on change master */

  volatile uint32_t slave_run_id;		/* Incremented on slave start */

  pthread_mutex_t log_space_lock;

  pthread_cond_t log_space_cond;

  THD * sql_thd;

  int32_t events_till_abort;

  /* if not set, the value of other members of the structure are undefined */

  bool inited;

  volatile bool abort_slave;

  volatile uint32_t slave_running;

  /* 

     Condition and its parameters from START SLAVE UNTIL clause.

     UNTIL condition is tested with is_until_satisfied() method that is 

     called by exec_relay_log_event(). is_until_satisfied() caches the result

     of the comparison of log names because log names don't change very often;

     this cache is invalidated by parts of code which change log names with

     notify_*_log_name_updated() methods. (They need to be called only if SQL

     thread is running).

   */

  enum {UNTIL_NONE= 0, UNTIL_MASTER_POS, UNTIL_RELAY_POS} until_condition;

  char until_log_name[FN_REFLEN];

  uint64_t until_log_pos;

  /* extension extracted from log_name and converted to int32_t */

  uint32_t until_log_name_extension;   

  /* 

     Cached result of comparison of until_log_name and current log name

     -2 means unitialised, -1,0,1 are comarison results 

  */

  enum 

  { 

    UNTIL_LOG_NAMES_CMP_UNKNOWN= -2, UNTIL_LOG_NAMES_CMP_LESS= -1,

    UNTIL_LOG_NAMES_CMP_EQUAL= 0, UNTIL_LOG_NAMES_CMP_GREATER= 1

  } until_log_names_cmp_result;

  char cached_charset[6];

  /*

    trans_retries varies between 0 to slave_transaction_retries and counts how

    many times the slave has retried the present transaction; gets reset to 0

    when the transaction finally succeeds. retried_trans is a cumulative

    counter: how many times the slave has retried a transaction (any) since

    slave started.

  */

  uint32_t trans_retries, retried_trans;

  /*

    If the end of the hot relay log is made of master's events ignored by the

    slave I/O thread, these two keep track of the coords (in the master's

    binlog) of the last of these events seen by the slave I/O thread. If not,

    ign_master_log_name_end[0] == 0.

    As they are like a Rotate event read/written from/to the relay log, they

    are both protected by rli->relay_log.LOCK_log.

  */

  char ign_master_log_name_end[FN_REFLEN];

  uint64_t ign_master_log_pos_end;

  Relay_log_info();

  ~Relay_log_info();

  /*

    Invalidate cached until_log_name and group_relay_log_name comparison 

    result. Should be called after any update of group_realy_log_name if

    there chances that sql_thread is running.

  */

  inline void notify_group_relay_log_name_update()

  {

    if (until_condition==UNTIL_RELAY_POS)

      until_log_names_cmp_result= UNTIL_LOG_NAMES_CMP_UNKNOWN;

  }

  /*

    The same as previous but for group_master_log_name. 

  */

  inline void notify_group_master_log_name_update()

  {

    if (until_condition==UNTIL_MASTER_POS)

      until_log_names_cmp_result= UNTIL_LOG_NAMES_CMP_UNKNOWN;

  }

  inline void inc_event_relay_log_pos()

  {

    event_relay_log_pos= future_event_relay_log_pos;

  }

  void inc_group_relay_log_pos(uint64_t log_pos,

			       bool skip_lock=0);

  int32_t wait_for_pos(THD* thd, String* log_name, int64_t log_pos, 

		   int64_t timeout);

  void close_temporary_tables();

  /* Check if UNTIL condition is satisfied. See slave.cc for more. */

  bool is_until_satisfied(my_off_t master_beg_pos);

  inline uint64_t until_pos()

  {

    return ((until_condition == UNTIL_MASTER_POS) ? group_master_log_pos :

	    group_relay_log_pos);

  }

  RPL_TableList *tables_to_lock;           /* RBR: Tables to lock  */

  uint32_t tables_to_lock_count;        /* RBR: Count of tables to lock */

  table_mapping m_table_map;      /* RBR: Mapping table-id to table */

  inline table_def *get_tabledef(Table *tbl)

  {

    table_def *td= 0;

    for (TableList *ptr= tables_to_lock; ptr && !td; ptr= ptr->next_global)

      if (ptr->table == tbl)

        td= &((RPL_TableList *)ptr)->m_tabledef;

    return (td);

  }

  /*

    Last charset (6 bytes) seen by slave SQL thread is cached here; it helps

    the thread save 3 get_charset() per Query_log_event if the charset is not

    changing from event to event (common situation).

    When the 6 bytes are equal to 0 is used to mean "cache is invalidated".

  */

  void cached_charset_invalidate();

  bool cached_charset_compare(char *charset) const;

  void cleanup_context(THD *, bool);

  void clear_tables_to_lock();

  /*

    Used by row-based replication to detect that it should not stop at

    this event, but give it a chance to send more events. The time

    where the last event inside a group started is stored here. If the

    variable is zero, we are not in a group (but may be in a

    transaction).

   */

  time_t last_event_start_time;

  /**

    Helper function to do after statement completion.

    This function is called from an event to complete the group by

    either stepping the group position, if the "statement" is not

    inside a transaction; or increase the event position, if the

    "statement" is inside a transaction.

    @param event_log_pos

    Master log position of the event. The position is recorded in the

    relay log info and used to produce information for <code>SHOW

    SLAVE STATUS</code>.

    @param event_creation_time

    Timestamp for the creation of the event on the master side. The

    time stamp is recorded in the relay log info and used to compute

    the <code>Seconds_behind_master</code> field.

  */

  void stmt_done(my_off_t event_log_pos,

                 time_t event_creation_time);

  /**

     Set the value of a replication state flag.

     @param flag Flag to set

   */

  void set_flag(enum_state_flag flag)

  {

    m_flags |= (1UL << flag);

  }

  /**

     Get the value of a replication state flag.

     @param flag Flag to get value of

     @return @c true if the flag was set, @c false otherwise.

   */

  bool get_flag(enum_state_flag flag)

  {

    return m_flags & (1UL << flag);

  }

  /**

     Clear the value of a replication state flag.

     @param flag Flag to clear

   */

  void clear_flag(enum_state_flag flag)

  {

    m_flags &= ~(1UL << flag);

  }

  /**

     Is the replication inside a group?

     Replication is inside a group if either:

     - The OPTION_BEGIN flag is set, meaning we're inside a transaction

     - The RLI_IN_STMT flag is set, meaning we're inside a statement

     @retval true Replication thread is currently inside a group

     @retval false Replication thread is currently not inside a group

   */

  bool is_in_group() const {

    return (sql_thd->options & OPTION_BEGIN) ||

      (m_flags & (1UL << IN_STMT));

  }

private:

  uint32_t m_flags;

};

// Defined in rpl_rli.cc

int32_t init_relay_log_info(Relay_log_info* rli, const char* info_fname);

#endif /* RPL_RLI_H */