~drizzle-trunk/drizzle/development : contents of sql/log.cc at revision 77.1.18

~drizzle-trunk/drizzle/development : (revision 77.1.18)
/* Copyright (C) 2000-2003 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; 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 */


/**
  @file

  @brief
  logging of commands

  @todo
    Abort logging when we get an error in reading or writing log files
*/

#include "mysql_priv.h"
#include "sql_repl.h"
#include "rpl_filter.h"
#include "rpl_rli.h"

#include <my_dir.h>
#include <stdarg.h>
#include <m_ctype.h>				// For test_if_number

#include <mysql/plugin.h>

/* max size of the log message */
#define MAX_LOG_BUFFER_SIZE 1024
#define MAX_USER_HOST_SIZE 512
#define MAX_TIME_SIZE 32
#define MY_OFF_T_UNDEF (~(my_off_t)0UL)

#define FLAGSTR(V,F) ((V)&(F)?#F" ":"")

LOGGER logger;

MYSQL_BIN_LOG mysql_bin_log;
ulong sync_binlog_counter= 0;

static bool test_if_number(const char *str,
			   long *res, bool allow_wildcards);
static int binlog_init(void *p);
static int binlog_close_connection(handlerton *hton, THD *thd);
static int binlog_savepoint_set(handlerton *hton, THD *thd, void *sv);
static int binlog_savepoint_rollback(handlerton *hton, THD *thd, void *sv);
static int binlog_commit(handlerton *hton, THD *thd, bool all);
static int binlog_rollback(handlerton *hton, THD *thd, bool all);
static int binlog_prepare(handlerton *hton, THD *thd, bool all);

/**
  Silence all errors and warnings reported when performing a write
  to a log table.
  Errors and warnings are not reported to the client or SQL exception
  handlers, so that the presence of logging does not interfere and affect
  the logic of an application.
*/
class Silence_log_table_errors : public Internal_error_handler
{
  char m_message[MYSQL_ERRMSG_SIZE];
public:
  Silence_log_table_errors()
  {
    m_message[0]= '\0';
  }

  virtual ~Silence_log_table_errors() {}

  virtual bool handle_error(uint sql_errno, const char *message,
                            MYSQL_ERROR::enum_warning_level level,
                            THD *thd);
  const char *message() const { return m_message; }
};

bool
Silence_log_table_errors::handle_error(uint /* sql_errno */,
                                       const char *message_arg,
                                       MYSQL_ERROR::enum_warning_level /* level */,
                                       THD * /* thd */)
{
  strmake(m_message, message_arg, sizeof(m_message)-1);
  return TRUE;
}


sql_print_message_func sql_print_message_handlers[3] =
{
  sql_print_information,
  sql_print_warning,
  sql_print_error
};


char *make_default_log_name(char *buff,const char* log_ext)
{
  strmake(buff, pidfile_name, FN_REFLEN-5);
  return fn_format(buff, buff, mysql_data_home, log_ext,
                   MYF(MY_UNPACK_FILENAME|MY_REPLACE_EXT));
}

/*
  Helper class to hold a mutex for the duration of the
  block.

  Eliminates the need for explicit unlocking of mutexes on, e.g.,
  error returns.  On passing a null pointer, the sentry will not do
  anything.
 */
class Mutex_sentry
{
public:
  Mutex_sentry(pthread_mutex_t *mutex)
    : m_mutex(mutex)
  {
    if (m_mutex)
      pthread_mutex_lock(mutex);
  }

  ~Mutex_sentry()
  {
    if (m_mutex)
      pthread_mutex_unlock(m_mutex);
#ifndef DBUG_OFF
    m_mutex= 0;
#endif
  }

private:
  pthread_mutex_t *m_mutex;

  // It's not allowed to copy this object in any way
  Mutex_sentry(Mutex_sentry const&);
  void operator=(Mutex_sentry const&);
};

/*
  Helper class to store binary log transaction data.
*/
class binlog_trx_data {
public:
  binlog_trx_data()
    : at_least_one_stmt(0), m_pending(0), before_stmt_pos(MY_OFF_T_UNDEF)
  {
    trans_log.end_of_file= max_binlog_cache_size;
  }

  ~binlog_trx_data()
  {
    DBUG_ASSERT(pending() == NULL);
    close_cached_file(&trans_log);
  }

  my_off_t position() const {
    return my_b_tell(&trans_log);
  }

  bool empty() const
  {
    return pending() == NULL && my_b_tell(&trans_log) == 0;
  }

  /*
    Truncate the transaction cache to a certain position. This
    includes deleting the pending event.
   */
  void truncate(my_off_t pos)
  {
    DBUG_PRINT("info", ("truncating to position %lu", (ulong) pos));
    DBUG_PRINT("info", ("before_stmt_pos=%lu", (ulong) pos));
    delete pending();
    set_pending(0);
    reinit_io_cache(&trans_log, WRITE_CACHE, pos, 0, 0);
    if (pos < before_stmt_pos)
      before_stmt_pos= MY_OFF_T_UNDEF;

    /*
      The only valid positions that can be truncated to are at the
      beginning of a statement. We are relying on this fact to be able
      to set the at_least_one_stmt flag correctly. In other word, if
      we are truncating to the beginning of the transaction cache,
      there will be no statements in the cache, otherwhise, we will
      have at least one statement in the transaction cache.
     */
    at_least_one_stmt= (pos > 0);
  }

  /*
    Reset the entire contents of the transaction cache, emptying it
    completely.
   */
  void reset() {
    if (!empty())
      truncate(0);
    before_stmt_pos= MY_OFF_T_UNDEF;
    trans_log.end_of_file= max_binlog_cache_size;
  }

  Rows_log_event *pending() const
  {
    return m_pending;
  }

  void set_pending(Rows_log_event *const pending)
  {
    m_pending= pending;
  }

  IO_CACHE trans_log;                         // The transaction cache

  /**
    Boolean that is true if there is at least one statement in the
    transaction cache.
  */
  bool at_least_one_stmt;

private:
  /*
    Pending binrows event. This event is the event where the rows are
    currently written.
   */
  Rows_log_event *m_pending;

public:
  /*
    Binlog position before the start of the current statement.
  */
  my_off_t before_stmt_pos;
};

handlerton *binlog_hton;


/* Check if a given table is opened log table */
int check_if_log_table(uint db_len, const char *db, uint table_name_len,
                       const char *table_name, uint check_if_opened)
{
  return 0;
}

/* log event handlers */

bool Log_to_file_event_handler::
  log_error(enum loglevel level, const char *format,
            va_list args)
{
  return vprint_msg_to_log(level, format, args);
}

void Log_to_file_event_handler::init_pthread_objects()
{
  mysql_log.init_pthread_objects();
  mysql_slow_log.init_pthread_objects();
}


/** Wrapper around MYSQL_LOG::write() for slow log. */

bool Log_to_file_event_handler::
  log_slow(THD *thd, time_t current_time, time_t query_start_arg,
           const char *user_host, uint user_host_len,
           ulonglong query_utime, ulonglong lock_utime, bool is_command,
           const char *sql_text, uint sql_text_len)
{
  return mysql_slow_log.write(thd, current_time, query_start_arg,
                              user_host, user_host_len,
                              query_utime, lock_utime, is_command,
                              sql_text, sql_text_len);
}


/**
   Wrapper around MYSQL_LOG::write() for general log. We need it since we
   want all log event handlers to have the same signature.
*/

bool Log_to_file_event_handler::
  log_general(THD *thd, time_t event_time, const char *user_host,
              uint user_host_len, int thread_id,
              const char *command_type, uint command_type_len,
              const char *sql_text, uint sql_text_len,
              CHARSET_INFO *client_cs)
{
  return mysql_log.write(event_time, user_host, user_host_len,
                         thread_id, command_type, command_type_len,
                         sql_text, sql_text_len);
}


bool Log_to_file_event_handler::init()
{
  if (!is_initialized)
  {
    if (opt_slow_log)
      mysql_slow_log.open_slow_log(sys_var_slow_log_path.value);

    if (opt_log)
      mysql_log.open_query_log(sys_var_general_log_path.value);

    is_initialized= TRUE;
  }

  return FALSE;
}


void Log_to_file_event_handler::cleanup()
{
  mysql_log.cleanup();
  mysql_slow_log.cleanup();
}

void Log_to_file_event_handler::flush()
{
  /* reopen log files */
  if (opt_log)
    mysql_log.reopen_file();
  if (opt_slow_log)
    mysql_slow_log.reopen_file();
}

/*
  Log error with all enabled log event handlers

  SYNOPSIS
    error_log_print()

    level             The level of the error significance: NOTE,
                      WARNING or ERROR.
    format            format string for the error message
    args              list of arguments for the format string

  RETURN
    FALSE - OK
    TRUE - error occured
*/

bool LOGGER::error_log_print(enum loglevel level, const char *format,
                             va_list args)
{
  bool error= FALSE;
  Log_event_handler **current_handler;

  /* currently we don't need locking here as there is no error_log table */
  for (current_handler= error_log_handler_list ; *current_handler ;)
    error= (*current_handler++)->log_error(level, format, args) || error;

  return error;
}


void LOGGER::cleanup_base()
{
  DBUG_ASSERT(inited == 1);
  rwlock_destroy(&LOCK_logger);
  if (file_log_handler)
    file_log_handler->cleanup();
}


void LOGGER::cleanup_end()
{
  DBUG_ASSERT(inited == 1);
  if (file_log_handler)
    delete file_log_handler;
}


/**
  Perform basic log initialization: create file-based log handler and
  init error log.
*/
void LOGGER::init_base()
{
  DBUG_ASSERT(inited == 0);
  inited= 1;

  /*
    Here we create file log handler. We don't do it for the table log handler
    here as it cannot be created so early. The reason is THD initialization,
    which depends on the system variables (parsed later).
  */
  if (!file_log_handler)
    file_log_handler= new Log_to_file_event_handler;

  /* by default we use traditional error log */
  init_error_log(LOG_FILE);

  file_log_handler->init_pthread_objects();
  my_rwlock_init(&LOCK_logger, NULL);
}


bool LOGGER::flush_logs(THD *thd)
{
  int rc= 0;

  /*
    Now we lock logger, as nobody should be able to use logging routines while
    log tables are closed
  */
  logger.lock_exclusive();

  /* reopen log files */
  file_log_handler->flush();

  /* end of log flush */
  logger.unlock();
  return rc;
}


/*
  Log slow query with all enabled log event handlers

  SYNOPSIS
    slow_log_print()

    thd                 THD of the query being logged
    query               The query being logged
    query_length        The length of the query string
    current_utime       Current time in microseconds (from undefined start)

  RETURN
    FALSE   OK
    TRUE    error occured
*/

bool LOGGER::slow_log_print(THD *thd, const char *query, uint query_length,
                            ulonglong current_utime)

{
  bool error= FALSE;
  Log_event_handler **current_handler;
  bool is_command= FALSE;
  char user_host_buff[MAX_USER_HOST_SIZE];
  Security_context *sctx= thd->security_ctx;
  uint user_host_len= 0;
  ulonglong query_utime, lock_utime;

  /*
    Print the message to the buffer if we have slow log enabled
  */

  if (*slow_log_handler_list)
  {
    time_t current_time;

    /* do not log slow queries from replication threads */
    if (thd->slave_thread && !opt_log_slow_slave_statements)
      return 0;

    lock_shared();
    if (!opt_slow_log)
    {
      unlock();
      return 0;
    }

    /* fill in user_host value: the format is "%s[%s] @ %s [%s]" */
    user_host_len= (strxnmov(user_host_buff, MAX_USER_HOST_SIZE,
                             sctx->priv_user ? sctx->priv_user : "", "[",
                             sctx->user ? sctx->user : "", "] @ ",
                             sctx->host ? sctx->host : "", " [",
                             sctx->ip ? sctx->ip : "", "]", NullS) -
                    user_host_buff);

    current_time= my_time_possible_from_micro(current_utime);
    if (thd->start_utime)
    {
      query_utime= (current_utime - thd->start_utime);
      lock_utime=  (thd->utime_after_lock - thd->start_utime);
    }
    else
    {
      query_utime= lock_utime= 0;
    }

    if (!query)
    {
      is_command= TRUE;
      query= command_name[thd->command].str;
      query_length= command_name[thd->command].length;
    }

    for (current_handler= slow_log_handler_list; *current_handler ;)
      error= (*current_handler++)->log_slow(thd, current_time, thd->start_time,
                                            user_host_buff, user_host_len,
                                            query_utime, lock_utime, is_command,
                                            query, query_length) || error;

    unlock();
  }
  return error;
}

bool LOGGER::general_log_write(THD *thd, enum enum_server_command command,
                               const char *query, uint query_length)
{
  bool error= FALSE;
  Log_event_handler **current_handler= general_log_handler_list;
  char user_host_buff[MAX_USER_HOST_SIZE];
  Security_context *sctx= thd->security_ctx;
  ulong id;
  uint user_host_len= 0;
  time_t current_time;

  if (thd)
    id= thd->thread_id;                 /* Normal thread */
  else
    id= 0;                              /* Log from connect handler */

  lock_shared();
  if (!opt_log)
  {
    unlock();
    return 0;
  }
  user_host_len= strxnmov(user_host_buff, MAX_USER_HOST_SIZE,
                          sctx->priv_user ? sctx->priv_user : "", "[",
                          sctx->user ? sctx->user : "", "] @ ",
                          sctx->host ? sctx->host : "", " [",
                          sctx->ip ? sctx->ip : "", "]", NullS) -
                                                          user_host_buff;

  current_time= my_time(0);

  while (*current_handler)
    error|= (*current_handler++)->
      log_general(thd, current_time, user_host_buff,
                  user_host_len, id,
                  command_name[(uint) command].str,
                  command_name[(uint) command].length,
                  query, query_length,
                  thd->variables.character_set_client) || error;
  unlock();

  return error;
}

bool LOGGER::general_log_print(THD *thd, enum enum_server_command command,
                               const char *format, va_list args)
{
  uint message_buff_len= 0;
  char message_buff[MAX_LOG_BUFFER_SIZE];

  /* prepare message */
  if (format)
    message_buff_len= vsnprintf(message_buff, sizeof(message_buff),
                                   format, args);
  else
    message_buff[0]= '\0';

  return general_log_write(thd, command, message_buff, message_buff_len);
}

void LOGGER::init_error_log(uint error_log_printer)
{
  if (error_log_printer & LOG_NONE)
  {
    error_log_handler_list[0]= 0;
    return;
  }

  switch (error_log_printer) {
  case LOG_FILE:
    error_log_handler_list[0]= file_log_handler;
    error_log_handler_list[1]= 0;
    break;
    /* these two are disabled for now */
  case LOG_TABLE:
    DBUG_ASSERT(0);
    break;
  case LOG_TABLE|LOG_FILE:
    DBUG_ASSERT(0);
    break;
  }
}

void LOGGER::init_slow_log(uint slow_log_printer)
{
  if (slow_log_printer & LOG_NONE)
  {
    slow_log_handler_list[0]= 0;
    return;
  }

  slow_log_handler_list[0]= file_log_handler;
  slow_log_handler_list[1]= 0;
}

void LOGGER::init_general_log(uint general_log_printer)
{
  if (general_log_printer & LOG_NONE)
  {
    general_log_handler_list[0]= 0;
    return;
  }

  general_log_handler_list[0]= file_log_handler;
  general_log_handler_list[1]= 0;
}


bool LOGGER::activate_log_handler(THD* thd, uint log_type)
{
  MYSQL_QUERY_LOG *file_log;
  bool res= FALSE;
  lock_exclusive();
  switch (log_type) {
  case QUERY_LOG_SLOW:
    if (!opt_slow_log)
    {
      file_log= file_log_handler->get_mysql_slow_log();

      file_log->open_slow_log(sys_var_slow_log_path.value);
      init_slow_log(log_output_options);
      opt_slow_log= TRUE;
    }
    break;
  case QUERY_LOG_GENERAL:
    if (!opt_log)
    {
      file_log= file_log_handler->get_mysql_log();

      file_log->open_query_log(sys_var_general_log_path.value);
      init_general_log(log_output_options);
      opt_log= TRUE;
    }
    break;
  default:
    DBUG_ASSERT(0);
  }
  unlock();
  return res;
}


void LOGGER::deactivate_log_handler(THD *thd, uint log_type)
{
  my_bool *tmp_opt= 0;
  MYSQL_LOG *file_log;

  switch (log_type) {
  case QUERY_LOG_SLOW:
    tmp_opt= &opt_slow_log;
    file_log= file_log_handler->get_mysql_slow_log();
    break;
  case QUERY_LOG_GENERAL:
    tmp_opt= &opt_log;
    file_log= file_log_handler->get_mysql_log();
    break;
  default:
    assert(0);                                  // Impossible
  }

  if (!(*tmp_opt))
    return;

  lock_exclusive();
  file_log->close(0);
  *tmp_opt= FALSE;
  unlock();
}

int LOGGER::set_handlers(uint error_log_printer,
                         uint slow_log_printer,
                         uint general_log_printer)
{
  /* error log table is not supported yet */
  DBUG_ASSERT(error_log_printer < LOG_TABLE);

  lock_exclusive();

  init_error_log(error_log_printer);
  init_slow_log(slow_log_printer);
  init_general_log(general_log_printer);

  unlock();

  return 0;
}


 /*
  Save position of binary log transaction cache.

  SYNPOSIS
    binlog_trans_log_savepos()

    thd      The thread to take the binlog data from
    pos      Pointer to variable where the position will be stored

  DESCRIPTION

    Save the current position in the binary log transaction cache into
    the variable pointed to by 'pos'
 */

static void
binlog_trans_log_savepos(THD *thd, my_off_t *pos)
{
  DBUG_ENTER("binlog_trans_log_savepos");
  DBUG_ASSERT(pos != NULL);
  if (thd_get_ha_data(thd, binlog_hton) == NULL)
    thd->binlog_setup_trx_data();
  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
  DBUG_ASSERT(mysql_bin_log.is_open());
  *pos= trx_data->position();
  DBUG_PRINT("return", ("*pos: %lu", (ulong) *pos));
  DBUG_VOID_RETURN;
}


/*
  Truncate the binary log transaction cache.

  SYNPOSIS
    binlog_trans_log_truncate()

    thd      The thread to take the binlog data from
    pos      Position to truncate to

  DESCRIPTION

    Truncate the binary log to the given position. Will not change
    anything else.

 */
static void
binlog_trans_log_truncate(THD *thd, my_off_t pos)
{
  DBUG_ENTER("binlog_trans_log_truncate");
  DBUG_PRINT("enter", ("pos: %lu", (ulong) pos));

  DBUG_ASSERT(thd_get_ha_data(thd, binlog_hton) != NULL);
  /* Only true if binlog_trans_log_savepos() wasn't called before */
  DBUG_ASSERT(pos != ~(my_off_t) 0);

  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
  trx_data->truncate(pos);
  DBUG_VOID_RETURN;
}


/*
  this function is mostly a placeholder.
  conceptually, binlog initialization (now mostly done in MYSQL_BIN_LOG::open)
  should be moved here.
*/

int binlog_init(void *p)
{
  binlog_hton= (handlerton *)p;
  binlog_hton->state=opt_bin_log ? SHOW_OPTION_YES : SHOW_OPTION_NO;
  binlog_hton->db_type=DB_TYPE_BINLOG;
  binlog_hton->savepoint_offset= sizeof(my_off_t);
  binlog_hton->close_connection= binlog_close_connection;
  binlog_hton->savepoint_set= binlog_savepoint_set;
  binlog_hton->savepoint_rollback= binlog_savepoint_rollback;
  binlog_hton->commit= binlog_commit;
  binlog_hton->rollback= binlog_rollback;
  binlog_hton->prepare= binlog_prepare;
  binlog_hton->flags= HTON_NOT_USER_SELECTABLE | HTON_HIDDEN;
  return 0;
}

static int binlog_close_connection(handlerton *hton, THD *thd)
{
  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
  DBUG_ASSERT(trx_data->empty());
  thd_set_ha_data(thd, binlog_hton, NULL);
  trx_data->~binlog_trx_data();
  my_free((uchar*)trx_data, MYF(0));
  return 0;
}

/*
  End a transaction.

  SYNOPSIS
    binlog_end_trans()

    thd      The thread whose transaction should be ended
    trx_data Pointer to the transaction data to use
    end_ev   The end event to use, or NULL
    all      True if the entire transaction should be ended, false if
             only the statement transaction should be ended.

  DESCRIPTION

    End the currently open transaction. The transaction can be either
    a real transaction (if 'all' is true) or a statement transaction
    (if 'all' is false).

    If 'end_ev' is NULL, the transaction is a rollback of only
    transactional tables, so the transaction cache will be truncated
    to either just before the last opened statement transaction (if
    'all' is false), or reset completely (if 'all' is true).
 */
static int
binlog_end_trans(THD *thd, binlog_trx_data *trx_data,
                 Log_event *end_ev, bool all)
{
  DBUG_ENTER("binlog_end_trans");
  int error=0;
  IO_CACHE *trans_log= &trx_data->trans_log;
  DBUG_PRINT("enter", ("transaction: %s  end_ev: 0x%lx",
                       all ? "all" : "stmt", (long) end_ev));
  DBUG_PRINT("info", ("thd->options={ %s%s}",
                      FLAGSTR(thd->options, OPTION_NOT_AUTOCOMMIT),
                      FLAGSTR(thd->options, OPTION_BEGIN)));

  /*
    NULL denotes ROLLBACK with nothing to replicate: i.e., rollback of
    only transactional tables.  If the transaction contain changes to
    any non-transactiona tables, we need write the transaction and log
    a ROLLBACK last.
  */
  if (end_ev != NULL)
  {
    /*
      Doing a commit or a rollback including non-transactional tables,
      i.e., ending a transaction where we might write the transaction
      cache to the binary log.

      We can always end the statement when ending a transaction since
      transactions are not allowed inside stored functions.  If they
      were, we would have to ensure that we're not ending a statement
      inside a stored function.
     */
    thd->binlog_flush_pending_rows_event(TRUE);

    error= mysql_bin_log.write(thd, &trx_data->trans_log, end_ev);
    trx_data->reset();

    /*
      We need to step the table map version after writing the
      transaction cache to disk.
    */
    mysql_bin_log.update_table_map_version();
    statistic_increment(binlog_cache_use, &LOCK_status);
    if (trans_log->disk_writes != 0)
    {
      statistic_increment(binlog_cache_disk_use, &LOCK_status);
      trans_log->disk_writes= 0;
    }
  }
  else
  {
    /*
      If rolling back an entire transaction or a single statement not
      inside a transaction, we reset the transaction cache.

      If rolling back a statement in a transaction, we truncate the
      transaction cache to remove the statement.
     */
    if (all || !(thd->options & (OPTION_BEGIN | OPTION_NOT_AUTOCOMMIT)))
    {
      trx_data->reset();

      DBUG_ASSERT(!thd->binlog_get_pending_rows_event());
      thd->clear_binlog_table_maps();
    }
    else                                        // ...statement
      trx_data->truncate(trx_data->before_stmt_pos);

    /*
      We need to step the table map version on a rollback to ensure
      that a new table map event is generated instead of the one that
      was written to the thrown-away transaction cache.
    */
    mysql_bin_log.update_table_map_version();
  }

  DBUG_RETURN(error);
}

static int binlog_prepare(handlerton *hton, THD *thd, bool all)
{
  /*
    do nothing.
    just pretend we can do 2pc, so that MySQL won't
    switch to 1pc.
    real work will be done in MYSQL_BIN_LOG::log_xid()
  */
  return 0;
}

#define YESNO(X) ((X) ? "yes" : "no")

/**
  This function is called once after each statement.

  It has the responsibility to flush the transaction cache to the
  binlog file on commits.

  @param hton  The binlog handlerton.
  @param thd   The client thread that executes the transaction.
  @param all   This is @c true if this is a real transaction commit, and
               @false otherwise.

  @see handlerton::commit
*/
static int binlog_commit(handlerton *hton, THD *thd, bool all)
{
  DBUG_ENTER("binlog_commit");
  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);

  if (trx_data->empty())
  {
    // we're here because trans_log was flushed in MYSQL_BIN_LOG::log_xid()
    trx_data->reset();
    DBUG_RETURN(0);
  }

  /*
    Decision table for committing a transaction. The top part, the
    *conditions* represent different cases that can occur, and hte
    bottom part, the *actions*, represent what should be done in that
    particular case.

    Real transaction        'all' was true

    Statement in cache      There were at least one statement in the
                            transaction cache

    In transaction          We are inside a transaction

    Stmt modified non-trans The statement being committed modified a
                            non-transactional table

    All modified non-trans  Some statement before this one in the
                            transaction modified a non-transactional
                            table


    =============================  = = = = = = = = = = = = = = = =
    Real transaction               N N N N N N N N N N N N N N N N
    Statement in cache             N N N N N N N N Y Y Y Y Y Y Y Y
    In transaction                 N N N N Y Y Y Y N N N N Y Y Y Y
    Stmt modified non-trans        N N Y Y N N Y Y N N Y Y N N Y Y
    All modified non-trans         N Y N Y N Y N Y N Y N Y N Y N Y

    Action: (C)ommit/(A)ccumulate  C C - C A C - C - - - - A A - A
    =============================  = = = = = = = = = = = = = = = =


    =============================  = = = = = = = = = = = = = = = =
    Real transaction               Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y
    Statement in cache             N N N N N N N N Y Y Y Y Y Y Y Y
    In transaction                 N N N N Y Y Y Y N N N N Y Y Y Y
    Stmt modified non-trans        N N Y Y N N Y Y N N Y Y N N Y Y
    All modified non-trans         N Y N Y N Y N Y N Y N Y N Y N Y

    (C)ommit/(A)ccumulate/(-)      - - - - C C - C - - - - C C - C
    =============================  = = = = = = = = = = = = = = = =

    In other words, we commit the transaction if and only if both of
    the following are true:
     - We are not in a transaction and committing a statement

     - We are in a transaction and one (or more) of the following are
       true:

       - A full transaction is committed

         OR

       - A non-transactional statement is committed and there is
         no statement cached

    Otherwise, we accumulate the statement
  */
  ulonglong const in_transaction=
    thd->options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN);
  DBUG_PRINT("debug",
             ("all: %d, empty: %s, in_transaction: %s, all.modified_non_trans_table: %s, stmt.modified_non_trans_table: %s",
              all,
              YESNO(trx_data->empty()),
              YESNO(in_transaction),
              YESNO(thd->transaction.all.modified_non_trans_table),
              YESNO(thd->transaction.stmt.modified_non_trans_table)));
  if ((in_transaction && (all || (!trx_data->at_least_one_stmt && thd->transaction.stmt.modified_non_trans_table))) || (!in_transaction && !all))
  {
    Query_log_event qev(thd, STRING_WITH_LEN("COMMIT"), TRUE, FALSE);
    qev.error_code= 0; // see comment in MYSQL_LOG::write(THD, IO_CACHE)
    int error= binlog_end_trans(thd, trx_data, &qev, all);
    DBUG_RETURN(error);
  }
  DBUG_RETURN(0);
}

/**
  This function is called when a transaction involving a transactional
  table is rolled back.

  It has the responsibility to flush the transaction cache to the
  binlog file. However, if the transaction does not involve
  non-transactional tables, nothing needs to be logged.

  @param hton  The binlog handlerton.
  @param thd   The client thread that executes the transaction.
  @param all   This is @c true if this is a real transaction rollback, and
               @false otherwise.

  @see handlerton::rollback
*/
static int binlog_rollback(handlerton *hton, THD *thd, bool all)
{
  DBUG_ENTER("binlog_rollback");
  int error=0;
  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);

  if (trx_data->empty()) {
    trx_data->reset();
    DBUG_RETURN(0);
  }

  DBUG_PRINT("debug", ("all: %s, all.modified_non_trans_table: %s, stmt.modified_non_trans_table: %s",
                       YESNO(all),
                       YESNO(thd->transaction.all.modified_non_trans_table),
                       YESNO(thd->transaction.stmt.modified_non_trans_table)));
  if ((all && thd->transaction.all.modified_non_trans_table) ||
      (!all && thd->transaction.stmt.modified_non_trans_table) ||
      (thd->options & OPTION_KEEP_LOG))
  {
    /*
      We write the transaction cache with a rollback last if we have
      modified any non-transactional table. We do this even if we are
      committing a single statement that has modified a
      non-transactional table since it can have modified a
      transactional table in that statement as well, which needs to be
      rolled back on the slave.
    */
    Query_log_event qev(thd, STRING_WITH_LEN("ROLLBACK"), TRUE, FALSE);
    qev.error_code= 0; // see comment in MYSQL_LOG::write(THD, IO_CACHE)
    error= binlog_end_trans(thd, trx_data, &qev, all);
  }
  else if ((all && !thd->transaction.all.modified_non_trans_table) ||
           (!all && !thd->transaction.stmt.modified_non_trans_table))
  {
    /*
      If we have modified only transactional tables, we can truncate
      the transaction cache without writing anything to the binary
      log.
     */
    error= binlog_end_trans(thd, trx_data, 0, all);
  }
  DBUG_RETURN(error);
}

/**
  @note
  How do we handle this (unlikely but legal) case:
  @verbatim
    [transaction] + [update to non-trans table] + [rollback to savepoint] ?
  @endverbatim
  The problem occurs when a savepoint is before the update to the
  non-transactional table. Then when there's a rollback to the savepoint, if we
  simply truncate the binlog cache, we lose the part of the binlog cache where
  the update is. If we want to not lose it, we need to write the SAVEPOINT
  command and the ROLLBACK TO SAVEPOINT command to the binlog cache. The latter
  is easy: it's just write at the end of the binlog cache, but the former
  should be *inserted* to the place where the user called SAVEPOINT. The
  solution is that when the user calls SAVEPOINT, we write it to the binlog
  cache (so no need to later insert it). As transactions are never intermixed
  in the binary log (i.e. they are serialized), we won't have conflicts with
  savepoint names when using mysqlbinlog or in the slave SQL thread.
  Then when ROLLBACK TO SAVEPOINT is called, if we updated some
  non-transactional table, we don't truncate the binlog cache but instead write
  ROLLBACK TO SAVEPOINT to it; otherwise we truncate the binlog cache (which
  will chop the SAVEPOINT command from the binlog cache, which is good as in
  that case there is no need to have it in the binlog).
*/

static int binlog_savepoint_set(handlerton *hton, THD *thd, void *sv)
{
  DBUG_ENTER("binlog_savepoint_set");

  binlog_trans_log_savepos(thd, (my_off_t*) sv);
  /* Write it to the binary log */
  
  int const error=
    thd->binlog_query(THD::STMT_QUERY_TYPE,
                      thd->query, thd->query_length, TRUE, FALSE);
  DBUG_RETURN(error);
}

static int binlog_savepoint_rollback(handlerton *hton, THD *thd, void *sv)
{
  DBUG_ENTER("binlog_savepoint_rollback");

  /*
    Write ROLLBACK TO SAVEPOINT to the binlog cache if we have updated some
    non-transactional table. Otherwise, truncate the binlog cache starting
    from the SAVEPOINT command.
  */
  if (unlikely(thd->transaction.all.modified_non_trans_table || 
               (thd->options & OPTION_KEEP_LOG)))
  {
    int error=
      thd->binlog_query(THD::STMT_QUERY_TYPE,
                        thd->query, thd->query_length, TRUE, FALSE);
    DBUG_RETURN(error);
  }
  binlog_trans_log_truncate(thd, *(my_off_t*)sv);
  DBUG_RETURN(0);
}


int check_binlog_magic(IO_CACHE* log, const char** errmsg)
{
  char magic[4];
  DBUG_ASSERT(my_b_tell(log) == 0);

  if (my_b_read(log, (uchar*) magic, sizeof(magic)))
  {
    *errmsg = "I/O error reading the header from the binary log";
    sql_print_error("%s, errno=%d, io cache code=%d", *errmsg, my_errno,
		    log->error);
    return 1;
  }
  if (memcmp(magic, BINLOG_MAGIC, sizeof(magic)))
  {
    *errmsg = "Binlog has bad magic number;  It's not a binary log file that can be used by this version of MySQL";
    return 1;
  }
  return 0;
}


File open_binlog(IO_CACHE *log, const char *log_file_name, const char **errmsg)
{
  File file;
  DBUG_ENTER("open_binlog");

  if ((file = my_open(log_file_name, O_RDONLY | O_BINARY | O_SHARE, 
                      MYF(MY_WME))) < 0)
  {
    sql_print_error("Failed to open log (file '%s', errno %d)",
                    log_file_name, my_errno);
    *errmsg = "Could not open log file";
    goto err;
  }
  if (init_io_cache(log, file, IO_SIZE*2, READ_CACHE, 0, 0,
                    MYF(MY_WME|MY_DONT_CHECK_FILESIZE)))
  {
    sql_print_error("Failed to create a cache on log (file '%s')",
                    log_file_name);
    *errmsg = "Could not open log file";
    goto err;
  }
  if (check_binlog_magic(log,errmsg))
    goto err;
  DBUG_RETURN(file);

err:
  if (file >= 0)
  {
    my_close(file,MYF(0));
    end_io_cache(log);
  }
  DBUG_RETURN(-1);
}


/**
  Find a unique filename for 'filename.#'.

  Set '#' to a number as low as possible.

  @return
    nonzero if not possible to get unique filename
*/

static int find_uniq_filename(char *name)
{
  long                  number;
  uint                  i;
  char                  buff[FN_REFLEN];
  struct st_my_dir     *dir_info;
  register struct fileinfo *file_info;
  ulong                 max_found=0;
  size_t		buf_length, length;
  char			*start, *end;
  DBUG_ENTER("find_uniq_filename");

  length= dirname_part(buff, name, &buf_length);
  start=  name + length;
  end=    strend(start);

  *end='.';
  length= (size_t) (end-start+1);

  if (!(dir_info = my_dir(buff,MYF(MY_DONT_SORT))))
  {						// This shouldn't happen
    strmov(end,".1");				// use name+1
    DBUG_RETURN(0);
  }
  file_info= dir_info->dir_entry;
  for (i=dir_info->number_off_files ; i-- ; file_info++)
  {
    if (bcmp((uchar*) file_info->name, (uchar*) start, length) == 0 &&
	test_if_number(file_info->name+length, &number,0))
    {
      set_if_bigger(max_found,(ulong) number);
    }
  }
  my_dirend(dir_info);

  *end++='.';
  sprintf(end,"%06ld",max_found+1);
  DBUG_RETURN(0);
}


void MYSQL_LOG::init(enum_log_type log_type_arg,
                     enum cache_type io_cache_type_arg)
{
  DBUG_ENTER("MYSQL_LOG::init");
  log_type= log_type_arg;
  io_cache_type= io_cache_type_arg;
  DBUG_PRINT("info",("log_type: %d", log_type));
  DBUG_VOID_RETURN;
}


/*
  Open a (new) log file.

  SYNOPSIS
    open()

    log_name            The name of the log to open
    log_type_arg        The type of the log. E.g. LOG_NORMAL
    new_name            The new name for the logfile. This is only needed
                        when the method is used to open the binlog file.
    io_cache_type_arg   The type of the IO_CACHE to use for this log file

  DESCRIPTION
    Open the logfile, init IO_CACHE and write startup messages
    (in case of general and slow query logs).

  RETURN VALUES
    0   ok
    1   error
*/

bool MYSQL_LOG::open(const char *log_name, enum_log_type log_type_arg,
                     const char *new_name, enum cache_type io_cache_type_arg)
{
  char buff[FN_REFLEN];
  File file= -1;
  int open_flags= O_CREAT | O_BINARY;
  DBUG_ENTER("MYSQL_LOG::open");
  DBUG_PRINT("enter", ("log_type: %d", (int) log_type_arg));

  write_error= 0;

  init(log_type_arg, io_cache_type_arg);

  if (!(name= my_strdup(log_name, MYF(MY_WME))))
  {
    name= (char *)log_name; // for the error message
    goto err;
  }

  if (new_name)
    strmov(log_file_name, new_name);
  else if (generate_new_name(log_file_name, name))
    goto err;

  if (io_cache_type == SEQ_READ_APPEND)
    open_flags |= O_RDWR | O_APPEND;
  else
    open_flags |= O_WRONLY | (log_type == LOG_BIN ? 0 : O_APPEND);

  db[0]= 0;

  if ((file= my_open(log_file_name, open_flags,
                     MYF(MY_WME | ME_WAITTANG))) < 0 ||
      init_io_cache(&log_file, file, IO_SIZE, io_cache_type,
                    my_tell(file, MYF(MY_WME)), 0,
                    MYF(MY_WME | MY_NABP |
                        ((log_type == LOG_BIN) ? MY_WAIT_IF_FULL : 0))))
    goto err;

  if (log_type == LOG_NORMAL)
  {
    char *end;
    int len=snprintf(buff, sizeof(buff), "%s, Version: %s (%s). "
		     "started with:\nTCP Port: %d, Named Pipe: %s\n",
                     my_progname, server_version, MYSQL_COMPILATION_COMMENT,
                     mysqld_port, ""
                     );
    end= strnmov(buff + len, "Time                 Id Command    Argument\n",
                 sizeof(buff) - len);
    if (my_b_write(&log_file, (uchar*) buff, (uint) (end-buff)) ||
	flush_io_cache(&log_file))
      goto err;
  }

  log_state= LOG_OPENED;
  DBUG_RETURN(0);

err:
  sql_print_error("Could not use %s for logging (error %d). \
Turning logging off for the whole duration of the MySQL server process. \
To turn it on again: fix the cause, \
shutdown the MySQL server and restart it.", name, errno);
  if (file >= 0)
    my_close(file, MYF(0));
  end_io_cache(&log_file);
  safeFree(name);
  log_state= LOG_CLOSED;
  DBUG_RETURN(1);
}

MYSQL_LOG::MYSQL_LOG()
  : name(0), write_error(FALSE), inited(FALSE), log_type(LOG_UNKNOWN),
    log_state(LOG_CLOSED)
{
  /*
    We don't want to initialize LOCK_Log here as such initialization depends on
    safe_mutex (when using safe_mutex) which depends on MY_INIT(), which is
    called only in main(). Doing initialization here would make it happen
    before main().
  */
  bzero((char*) &log_file, sizeof(log_file));
}

void MYSQL_LOG::init_pthread_objects()
{
  DBUG_ASSERT(inited == 0);
  inited= 1;
  (void) pthread_mutex_init(&LOCK_log, MY_MUTEX_INIT_SLOW);
}

/*
  Close the log file

  SYNOPSIS
    close()
    exiting     Bitmask. For the slow and general logs the only used bit is
                LOG_CLOSE_TO_BE_OPENED. This is used if we intend to call
                open at once after close.

  NOTES
    One can do an open on the object at once after doing a close.
    The internal structures are not freed until cleanup() is called
*/

void MYSQL_LOG::close(uint exiting)
{					// One can't set log_type here!
  DBUG_ENTER("MYSQL_LOG::close");
  DBUG_PRINT("enter",("exiting: %d", (int) exiting));
  if (log_state == LOG_OPENED)
  {
    end_io_cache(&log_file);

    if (my_sync(log_file.file, MYF(MY_WME)) && ! write_error)
    {
      write_error= 1;
      sql_print_error(ER(ER_ERROR_ON_WRITE), name, errno);
    }

    if (my_close(log_file.file, MYF(MY_WME)) && ! write_error)
    {
      write_error= 1;
      sql_print_error(ER(ER_ERROR_ON_WRITE), name, errno);
    }
  }

  log_state= (exiting & LOG_CLOSE_TO_BE_OPENED) ? LOG_TO_BE_OPENED : LOG_CLOSED;
  safeFree(name);
  DBUG_VOID_RETURN;
}

/** This is called only once. */

void MYSQL_LOG::cleanup()
{
  DBUG_ENTER("cleanup");
  if (inited)
  {
    inited= 0;
    (void) pthread_mutex_destroy(&LOCK_log);
    close(0);
  }
  DBUG_VOID_RETURN;
}


int MYSQL_LOG::generate_new_name(char *new_name, const char *log_name)
{
  fn_format(new_name, log_name, mysql_data_home, "", 4);
  if (log_type == LOG_BIN)
  {
    if (!fn_ext(log_name)[0])
    {
      if (find_uniq_filename(new_name))
      {
	sql_print_error(ER(ER_NO_UNIQUE_LOGFILE), log_name);
	return 1;
      }
    }
  }
  return 0;
}


/*
  Reopen the log file

  SYNOPSIS
    reopen_file()

  DESCRIPTION
    Reopen the log file. The method is used during FLUSH LOGS
    and locks LOCK_log mutex
*/


void MYSQL_QUERY_LOG::reopen_file()
{
  char *save_name;

  DBUG_ENTER("MYSQL_LOG::reopen_file");
  if (!is_open())
  {
    DBUG_PRINT("info",("log is closed"));
    DBUG_VOID_RETURN;
  }

  pthread_mutex_lock(&LOCK_log);

  save_name= name;
  name= 0;				// Don't free name
  close(LOG_CLOSE_TO_BE_OPENED);

  /*
     Note that at this point, log_state != LOG_CLOSED (important for is_open()).
  */

  open(save_name, log_type, 0, io_cache_type);
  my_free(save_name, MYF(0));

  pthread_mutex_unlock(&LOCK_log);

  DBUG_VOID_RETURN;
}


/*
  Write a command to traditional general log file

  SYNOPSIS
    write()

    event_time        command start timestamp
    user_host         the pointer to the string with user@host info
    user_host_len     length of the user_host string. this is computed once
                      and passed to all general log  event handlers
    thread_id         Id of the thread, issued a query
    command_type      the type of the command being logged
    command_type_len  the length of the string above
    sql_text          the very text of the query being executed
    sql_text_len      the length of sql_text string

  DESCRIPTION

   Log given command to to normal (not rotable) log file

  RETURN
    FASE - OK
    TRUE - error occured
*/

bool MYSQL_QUERY_LOG::write(time_t event_time, const char *user_host,
                            uint user_host_len, int thread_id,
                            const char *command_type, uint command_type_len,
                            const char *sql_text, uint sql_text_len)
{
  char buff[32];
  uint length= 0;
  char local_time_buff[MAX_TIME_SIZE];
  struct tm start;
  uint time_buff_len= 0;

  (void) pthread_mutex_lock(&LOCK_log);

  /* Test if someone closed between the is_open test and lock */
  if (is_open())
  {
    /* Note that my_b_write() assumes it knows the length for this */
      if (event_time != last_time)
      {
        last_time= event_time;

        localtime_r(&event_time, &start);

        time_buff_len= snprintf(local_time_buff, MAX_TIME_SIZE,
                                "%02d%02d%02d %2d:%02d:%02d",
                                start.tm_year % 100, start.tm_mon + 1,
                                start.tm_mday, start.tm_hour,
                                start.tm_min, start.tm_sec);

        if (my_b_write(&log_file, (uchar*) local_time_buff, time_buff_len))
          goto err;
      }
      else
        if (my_b_write(&log_file, (uchar*) "\t\t" ,2) < 0)
          goto err;

      /* command_type, thread_id */
      length= snprintf(buff, 32, "%5ld ", (long) thread_id);

    if (my_b_write(&log_file, (uchar*) buff, length))
      goto err;

    if (my_b_write(&log_file, (uchar*) command_type, command_type_len))
      goto err;

    if (my_b_write(&log_file, (uchar*) "\t", 1))
      goto err;

    /* sql_text */
    if (my_b_write(&log_file, (uchar*) sql_text, sql_text_len))
      goto err;

    if (my_b_write(&log_file, (uchar*) "\n", 1) ||
        flush_io_cache(&log_file))
      goto err;
  }

  (void) pthread_mutex_unlock(&LOCK_log);
  return FALSE;
err:

  if (!write_error)
  {
    write_error= 1;
    sql_print_error(ER(ER_ERROR_ON_WRITE), name, errno);
  }
  (void) pthread_mutex_unlock(&LOCK_log);
  return TRUE;
}


/*
  Log a query to the traditional slow log file

  SYNOPSIS
    write()

    thd               THD of the query
    current_time      current timestamp
    query_start_arg   command start timestamp
    user_host         the pointer to the string with user@host info
    user_host_len     length of the user_host string. this is computed once
                      and passed to all general log event handlers
    query_utime       Amount of time the query took to execute (in microseconds)
    lock_utime        Amount of time the query was locked (in microseconds)
    is_command        The flag, which determines, whether the sql_text is a
                      query or an administrator command.
    sql_text          the very text of the query or administrator command
                      processed
    sql_text_len      the length of sql_text string

  DESCRIPTION

   Log a query to the slow log file.

  RETURN
    FALSE - OK
    TRUE - error occured
*/

bool MYSQL_QUERY_LOG::write(THD *thd, time_t current_time,
                            time_t query_start_arg, const char *user_host,
                            uint user_host_len, ulonglong query_utime,
                            ulonglong lock_utime, bool is_command,
                            const char *sql_text, uint sql_text_len)
{
  bool error= 0;
  DBUG_ENTER("MYSQL_QUERY_LOG::write");

  (void) pthread_mutex_lock(&LOCK_log);

  if (!is_open())
  {
    (void) pthread_mutex_unlock(&LOCK_log);
    DBUG_RETURN(0);
  }

  if (is_open())
  {						// Safety agains reopen
    int tmp_errno= 0;
    char buff[80], *end;
    char query_time_buff[22+7], lock_time_buff[22+7];
    uint buff_len;
    end= buff;

    if (!(specialflag & SPECIAL_SHORT_LOG_FORMAT))
    {
      if (current_time != last_time)
      {
        last_time= current_time;
        struct tm start;
        localtime_r(&current_time, &start);

        buff_len= snprintf(buff, sizeof buff,
                           "# Time: %02d%02d%02d %2d:%02d:%02d\n",
                           start.tm_year % 100, start.tm_mon + 1,
                           start.tm_mday, start.tm_hour,
                           start.tm_min, start.tm_sec);

        /* Note that my_b_write() assumes it knows the length for this */
        if (my_b_write(&log_file, (uchar*) buff, buff_len))
          tmp_errno= errno;
      }
      const uchar uh[]= "# User@Host: ";
      if (my_b_write(&log_file, uh, sizeof(uh) - 1))
        tmp_errno= errno;
      if (my_b_write(&log_file, (uchar*) user_host, user_host_len))
        tmp_errno= errno;
      if (my_b_write(&log_file, (uchar*) "\n", 1))
        tmp_errno= errno;
    }
    /* For slow query log */
    sprintf(query_time_buff, "%.6f", ulonglong2double(query_utime)/1000000.0);
    sprintf(lock_time_buff,  "%.6f", ulonglong2double(lock_utime)/1000000.0);
    if (my_b_printf(&log_file,
                    "# Query_time: %s  Lock_time: %s"
                    " Rows_sent: %lu  Rows_examined: %lu\n",
                    query_time_buff, lock_time_buff,
                    (ulong) thd->sent_row_count,
                    (ulong) thd->examined_row_count) == (uint) -1)
      tmp_errno= errno;
    if (thd->db && strcmp(thd->db, db))
    {						// Database changed
      if (my_b_printf(&log_file,"use %s;\n",thd->db) == (uint) -1)
        tmp_errno= errno;
      strmov(db,thd->db);
    }
    if (thd->stmt_depends_on_first_successful_insert_id_in_prev_stmt)
    {
      end=strmov(end, ",last_insert_id=");
      end=longlong10_to_str((longlong)
                            thd->first_successful_insert_id_in_prev_stmt_for_binlog,
                            end, -10);
    }
    // Save value if we do an insert.
    if (thd->auto_inc_intervals_in_cur_stmt_for_binlog.nb_elements() > 0)
    {
      if (!(specialflag & SPECIAL_SHORT_LOG_FORMAT))
      {
        end=strmov(end,",insert_id=");
        end=longlong10_to_str((longlong)
                              thd->auto_inc_intervals_in_cur_stmt_for_binlog.minimum(),
                              end, -10);
      }
    }

    /*
      This info used to show up randomly, depending on whether the query
      checked the query start time or not. now we always write current
      timestamp to the slow log
    */
    end= strmov(end, ",timestamp=");
    end= int10_to_str((long) current_time, end, 10);

    if (end != buff)
    {
      *end++=';';
      *end='\n';
      if (my_b_write(&log_file, (uchar*) "SET ", 4) ||
          my_b_write(&log_file, (uchar*) buff + 1, (uint) (end-buff)))
        tmp_errno= errno;
    }
    if (is_command)
    {
      end= strxmov(buff, "# administrator command: ", NullS);
      buff_len= (ulong) (end - buff);
      my_b_write(&log_file, (uchar*) buff, buff_len);
    }
    if (my_b_write(&log_file, (uchar*) sql_text, sql_text_len) ||
        my_b_write(&log_file, (uchar*) ";\n",2) ||
        flush_io_cache(&log_file))
      tmp_errno= errno;
    if (tmp_errno)
    {
      error= 1;
      if (! write_error)
      {
        write_error= 1;
        sql_print_error(ER(ER_ERROR_ON_WRITE), name, error);
      }
    }
  }
  (void) pthread_mutex_unlock(&LOCK_log);
  DBUG_RETURN(error);
}


/**
  @todo
  The following should be using fn_format();  We just need to
  first change fn_format() to cut the file name if it's too long.
*/
const char *MYSQL_LOG::generate_name(const char *log_name,
                                      const char *suffix,
                                      bool strip_ext, char *buff)
{
  if (!log_name || !log_name[0])
  {
    strmake(buff, pidfile_name, FN_REFLEN - strlen(suffix) - 1);
    return (const char *)
      fn_format(buff, buff, "", suffix, MYF(MY_REPLACE_EXT|MY_REPLACE_DIR));
  }
  // get rid of extension if the log is binary to avoid problems
  if (strip_ext)
  {
    char *p= fn_ext(log_name);
    uint length= (uint) (p - log_name);
    strmake(buff, log_name, min(length, FN_REFLEN));
    return (const char*)buff;
  }
  return log_name;
}



MYSQL_BIN_LOG::MYSQL_BIN_LOG()
  :bytes_written(0), prepared_xids(0), file_id(1), open_count(1),
   need_start_event(TRUE), m_table_map_version(0),
   description_event_for_exec(0), description_event_for_queue(0)
{
  /*
    We don't want to initialize locks here as such initialization depends on
    safe_mutex (when using safe_mutex) which depends on MY_INIT(), which is
    called only in main(). Doing initialization here would make it happen
    before main().
  */
  index_file_name[0] = 0;
  bzero((char*) &index_file, sizeof(index_file));
}

/* this is called only once */

void MYSQL_BIN_LOG::cleanup()
{
  DBUG_ENTER("cleanup");
  if (inited)
  {
    inited= 0;
    close(LOG_CLOSE_INDEX|LOG_CLOSE_STOP_EVENT);
    delete description_event_for_queue;
    delete description_event_for_exec;
    (void) pthread_mutex_destroy(&LOCK_log);
    (void) pthread_mutex_destroy(&LOCK_index);
    (void) pthread_cond_destroy(&update_cond);
  }
  DBUG_VOID_RETURN;
}


/* Init binlog-specific vars */
void MYSQL_BIN_LOG::init(bool no_auto_events_arg, ulong max_size_arg)
{
  DBUG_ENTER("MYSQL_BIN_LOG::init");
  no_auto_events= no_auto_events_arg;
  max_size= max_size_arg;
  DBUG_PRINT("info",("max_size: %lu", max_size));
  DBUG_VOID_RETURN;
}


void MYSQL_BIN_LOG::init_pthread_objects()
{
  DBUG_ASSERT(inited == 0);
  inited= 1;
  (void) pthread_mutex_init(&LOCK_log, MY_MUTEX_INIT_SLOW);
  (void) pthread_mutex_init(&LOCK_index, MY_MUTEX_INIT_SLOW);
  (void) pthread_cond_init(&update_cond, 0);
}


bool MYSQL_BIN_LOG::open_index_file(const char *index_file_name_arg,
                                const char *log_name)
{
  File index_file_nr= -1;
  DBUG_ASSERT(!my_b_inited(&index_file));

  /*
    First open of this class instance
    Create an index file that will hold all file names uses for logging.
    Add new entries to the end of it.
  */
  myf opt= MY_UNPACK_FILENAME;
  if (!index_file_name_arg)
  {
    index_file_name_arg= log_name;    // Use same basename for index file
    opt= MY_UNPACK_FILENAME | MY_REPLACE_EXT;
  }
  fn_format(index_file_name, index_file_name_arg, mysql_data_home,
            ".index", opt);
  if ((index_file_nr= my_open(index_file_name,
                              O_RDWR | O_CREAT | O_BINARY ,
                              MYF(MY_WME))) < 0 ||
       my_sync(index_file_nr, MYF(MY_WME)) ||
       init_io_cache(&index_file, index_file_nr,
                     IO_SIZE, WRITE_CACHE,
                     my_seek(index_file_nr,0L,MY_SEEK_END,MYF(0)),
			0, MYF(MY_WME | MY_WAIT_IF_FULL)))
  {
    /*
      TODO: all operations creating/deleting the index file or a log, should
      call my_sync_dir() or my_sync_dir_by_file() to be durable.
      TODO: file creation should be done with my_create() not my_open().
    */
    if (index_file_nr >= 0)
      my_close(index_file_nr,MYF(0));
    return TRUE;
  }
  return FALSE;
}


/**
  Open a (new) binlog file.

  - Open the log file and the index file. Register the new
  file name in it
  - When calling this when the file is in use, you must have a locks
  on LOCK_log and LOCK_index.

  @retval
    0	ok
  @retval
    1	error
*/

bool MYSQL_BIN_LOG::open(const char *log_name,
                         enum_log_type log_type_arg,
                         const char *new_name,
                         enum cache_type io_cache_type_arg,
                         bool no_auto_events_arg,
                         ulong max_size_arg,
                         bool null_created_arg)
{
  File file= -1;
  DBUG_ENTER("MYSQL_BIN_LOG::open");
  DBUG_PRINT("enter",("log_type: %d",(int) log_type_arg));

  write_error=0;

  /* open the main log file */
  if (MYSQL_LOG::open(log_name, log_type_arg, new_name, io_cache_type_arg))
    DBUG_RETURN(1);                            /* all warnings issued */

  init(no_auto_events_arg, max_size_arg);

  open_count++;

  DBUG_ASSERT(log_type == LOG_BIN);

  {
    bool write_file_name_to_index_file=0;

    if (!my_b_filelength(&log_file))
    {
      /*
	The binary log file was empty (probably newly created)
	This is the normal case and happens when the user doesn't specify
	an extension for the binary log files.
	In this case we write a standard header to it.
      */
      if (my_b_safe_write(&log_file, (uchar*) BINLOG_MAGIC,
			  BIN_LOG_HEADER_SIZE))
        goto err;
      bytes_written+= BIN_LOG_HEADER_SIZE;
      write_file_name_to_index_file= 1;
    }

    DBUG_ASSERT(my_b_inited(&index_file) != 0);
    reinit_io_cache(&index_file, WRITE_CACHE,
                    my_b_filelength(&index_file), 0, 0);
    if (need_start_event && !no_auto_events)
    {
      /*
        In 4.x we set need_start_event=0 here, but in 5.0 we want a Start event
        even if this is not the very first binlog.
      */
      Format_description_log_event s(BINLOG_VERSION);
      /*
        don't set LOG_EVENT_BINLOG_IN_USE_F for SEQ_READ_APPEND io_cache
        as we won't be able to reset it later
      */
      if (io_cache_type == WRITE_CACHE)
        s.flags|= LOG_EVENT_BINLOG_IN_USE_F;
      if (!s.is_valid())
        goto err;
      s.dont_set_created= null_created_arg;
      if (s.write(&log_file))
        goto err;
      bytes_written+= s.data_written;
    }
    if (description_event_for_queue &&
        description_event_for_queue->binlog_version>=4)
    {
      /*
        This is a relay log written to by the I/O slave thread.
        Write the event so that others can later know the format of this relay
        log.
        Note that this event is very close to the original event from the
        master (it has binlog version of the master, event types of the
        master), so this is suitable to parse the next relay log's event. It
        has been produced by
        Format_description_log_event::Format_description_log_event(char* buf,).
        Why don't we want to write the description_event_for_queue if this
        event is for format<4 (3.23 or 4.x): this is because in that case, the
        description_event_for_queue describes the data received from the
        master, but not the data written to the relay log (*conversion*),
        which is in format 4 (slave's).
      */
      /*
        Set 'created' to 0, so that in next relay logs this event does not
        trigger cleaning actions on the slave in
        Format_description_log_event::apply_event_impl().
      */
      description_event_for_queue->created= 0;
      /* Don't set log_pos in event header */
      description_event_for_queue->artificial_event=1;

      if (description_event_for_queue->write(&log_file))
        goto err;
      bytes_written+= description_event_for_queue->data_written;
    }
    if (flush_io_cache(&log_file) ||
        my_sync(log_file.file, MYF(MY_WME)))
      goto err;

    if (write_file_name_to_index_file)
    {
      /*
        As this is a new log file, we write the file name to the index
        file. As every time we write to the index file, we sync it.
      */
      if (my_b_write(&index_file, (uchar*) log_file_name,
		     strlen(log_file_name)) ||
	  my_b_write(&index_file, (uchar*) "\n", 1) ||
	  flush_io_cache(&index_file) ||
          my_sync(index_file.file, MYF(MY_WME)))
	goto err;
    }
  }
  log_state= LOG_OPENED;

  DBUG_RETURN(0);

err:
  sql_print_error("Could not use %s for logging (error %d). \
Turning logging off for the whole duration of the MySQL server process. \
To turn it on again: fix the cause, \
shutdown the MySQL server and restart it.", name, errno);
  if (file >= 0)
    my_close(file,MYF(0));
  end_io_cache(&log_file);
  end_io_cache(&index_file);
  safeFree(name);
  log_state= LOG_CLOSED;
  DBUG_RETURN(1);
}


int MYSQL_BIN_LOG::get_current_log(LOG_INFO* linfo)
{
  pthread_mutex_lock(&LOCK_log);
  int ret = raw_get_current_log(linfo);
  pthread_mutex_unlock(&LOCK_log);
  return ret;
}

int MYSQL_BIN_LOG::raw_get_current_log(LOG_INFO* linfo)
{
  strmake(linfo->log_file_name, log_file_name, sizeof(linfo->log_file_name)-1);
  linfo->pos = my_b_tell(&log_file);
  return 0;
}

/**
  Move all data up in a file in an filename index file.

    We do the copy outside of the IO_CACHE as the cache buffers would just
    make things slower and more complicated.
    In most cases the copy loop should only do one read.

  @param index_file			File to move
  @param offset			Move everything from here to beginning

  @note
    File will be truncated to be 'offset' shorter or filled up with newlines

  @retval
    0	ok
*/

#ifdef HAVE_REPLICATION

static bool copy_up_file_and_fill(IO_CACHE *index_file, my_off_t offset)
{
  int bytes_read;
  my_off_t init_offset= offset;
  File file= index_file->file;
  uchar io_buf[IO_SIZE*2];
  DBUG_ENTER("copy_up_file_and_fill");

  for (;; offset+= bytes_read)
  {
    (void) my_seek(file, offset, MY_SEEK_SET, MYF(0));
    if ((bytes_read= (int) my_read(file, io_buf, sizeof(io_buf), MYF(MY_WME)))
	< 0)
      goto err;
    if (!bytes_read)
      break;					// end of file
    (void) my_seek(file, offset-init_offset, MY_SEEK_SET, MYF(0));
    if (my_write(file, io_buf, bytes_read, MYF(MY_WME | MY_NABP)))
      goto err;
  }
  /* The following will either truncate the file or fill the end with \n' */
  if (ftruncate(file, offset - init_offset) || my_sync(file, MYF(MY_WME)))
    goto err;

  /* Reset data in old index cache */
  reinit_io_cache(index_file, READ_CACHE, (my_off_t) 0, 0, 1);
  DBUG_RETURN(0);

err:
  DBUG_RETURN(1);
}

#endif /* HAVE_REPLICATION */

/**
  Find the position in the log-index-file for the given log name.

  @param linfo		Store here the found log file name and position to
                       the NEXT log file name in the index file.
  @param log_name	Filename to find in the index file.
                       Is a null pointer if we want to read the first entry
  @param need_lock	Set this to 1 if the parent doesn't already have a
                       lock on LOCK_index

  @note
    On systems without the truncate function the file will end with one or
    more empty lines.  These will be ignored when reading the file.

  @retval
    0			ok
  @retval
    LOG_INFO_EOF	        End of log-index-file found
  @retval
    LOG_INFO_IO		Got IO error while reading file
*/

int MYSQL_BIN_LOG::find_log_pos(LOG_INFO *linfo, const char *log_name,
			    bool need_lock)
{
  int error= 0;
  char *fname= linfo->log_file_name;
  uint log_name_len= log_name ? (uint) strlen(log_name) : 0;
  DBUG_ENTER("find_log_pos");
  DBUG_PRINT("enter",("log_name: %s", log_name ? log_name : "NULL"));

  /*
    Mutex needed because we need to make sure the file pointer does not
    move from under our feet
  */
  if (need_lock)
    pthread_mutex_lock(&LOCK_index);
  safe_mutex_assert_owner(&LOCK_index);

  /* As the file is flushed, we can't get an error here */
  (void) reinit_io_cache(&index_file, READ_CACHE, (my_off_t) 0, 0, 0);

  for (;;)
  {
    uint length;
    my_off_t offset= my_b_tell(&index_file);
    /* If we get 0 or 1 characters, this is the end of the file */

    if ((length= my_b_gets(&index_file, fname, FN_REFLEN)) <= 1)
    {
      /* Did not find the given entry; Return not found or error */
      error= !index_file.error ? LOG_INFO_EOF : LOG_INFO_IO;
      break;
    }

    // if the log entry matches, null string matching anything
    if (!log_name ||
	(log_name_len == length-1 && fname[log_name_len] == '\n' &&
	 !memcmp(fname, log_name, log_name_len)))
    {
      DBUG_PRINT("info",("Found log file entry"));
      fname[length-1]=0;			// remove last \n
      linfo->index_file_start_offset= offset;
      linfo->index_file_offset = my_b_tell(&index_file);
      break;
    }
  }

  if (need_lock)
    pthread_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}


/**
  Find the position in the log-index-file for the given log name.

  @param
    linfo		Store here the next log file name and position to
			the file name after that.
  @param
    need_lock		Set this to 1 if the parent doesn't already have a
			lock on LOCK_index

  @note
    - Before calling this function, one has to call find_log_pos()
    to set up 'linfo'
    - Mutex needed because we need to make sure the file pointer does not move
    from under our feet

  @retval
    0			ok
  @retval
    LOG_INFO_EOF	        End of log-index-file found
  @retval
    LOG_INFO_IO		Got IO error while reading file
*/

int MYSQL_BIN_LOG::find_next_log(LOG_INFO* linfo, bool need_lock)
{
  int error= 0;
  uint length;
  char *fname= linfo->log_file_name;

  if (need_lock)
    pthread_mutex_lock(&LOCK_index);
  safe_mutex_assert_owner(&LOCK_index);

  /* As the file is flushed, we can't get an error here */
  (void) reinit_io_cache(&index_file, READ_CACHE, linfo->index_file_offset, 0,
			 0);

  linfo->index_file_start_offset= linfo->index_file_offset;
  if ((length=my_b_gets(&index_file, fname, FN_REFLEN)) <= 1)
  {
    error = !index_file.error ? LOG_INFO_EOF : LOG_INFO_IO;
    goto err;
  }
  fname[length-1]=0;				// kill \n
  linfo->index_file_offset = my_b_tell(&index_file);

err:
  if (need_lock)
    pthread_mutex_unlock(&LOCK_index);
  return error;
}


/**
  Delete all logs refered to in the index file.
  Start writing to a new log file.

  The new index file will only contain this file.

  @param thd		Thread

  @note
    If not called from slave thread, write start event to new log

  @retval
    0	ok
  @retval
    1   error
*/

bool MYSQL_BIN_LOG::reset_logs(THD* thd)
{
  LOG_INFO linfo;
  bool error=0;
  const char* save_name;
  DBUG_ENTER("reset_logs");

  ha_reset_logs(thd);
  /*
    We need to get both locks to be sure that no one is trying to
    write to the index log file.
  */
  pthread_mutex_lock(&LOCK_log);
  pthread_mutex_lock(&LOCK_index);

  /*
    The following mutex is needed to ensure that no threads call
    'delete thd' as we would then risk missing a 'rollback' from this
    thread. If the transaction involved MyISAM tables, it should go
    into binlog even on rollback.
  */
  VOID(pthread_mutex_lock(&LOCK_thread_count));

  /* Save variables so that we can reopen the log */
  save_name=name;
  name=0;					// Protect against free
  close(LOG_CLOSE_TO_BE_OPENED);

  /* First delete all old log files */

  if (find_log_pos(&linfo, NullS, 0))
  {
    error=1;
    goto err;
  }

  for (;;)
  {
    if ((error= my_delete_allow_opened(linfo.log_file_name, MYF(0))) != 0)
    {
      if (my_errno == ENOENT) 
      {
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                            linfo.log_file_name);
        sql_print_information("Failed to delete file '%s'",
                              linfo.log_file_name);
        my_errno= 0;
        error= 0;
      }
      else
      {
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                            ER_BINLOG_PURGE_FATAL_ERR,
                            "a problem with deleting %s; "
                            "consider examining correspondence "
                            "of your binlog index file "
                            "to the actual binlog files",
                            linfo.log_file_name);
        error= 1;
        goto err;
      }
    }
    if (find_next_log(&linfo, 0))
      break;
  }

  /* Start logging with a new file */
  close(LOG_CLOSE_INDEX);
  if ((error= my_delete_allow_opened(index_file_name, MYF(0))))	// Reset (open will update)
  {
    if (my_errno == ENOENT) 
    {
      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                          ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                          index_file_name);
      sql_print_information("Failed to delete file '%s'",
                            index_file_name);
      my_errno= 0;
      error= 0;
    }
    else
    {
      push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                          ER_BINLOG_PURGE_FATAL_ERR,
                          "a problem with deleting %s; "
                          "consider examining correspondence "
                          "of your binlog index file "
                          "to the actual binlog files",
                          index_file_name);
      error= 1;
      goto err;
    }
  }
  if (!thd->slave_thread)
    need_start_event=1;
  if (!open_index_file(index_file_name, 0))
    open(save_name, log_type, 0, io_cache_type, no_auto_events, max_size, 0);
  my_free((uchar*) save_name, MYF(0));

err:
  VOID(pthread_mutex_unlock(&LOCK_thread_count));
  pthread_mutex_unlock(&LOCK_index);
  pthread_mutex_unlock(&LOCK_log);
  DBUG_RETURN(error);
}


/**
  Delete relay log files prior to rli->group_relay_log_name
  (i.e. all logs which are not involved in a non-finished group
  (transaction)), remove them from the index file and start on next
  relay log.

  IMPLEMENTATION
  - Protects index file with LOCK_index
  - Delete relevant relay log files
  - Copy all file names after these ones to the front of the index file
  - If the OS has truncate, truncate the file, else fill it with \n'
  - Read the next file name from the index file and store in rli->linfo

  @param rli	       Relay log information
  @param included     If false, all relay logs that are strictly before
                      rli->group_relay_log_name are deleted ; if true, the
                      latter is deleted too (i.e. all relay logs
                      read by the SQL slave thread are deleted).

  @note
    - This is only called from the slave-execute thread when it has read
    all commands from a relay log and want to switch to a new relay log.
    - When this happens, we can be in an active transaction as
    a transaction can span over two relay logs
    (although it is always written as a single block to the master's binary
    log, hence cannot span over two master's binary logs).

  @retval
    0			ok
  @retval
    LOG_INFO_EOF	        End of log-index-file found
  @retval
    LOG_INFO_SEEK	Could not allocate IO cache
  @retval
    LOG_INFO_IO		Got IO error while reading file
*/

#ifdef HAVE_REPLICATION

int MYSQL_BIN_LOG::purge_first_log(Relay_log_info* rli, bool included)
{
  int error;
  DBUG_ENTER("purge_first_log");

  DBUG_ASSERT(is_open());
  DBUG_ASSERT(rli->slave_running == 1);
  DBUG_ASSERT(!strcmp(rli->linfo.log_file_name,rli->event_relay_log_name));

  pthread_mutex_lock(&LOCK_index);
  pthread_mutex_lock(&rli->log_space_lock);
  rli->relay_log.purge_logs(rli->group_relay_log_name, included,
                            0, 0, &rli->log_space_total);
  // Tell the I/O thread to take the relay_log_space_limit into account
  rli->ignore_log_space_limit= 0;
  pthread_mutex_unlock(&rli->log_space_lock);

  /*
    Ok to broadcast after the critical region as there is no risk of
    the mutex being destroyed by this thread later - this helps save
    context switches
  */
  pthread_cond_broadcast(&rli->log_space_cond);
  
  /*
    Read the next log file name from the index file and pass it back to
    the caller
    If included is true, we want the first relay log;
    otherwise we want the one after event_relay_log_name.
  */
  if ((included && (error=find_log_pos(&rli->linfo, NullS, 0))) ||
      (!included &&
       ((error=find_log_pos(&rli->linfo, rli->event_relay_log_name, 0)) ||
        (error=find_next_log(&rli->linfo, 0)))))
  {
    char buff[22];
    sql_print_error("next log error: %d  offset: %s  log: %s included: %d",
                    error,
                    llstr(rli->linfo.index_file_offset,buff),
                    rli->group_relay_log_name,
                    included);
    goto err;
  }

  /*
    Reset rli's coordinates to the current log.
  */
  rli->event_relay_log_pos= BIN_LOG_HEADER_SIZE;
  strmake(rli->event_relay_log_name,rli->linfo.log_file_name,
	  sizeof(rli->event_relay_log_name)-1);

  /*
    If we removed the rli->group_relay_log_name file,
    we must update the rli->group* coordinates, otherwise do not touch it as the
    group's execution is not finished (e.g. COMMIT not executed)
  */
  if (included)
  {
    rli->group_relay_log_pos = BIN_LOG_HEADER_SIZE;
    strmake(rli->group_relay_log_name,rli->linfo.log_file_name,
            sizeof(rli->group_relay_log_name)-1);
    rli->notify_group_relay_log_name_update();
  }

  /* Store where we are in the new file for the execution thread */
  flush_relay_log_info(rli);

err:
  pthread_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}

/**
  Update log index_file.
*/

int MYSQL_BIN_LOG::update_log_index(LOG_INFO* log_info, bool need_update_threads)
{
  if (copy_up_file_and_fill(&index_file, log_info->index_file_start_offset))
    return LOG_INFO_IO;

  // now update offsets in index file for running threads
  if (need_update_threads)
    adjust_linfo_offsets(log_info->index_file_start_offset);
  return 0;
}

/**
  Remove all logs before the given log from disk and from the index file.

  @param to_log	      Delete all log file name before this file.
  @param included            If true, to_log is deleted too.
  @param need_mutex
  @param need_update_threads If we want to update the log coordinates of
                             all threads. False for relay logs, true otherwise.
  @param freed_log_space     If not null, decrement this variable of
                             the amount of log space freed

  @note
    If any of the logs before the deleted one is in use,
    only purge logs up to this one.

  @retval
    0			ok
  @retval
    LOG_INFO_EOF		to_log not found
    LOG_INFO_EMFILE             too many files opened
    LOG_INFO_FATAL              if any other than ENOENT error from
                                stat() or my_delete()
*/

int MYSQL_BIN_LOG::purge_logs(const char *to_log, 
                          bool included,
                          bool need_mutex, 
                          bool need_update_threads, 
                          ulonglong *decrease_log_space)
{
  int error;
  int ret = 0;
  bool exit_loop= 0;
  LOG_INFO log_info;
  DBUG_ENTER("purge_logs");
  DBUG_PRINT("info",("to_log= %s",to_log));

  if (need_mutex)
    pthread_mutex_lock(&LOCK_index);
  if ((error=find_log_pos(&log_info, to_log, 0 /*no mutex*/)))
    goto err;

  /*
    File name exists in index file; delete until we find this file
    or a file that is used.
  */
  if ((error=find_log_pos(&log_info, NullS, 0 /*no mutex*/)))
    goto err;
  while ((strcmp(to_log,log_info.log_file_name) || (exit_loop=included)) &&
         !log_in_use(log_info.log_file_name))
  {
    struct stat s;
    if (stat(log_info.log_file_name, &s))
    {
      if (errno == ENOENT) 
      {
        /*
          It's not fatal if we can't stat a log file that does not exist;
          If we could not stat, we won't delete.
        */     
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                            log_info.log_file_name);
        sql_print_information("Failed to execute stat on file '%s'",
			      log_info.log_file_name);
        my_errno= 0;
      }
      else
      {
        /*
          Other than ENOENT are fatal
        */
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                            ER_BINLOG_PURGE_FATAL_ERR,
                            "a problem with getting info on being purged %s; "
                            "consider examining correspondence "
                            "of your binlog index file "
                            "to the actual binlog files",
                            log_info.log_file_name);
        error= LOG_INFO_FATAL;
        goto err;
      }
    }
    else
    {
      DBUG_PRINT("info",("purging %s",log_info.log_file_name));
      if (!my_delete(log_info.log_file_name, MYF(0)))
      {
        if (decrease_log_space)
          *decrease_log_space-= s.st_size;
      }
      else
      {
        if (my_errno == ENOENT) 
        {
          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                              ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                              log_info.log_file_name);
          sql_print_information("Failed to delete file '%s'",
                                log_info.log_file_name);
          my_errno= 0;
        }
        else
        {
          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                              ER_BINLOG_PURGE_FATAL_ERR,
                              "a problem with deleting %s; "
                              "consider examining correspondence "
                              "of your binlog index file "
                              "to the actual binlog files",
                              log_info.log_file_name);
          if (my_errno == EMFILE)
          {
            DBUG_PRINT("info",
                       ("my_errno: %d, set ret = LOG_INFO_EMFILE", my_errno));
            error= LOG_INFO_EMFILE;
          }
          error= LOG_INFO_FATAL;
          goto err;
        }
      }
    }

    ha_binlog_index_purge_file(current_thd, log_info.log_file_name);

    if (find_next_log(&log_info, 0) || exit_loop)
      break;
  }
  
  /*
    If we get killed -9 here, the sysadmin would have to edit
    the log index file after restart - otherwise, this should be safe
  */
  error= update_log_index(&log_info, need_update_threads);
  if (error == 0) {
    error = ret;
  }

err:
  if (need_mutex)
    pthread_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}

/**
  Remove all logs before the given file date from disk and from the
  index file.

  @param thd		Thread pointer
  @param before_date	Delete all log files before given date.

  @note
    If any of the logs before the deleted one is in use,
    only purge logs up to this one.

  @retval
    0				ok
  @retval
    LOG_INFO_PURGE_NO_ROTATE	Binary file that can't be rotated
    LOG_INFO_FATAL              if any other than ENOENT error from
                                stat() or my_delete()
*/

int MYSQL_BIN_LOG::purge_logs_before_date(time_t purge_time)
{
  int error;
  LOG_INFO log_info;
  struct stat stat_area;

  DBUG_ENTER("purge_logs_before_date");

  pthread_mutex_lock(&LOCK_index);

  /*
    Delete until we find curren file
    or a file that is used or a file
    that is older than purge_time.
  */
  if ((error=find_log_pos(&log_info, NullS, 0 /*no mutex*/)))
    goto err;

  while (strcmp(log_file_name, log_info.log_file_name) &&
	 !log_in_use(log_info.log_file_name))
  {
    if (stat(log_info.log_file_name, &stat_area))
    {
      if (errno == ENOENT) 
      {
        /*
          It's not fatal if we can't stat a log file that does not exist.
        */     
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                            log_info.log_file_name);
	sql_print_information("Failed to execute stat on file '%s'",
			      log_info.log_file_name);
        my_errno= 0;
      }
      else
      {
        /*
          Other than ENOENT are fatal
        */
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                            ER_BINLOG_PURGE_FATAL_ERR,
                            "a problem with getting info on being purged %s; "
                            "consider examining correspondence "
                            "of your binlog index file "
                            "to the actual binlog files",
                            log_info.log_file_name);
        error= LOG_INFO_FATAL;
        goto err;
      }
    }
    else
    {
      if (stat_area.st_mtime >= purge_time)
        break;
      if (my_delete(log_info.log_file_name, MYF(0)))
      {
        if (my_errno == ENOENT) 
        {
          /* It's not fatal even if we can't delete a log file */
          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                              ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                              log_info.log_file_name);
          sql_print_information("Failed to delete file '%s'",
                                log_info.log_file_name);
          my_errno= 0;
        }
        else
        {
          push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_ERROR,
                              ER_BINLOG_PURGE_FATAL_ERR,
                              "a problem with deleting %s; "
                              "consider examining correspondence "
                              "of your binlog index file "
                              "to the actual binlog files",
                              log_info.log_file_name);
          error= LOG_INFO_FATAL;
          goto err;
        }
      }
      ha_binlog_index_purge_file(current_thd, log_info.log_file_name);
    }
    if (find_next_log(&log_info, 0))
      break;
  }

  /*
    If we get killed -9 here, the sysadmin would have to edit
    the log index file after restart - otherwise, this should be safe
  */
  error= update_log_index(&log_info, 1);

err:
  pthread_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}
#endif /* HAVE_REPLICATION */


/**
  Create a new log file name.

  @param buf		buf of at least FN_REFLEN where new name is stored

  @note
    If file name will be longer then FN_REFLEN it will be truncated
*/

void MYSQL_BIN_LOG::make_log_name(char* buf, const char* log_ident)
{
  uint dir_len = dirname_length(log_file_name); 
  if (dir_len >= FN_REFLEN)
    dir_len=FN_REFLEN-1;
  strnmov(buf, log_file_name, dir_len);
  strmake(buf+dir_len, log_ident, FN_REFLEN - dir_len -1);
}


/**
  Check if we are writing/reading to the given log file.
*/

bool MYSQL_BIN_LOG::is_active(const char *log_file_name_arg)
{
  return !strcmp(log_file_name, log_file_name_arg);
}


/*
  Wrappers around new_file_impl to avoid using argument
  to control locking. The argument 1) less readable 2) breaks
  incapsulation 3) allows external access to the class without
  a lock (which is not possible with private new_file_without_locking
  method).
*/

void MYSQL_BIN_LOG::new_file()
{
  new_file_impl(1);
}


void MYSQL_BIN_LOG::new_file_without_locking()
{
  new_file_impl(0);
}


/**
  Start writing to a new log file or reopen the old file.

  @param need_lock		Set to 1 if caller has not locked LOCK_log

  @note
    The new file name is stored last in the index file
*/

void MYSQL_BIN_LOG::new_file_impl(bool need_lock)
{
  char new_name[FN_REFLEN], *new_name_ptr, *old_name;

  DBUG_ENTER("MYSQL_BIN_LOG::new_file_impl");
  if (!is_open())
  {
    DBUG_PRINT("info",("log is closed"));
    DBUG_VOID_RETURN;
  }

  if (need_lock)
    pthread_mutex_lock(&LOCK_log);
  pthread_mutex_lock(&LOCK_index);

  safe_mutex_assert_owner(&LOCK_log);
  safe_mutex_assert_owner(&LOCK_index);

  /*
    if binlog is used as tc log, be sure all xids are "unlogged",
    so that on recover we only need to scan one - latest - binlog file
    for prepared xids. As this is expected to be a rare event,
    simple wait strategy is enough. We're locking LOCK_log to be sure no
    new Xid_log_event's are added to the log (and prepared_xids is not
    increased), and waiting on COND_prep_xids for late threads to
    catch up.
  */
  if (prepared_xids)
  {
    tc_log_page_waits++;
    pthread_mutex_lock(&LOCK_prep_xids);
    while (prepared_xids) {
      DBUG_PRINT("info", ("prepared_xids=%lu", prepared_xids));
      pthread_cond_wait(&COND_prep_xids, &LOCK_prep_xids);
    }
    pthread_mutex_unlock(&LOCK_prep_xids);
  }

  /* Reuse old name if not binlog and not update log */
  new_name_ptr= name;

  /*
    If user hasn't specified an extension, generate a new log name
    We have to do this here and not in open as we want to store the
    new file name in the current binary log file.
  */
  if (generate_new_name(new_name, name))
    goto end;
  new_name_ptr=new_name;

  if (log_type == LOG_BIN)
  {
    if (!no_auto_events)
    {
      /*
        We log the whole file name for log file as the user may decide
        to change base names at some point.
      */
      Rotate_log_event r(new_name+dirname_length(new_name),
                         0, LOG_EVENT_OFFSET, 0);
      r.write(&log_file);
      bytes_written += r.data_written;
    }
    /*
      Update needs to be signalled even if there is no rotate event
      log rotation should give the waiting thread a signal to
      discover EOF and move on to the next log.
    */
    signal_update();
  }
  old_name=name;
  name=0;				// Don't free name
  close(LOG_CLOSE_TO_BE_OPENED);

  /*
     Note that at this point, log_state != LOG_CLOSED (important for is_open()).
  */

  /*
     new_file() is only used for rotation (in FLUSH LOGS or because size >
     max_binlog_size or max_relay_log_size).
     If this is a binary log, the Format_description_log_event at the beginning of
     the new file should have created=0 (to distinguish with the
     Format_description_log_event written at server startup, which should
     trigger temp tables deletion on slaves.
  */

  open(old_name, log_type, new_name_ptr,
       io_cache_type, no_auto_events, max_size, 1);
  my_free(old_name,MYF(0));

end:
  if (need_lock)
    pthread_mutex_unlock(&LOCK_log);
  pthread_mutex_unlock(&LOCK_index);

  DBUG_VOID_RETURN;
}


bool MYSQL_BIN_LOG::append(Log_event* ev)
{
  bool error = 0;
  pthread_mutex_lock(&LOCK_log);
  DBUG_ENTER("MYSQL_BIN_LOG::append");

  DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);
  /*
    Log_event::write() is smart enough to use my_b_write() or
    my_b_append() depending on the kind of cache we have.
  */
  if (ev->write(&log_file))
  {
    error=1;
    goto err;
  }
  bytes_written+= ev->data_written;
  DBUG_PRINT("info",("max_size: %lu",max_size));
  if ((uint) my_b_append_tell(&log_file) > max_size)
    new_file_without_locking();

err:
  pthread_mutex_unlock(&LOCK_log);
  signal_update();				// Safe as we don't call close
  DBUG_RETURN(error);
}


bool MYSQL_BIN_LOG::appendv(const char* buf, uint len,...)
{
  bool error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::appendv");
  va_list(args);
  va_start(args,len);

  DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);

  safe_mutex_assert_owner(&LOCK_log);
  do
  {
    if (my_b_append(&log_file,(uchar*) buf,len))
    {
      error= 1;
      goto err;
    }
    bytes_written += len;
  } while ((buf=va_arg(args,const char*)) && (len=va_arg(args,uint)));
  DBUG_PRINT("info",("max_size: %lu",max_size));
  if ((uint) my_b_append_tell(&log_file) > max_size)
    new_file_without_locking();

err:
  if (!error)
    signal_update();
  DBUG_RETURN(error);
}


bool MYSQL_BIN_LOG::flush_and_sync()
{
  int err=0, fd=log_file.file;
  safe_mutex_assert_owner(&LOCK_log);
  if (flush_io_cache(&log_file))
    return 1;
  if (++sync_binlog_counter >= sync_binlog_period && sync_binlog_period)
  {
    sync_binlog_counter= 0;
    err=my_sync(fd, MYF(MY_WME));
  }
  return err;
}

void MYSQL_BIN_LOG::start_union_events(THD *thd, query_id_t query_id_param)
{
  DBUG_ASSERT(!thd->binlog_evt_union.do_union);
  thd->binlog_evt_union.do_union= TRUE;
  thd->binlog_evt_union.unioned_events= FALSE;
  thd->binlog_evt_union.unioned_events_trans= FALSE;
  thd->binlog_evt_union.first_query_id= query_id_param;
}

void MYSQL_BIN_LOG::stop_union_events(THD *thd)
{
  DBUG_ASSERT(thd->binlog_evt_union.do_union);
  thd->binlog_evt_union.do_union= FALSE;
}

bool MYSQL_BIN_LOG::is_query_in_union(THD *thd, query_id_t query_id_param)
{
  return (thd->binlog_evt_union.do_union && 
          query_id_param >= thd->binlog_evt_union.first_query_id);
}


/*
  These functions are placed in this file since they need access to
  binlog_hton, which has internal linkage.
*/

int THD::binlog_setup_trx_data()
{
  DBUG_ENTER("THD::binlog_setup_trx_data");
  binlog_trx_data *trx_data=
    (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);

  if (trx_data)
    DBUG_RETURN(0);                             // Already set up

  trx_data= (binlog_trx_data*) my_malloc(sizeof(binlog_trx_data), MYF(MY_ZEROFILL));
  if (!trx_data ||
      open_cached_file(&trx_data->trans_log, mysql_tmpdir,
                       LOG_PREFIX, binlog_cache_size, MYF(MY_WME)))
  {
    my_free((uchar*)trx_data, MYF(MY_ALLOW_ZERO_PTR));
    DBUG_RETURN(1);                      // Didn't manage to set it up
  }
  thd_set_ha_data(this, binlog_hton, trx_data);

  trx_data= new (thd_get_ha_data(this, binlog_hton)) binlog_trx_data;

  DBUG_RETURN(0);
}

/*
  Function to start a statement and optionally a transaction for the
  binary log.

  SYNOPSIS
    binlog_start_trans_and_stmt()

  DESCRIPTION

    This function does three things:
    - Start a transaction if not in autocommit mode or if a BEGIN
      statement has been seen.

    - Start a statement transaction to allow us to truncate the binary
      log.

    - Save the currrent binlog position so that we can roll back the
      statement by truncating the transaction log.

      We only update the saved position if the old one was undefined,
      the reason is that there are some cases (e.g., for CREATE-SELECT)
      where the position is saved twice (e.g., both in
      select_create::prepare() and THD::binlog_write_table_map()) , but
      we should use the first. This means that calls to this function
      can be used to start the statement before the first table map
      event, to include some extra events.
 */

void
THD::binlog_start_trans_and_stmt()
{
  binlog_trx_data *trx_data= (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);
  DBUG_ENTER("binlog_start_trans_and_stmt");
  DBUG_PRINT("enter", ("trx_data: 0x%lx  trx_data->before_stmt_pos: %lu",
                       (long) trx_data,
                       (trx_data ? (ulong) trx_data->before_stmt_pos :
                        (ulong) 0)));

  if (trx_data == NULL ||
      trx_data->before_stmt_pos == MY_OFF_T_UNDEF)
  {
    this->binlog_set_stmt_begin();
    if (options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN))
      trans_register_ha(this, TRUE, binlog_hton);
    trans_register_ha(this, FALSE, binlog_hton);
    /*
      Mark statement transaction as read/write. We never start
      a binary log transaction and keep it read-only,
      therefore it's best to mark the transaction read/write just
      at the same time we start it.
      Not necessary to mark the normal transaction read/write
      since the statement-level flag will be propagated automatically
      inside ha_commit_trans.
    */
    ha_data[binlog_hton->slot].ha_info[0].set_trx_read_write();
  }
  DBUG_VOID_RETURN;
}

void THD::binlog_set_stmt_begin() {
  binlog_trx_data *trx_data=
    (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);

  /*
    The call to binlog_trans_log_savepos() might create the trx_data
    structure, if it didn't exist before, so we save the position
    into an auto variable and then write it into the transaction
    data for the binary log (i.e., trx_data).
  */
  my_off_t pos= 0;
  binlog_trans_log_savepos(this, &pos);
  trx_data= (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);
  trx_data->before_stmt_pos= pos;
}


/*
  Write a table map to the binary log.
 */

int THD::binlog_write_table_map(TABLE *table, bool is_trans)
{
  int error;
  DBUG_ENTER("THD::binlog_write_table_map");
  DBUG_PRINT("enter", ("table: 0x%lx  (%s: #%lu)",
                       (long) table, table->s->table_name.str,
                       table->s->table_map_id));

  /* Pre-conditions */
  DBUG_ASSERT(current_stmt_binlog_row_based && mysql_bin_log.is_open());
  DBUG_ASSERT(table->s->table_map_id != ULONG_MAX);

  Table_map_log_event::flag_set const
    flags= Table_map_log_event::TM_NO_FLAGS;

  Table_map_log_event
    the_event(this, table, table->s->table_map_id, is_trans, flags);

  if (is_trans && binlog_table_maps == 0)
    binlog_start_trans_and_stmt();

  if ((error= mysql_bin_log.write(&the_event)))
    DBUG_RETURN(error);

  binlog_table_maps++;
  table->s->table_map_version= mysql_bin_log.table_map_version();
  DBUG_RETURN(0);
}

Rows_log_event*
THD::binlog_get_pending_rows_event() const
{
  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);
  /*
    This is less than ideal, but here's the story: If there is no
    trx_data, prepare_pending_rows_event() has never been called
    (since the trx_data is set up there). In that case, we just return
    NULL.
   */
  return trx_data ? trx_data->pending() : NULL;
}

void
THD::binlog_set_pending_rows_event(Rows_log_event* ev)
{
  if (thd_get_ha_data(this, binlog_hton) == NULL)
    binlog_setup_trx_data();

  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(this, binlog_hton);

  DBUG_ASSERT(trx_data);
  trx_data->set_pending(ev);
}


/*
  Moves the last bunch of rows from the pending Rows event to the binlog
  (either cached binlog if transaction, or disk binlog). Sets a new pending
  event.
*/
int
MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
                                                Rows_log_event* event)
{
  DBUG_ENTER("MYSQL_BIN_LOG::flush_and_set_pending_rows_event(event)");
  DBUG_ASSERT(mysql_bin_log.is_open());
  DBUG_PRINT("enter", ("event: 0x%lx", (long) event));

  int error= 0;

  binlog_trx_data *const trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);

  DBUG_ASSERT(trx_data);

  DBUG_PRINT("info", ("trx_data->pending(): 0x%lx", (long) trx_data->pending()));

  if (Rows_log_event* pending= trx_data->pending())
  {
    IO_CACHE *file= &log_file;

    /*
      Decide if we should write to the log file directly or to the
      transaction log.
    */
    if (pending->get_cache_stmt() || my_b_tell(&trx_data->trans_log))
      file= &trx_data->trans_log;

    /*
      If we are writing to the log file directly, we could avoid
      locking the log. This does not work since we need to step the
      m_table_map_version below, and that change has to be protected
      by the LOCK_log mutex.
    */
    pthread_mutex_lock(&LOCK_log);

    /*
      Write pending event to log file or transaction cache
    */
    if (pending->write(file))
    {
      pthread_mutex_unlock(&LOCK_log);
      DBUG_RETURN(1);
    }

    /*
      We step the table map version if we are writing an event
      representing the end of a statement.  We do this regardless of
      wheather we write to the transaction cache or to directly to the
      file.

      In an ideal world, we could avoid stepping the table map version
      if we were writing to a transaction cache, since we could then
      reuse the table map that was written earlier in the transaction
      cache.  This does not work since STMT_END_F implies closing all
      table mappings on the slave side.

      TODO: Find a solution so that table maps does not have to be
      written several times within a transaction.
     */
    if (pending->get_flags(Rows_log_event::STMT_END_F))
      ++m_table_map_version;

    delete pending;

    if (file == &log_file)
    {
      error= flush_and_sync();
      if (!error)
      {
        signal_update();
        rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED);
      }
    }

    pthread_mutex_unlock(&LOCK_log);
  }

  thd->binlog_set_pending_rows_event(event);

  DBUG_RETURN(error);
}

/**
  Write an event to the binary log.
*/

bool MYSQL_BIN_LOG::write(Log_event *event_info)
{
  THD *thd= event_info->thd;
  bool error= 1;
  DBUG_ENTER("MYSQL_BIN_LOG::write(Log_event *)");

  if (thd->binlog_evt_union.do_union)
  {
    /*
      In Stored function; Remember that function call caused an update.
      We will log the function call to the binary log on function exit
    */
    thd->binlog_evt_union.unioned_events= TRUE;
    thd->binlog_evt_union.unioned_events_trans |= event_info->cache_stmt;
    DBUG_RETURN(0);
  }

  /*
    Flush the pending rows event to the transaction cache or to the
    log file.  Since this function potentially aquire the LOCK_log
    mutex, we do this before aquiring the LOCK_log mutex in this
    function.

    We only end the statement if we are in a top-level statement.  If
    we are inside a stored function, we do not end the statement since
    this will close all tables on the slave.
  */
  bool const end_stmt= false;
  thd->binlog_flush_pending_rows_event(end_stmt);

  pthread_mutex_lock(&LOCK_log);

  /*
     In most cases this is only called if 'is_open()' is true; in fact this is
     mostly called if is_open() *was* true a few instructions before, but it
     could have changed since.
  */
  if (likely(is_open()))
  {
    IO_CACHE *file= &log_file;
    /*
      In the future we need to add to the following if tests like
      "do the involved tables match (to be implemented)
      binlog_[wild_]{do|ignore}_table?" (WL#1049)"
    */
    const char *local_db= event_info->get_db();
    if ((thd && !(thd->options & OPTION_BIN_LOG)) ||
	(!binlog_filter->db_ok(local_db)))
    {
      VOID(pthread_mutex_unlock(&LOCK_log));
      DBUG_RETURN(0);
    }

    /*
      Should we write to the binlog cache or to the binlog on disk?
      Write to the binlog cache if:
      - it is already not empty (meaning we're in a transaction; note that the
     present event could be about a non-transactional table, but still we need
     to write to the binlog cache in that case to handle updates to mixed
     trans/non-trans table types the best possible in binlogging)
      - or if the event asks for it (cache_stmt == TRUE).
    */
    if (opt_using_transactions && thd)
    {
      if (thd->binlog_setup_trx_data())
        goto err;

      binlog_trx_data *const trx_data=
        (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
      IO_CACHE *trans_log= &trx_data->trans_log;
      my_off_t trans_log_pos= my_b_tell(trans_log);
      if (event_info->get_cache_stmt() || trans_log_pos != 0)
      {
        DBUG_PRINT("info", ("Using trans_log: cache: %d, trans_log_pos: %lu",
                            event_info->get_cache_stmt(),
                            (ulong) trans_log_pos));
        if (trans_log_pos == 0)
          thd->binlog_start_trans_and_stmt();
        file= trans_log;
      }
      /*
        TODO as Mats suggested, for all the cases above where we write to
        trans_log, it sounds unnecessary to lock LOCK_log. We should rather
        test first if we want to write to trans_log, and if not, lock
        LOCK_log.
      */
    }
    DBUG_PRINT("info",("event type: %d",event_info->get_type_code()));

    /*
      No check for auto events flag here - this write method should
      never be called if auto-events are enabled
    */

    /*
      1. Write first log events which describe the 'run environment'
      of the SQL command
    */

    /*
      If row-based binlogging, Insert_id, Rand and other kind of "setting
      context" events are not needed.
    */
    if (thd)
    {
      if (!thd->current_stmt_binlog_row_based)
      {
        if (thd->stmt_depends_on_first_successful_insert_id_in_prev_stmt)
        {
          Intvar_log_event e(thd,(uchar) LAST_INSERT_ID_EVENT,
                             thd->first_successful_insert_id_in_prev_stmt_for_binlog);
          if (e.write(file))
            goto err;
        }
        if (thd->auto_inc_intervals_in_cur_stmt_for_binlog.nb_elements() > 0)
        {
          DBUG_PRINT("info",("number of auto_inc intervals: %u",
                             thd->auto_inc_intervals_in_cur_stmt_for_binlog.
                             nb_elements()));
          /*
            If the auto_increment was second in a table's index (possible with
            MyISAM or BDB) (table->next_number_keypart != 0), such event is
            in fact not necessary. We could avoid logging it.
          */
          Intvar_log_event e(thd, (uchar) INSERT_ID_EVENT,
                             thd->auto_inc_intervals_in_cur_stmt_for_binlog.
                             minimum());
          if (e.write(file))
            goto err;
        }
        if (thd->rand_used)
        {
          Rand_log_event e(thd,thd->rand_saved_seed1,thd->rand_saved_seed2);
          if (e.write(file))
            goto err;
        }
        if (thd->user_var_events.elements)
        {
          for (uint i= 0; i < thd->user_var_events.elements; i++)
          {
            BINLOG_USER_VAR_EVENT *user_var_event;
            get_dynamic(&thd->user_var_events,(uchar*) &user_var_event, i);
            User_var_log_event e(thd, user_var_event->user_var_event->name.str,
                                 user_var_event->user_var_event->name.length,
                                 user_var_event->value,
                                 user_var_event->length,
                                 user_var_event->type,
                                 user_var_event->charset_number);
            if (e.write(file))
              goto err;
          }
        }
      }
    }

    /*
       Write the SQL command
     */

    if (event_info->write(file))
      goto err;

    if (file == &log_file) // we are writing to the real log (disk)
    {
      if (flush_and_sync())
	goto err;
      signal_update();
      rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED);
    }
    error=0;

err:
    if (error)
    {
      if (my_errno == EFBIG)
	my_message(ER_TRANS_CACHE_FULL, ER(ER_TRANS_CACHE_FULL), MYF(0));
      else
	my_error(ER_ERROR_ON_WRITE, MYF(0), name, errno);
      write_error=1;
    }
  }

  if (event_info->flags & LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F)
    ++m_table_map_version;

  pthread_mutex_unlock(&LOCK_log);
  DBUG_RETURN(error);
}


int error_log_print(enum loglevel level, const char *format,
                    va_list args)
{
  return logger.error_log_print(level, format, args);
}


bool slow_log_print(THD *thd, const char *query, uint query_length,
                    ulonglong current_utime)
{
  return logger.slow_log_print(thd, query, query_length, current_utime);
}


bool LOGGER::log_command(THD *thd, enum enum_server_command command)
{
  /*
    Log command if we have at least one log event handler enabled and want
    to log this king of commands
  */
  if (*general_log_handler_list && (what_to_log & (1L << (uint) command)))
  {
    if (thd->options & OPTION_LOG_OFF)
    {
      /* No logging */
      return FALSE;
    }

    return TRUE;
  }

  return FALSE;
}


bool general_log_print(THD *thd, enum enum_server_command command,
                       const char *format, ...)
{
  va_list args;
  uint error= 0;

  /* Print the message to the buffer if we want to log this king of commands */
  if (! logger.log_command(thd, command))
    return FALSE;

  va_start(args, format);
  error= logger.general_log_print(thd, command, format, args);
  va_end(args);

  return error;
}

bool general_log_write(THD *thd, enum enum_server_command command,
                       const char *query, uint query_length)
{
  /* Write the message to the log if we want to log this king of commands */
  if (logger.log_command(thd, command))
    return logger.general_log_write(thd, command, query, query_length);

  return FALSE;
}

void MYSQL_BIN_LOG::rotate_and_purge(uint flags)
{
  if (!(flags & RP_LOCK_LOG_IS_ALREADY_LOCKED))
    pthread_mutex_lock(&LOCK_log);
  if ((flags & RP_FORCE_ROTATE) ||
      (my_b_tell(&log_file) >= (my_off_t) max_size))
  {
    new_file_without_locking();
#ifdef HAVE_REPLICATION
    if (expire_logs_days)
    {
      time_t purge_time= my_time(0) - expire_logs_days*24*60*60;
      if (purge_time >= 0)
        purge_logs_before_date(purge_time);
    }
#endif
  }
  if (!(flags & RP_LOCK_LOG_IS_ALREADY_LOCKED))
    pthread_mutex_unlock(&LOCK_log);
}

uint MYSQL_BIN_LOG::next_file_id()
{
  uint res;
  pthread_mutex_lock(&LOCK_log);
  res = file_id++;
  pthread_mutex_unlock(&LOCK_log);
  return res;
}


/*
  Write the contents of a cache to the binary log.

  SYNOPSIS
    write_cache()
    cache    Cache to write to the binary log
    lock_log True if the LOCK_log mutex should be aquired, false otherwise
    sync_log True if the log should be flushed and sync:ed

  DESCRIPTION
    Write the contents of the cache to the binary log. The cache will
    be reset as a READ_CACHE to be able to read the contents from it.
 */

int MYSQL_BIN_LOG::write_cache(IO_CACHE *cache, bool lock_log, bool sync_log)
{
  Mutex_sentry sentry(lock_log ? &LOCK_log : NULL);

  if (reinit_io_cache(cache, READ_CACHE, 0, 0, 0))
    return ER_ERROR_ON_WRITE;
  uint length= my_b_bytes_in_cache(cache), group, carry, hdr_offs;
  long val;
  uchar header[LOG_EVENT_HEADER_LEN];

  /*
    The events in the buffer have incorrect end_log_pos data
    (relative to beginning of group rather than absolute),
    so we'll recalculate them in situ so the binlog is always
    correct, even in the middle of a group. This is possible
    because we now know the start position of the group (the
    offset of this cache in the log, if you will); all we need
    to do is to find all event-headers, and add the position of
    the group to the end_log_pos of each event.  This is pretty
    straight forward, except that we read the cache in segments,
    so an event-header might end up on the cache-border and get
    split.
  */

  group= (uint)my_b_tell(&log_file);
  hdr_offs= carry= 0;

  do
  {

    /*
      if we only got a partial header in the last iteration,
      get the other half now and process a full header.
    */
    if (unlikely(carry > 0))
    {
      DBUG_ASSERT(carry < LOG_EVENT_HEADER_LEN);

      /* assemble both halves */
      memcpy(&header[carry], (char *)cache->read_pos, LOG_EVENT_HEADER_LEN - carry);

      /* fix end_log_pos */
      val= uint4korr(&header[LOG_POS_OFFSET]) + group;
      int4store(&header[LOG_POS_OFFSET], val);

      /* write the first half of the split header */
      if (my_b_write(&log_file, header, carry))
        return ER_ERROR_ON_WRITE;

      /*
        copy fixed second half of header to cache so the correct
        version will be written later.
      */
      memcpy((char *)cache->read_pos, &header[carry], LOG_EVENT_HEADER_LEN - carry);

      /* next event header at ... */
      hdr_offs = uint4korr(&header[EVENT_LEN_OFFSET]) - carry;

      carry= 0;
    }

    /* if there is anything to write, process it. */

    if (likely(length > 0))
    {
      /*
        process all event-headers in this (partial) cache.
        if next header is beyond current read-buffer,
        we'll get it later (though not necessarily in the
        very next iteration, just "eventually").
      */

      while (hdr_offs < length)
      {
        /*
          partial header only? save what we can get, process once
          we get the rest.
        */

        if (hdr_offs + LOG_EVENT_HEADER_LEN > length)
        {
          carry= length - hdr_offs;
          memcpy(header, (char *)cache->read_pos + hdr_offs, carry);
          length= hdr_offs;
        }
        else
        {
          /* we've got a full event-header, and it came in one piece */

          uchar *log_pos= (uchar *)cache->read_pos + hdr_offs + LOG_POS_OFFSET;

          /* fix end_log_pos */
          val= uint4korr(log_pos) + group;
          int4store(log_pos, val);

          /* next event header at ... */
          log_pos= (uchar *)cache->read_pos + hdr_offs + EVENT_LEN_OFFSET;
          hdr_offs += uint4korr(log_pos);

        }
      }

      /*
        Adjust hdr_offs. Note that it may still point beyond the segment
        read in the next iteration; if the current event is very long,
        it may take a couple of read-iterations (and subsequent adjustments
        of hdr_offs) for it to point into the then-current segment.
        If we have a split header (!carry), hdr_offs will be set at the
        beginning of the next iteration, overwriting the value we set here:
      */
      hdr_offs -= length;
    }

    /* Write data to the binary log file */
    if (my_b_write(&log_file, cache->read_pos, length))
      return ER_ERROR_ON_WRITE;
    cache->read_pos=cache->read_end;		// Mark buffer used up
  } while ((length= my_b_fill(cache)));

  DBUG_ASSERT(carry == 0);

  if (sync_log)
    flush_and_sync();

  return 0;                                     // All OK
}

/**
  Write a cached log entry to the binary log.
  - To support transaction over replication, we wrap the transaction
  with BEGIN/COMMIT or BEGIN/ROLLBACK in the binary log.
  We want to write a BEGIN/ROLLBACK block when a non-transactional table
  was updated in a transaction which was rolled back. This is to ensure
  that the same updates are run on the slave.

  @param thd
  @param cache		The cache to copy to the binlog
  @param commit_event   The commit event to print after writing the
                        contents of the cache.

  @note
    We only come here if there is something in the cache.
  @note
    The thing in the cache is always a complete transaction.
  @note
    'cache' needs to be reinitialized after this functions returns.
*/

bool MYSQL_BIN_LOG::write(THD *thd, IO_CACHE *cache, Log_event *commit_event)
{
  DBUG_ENTER("MYSQL_BIN_LOG::write(THD *, IO_CACHE *, Log_event *)");
  VOID(pthread_mutex_lock(&LOCK_log));

  /* NULL would represent nothing to replicate after ROLLBACK */
  DBUG_ASSERT(commit_event != NULL);

  DBUG_ASSERT(is_open());
  if (likely(is_open()))                       // Should always be true
  {
    /*
      We only bother to write to the binary log if there is anything
      to write.
     */
    if (my_b_tell(cache) > 0)
    {
      /*
        Log "BEGIN" at the beginning of every transaction.  Here, a
        transaction is either a BEGIN..COMMIT block or a single
        statement in autocommit mode.
      */
      Query_log_event qinfo(thd, STRING_WITH_LEN("BEGIN"), TRUE, FALSE);
      /*
        Imagine this is rollback due to net timeout, after all
        statements of the transaction succeeded. Then we want a
        zero-error code in BEGIN.  In other words, if there was a
        really serious error code it's already in the statement's
        events, there is no need to put it also in this internally
        generated event, and as this event is generated late it would
        lead to false alarms.

        This is safer than thd->clear_error() against kills at shutdown.
      */
      qinfo.error_code= 0;
      /*
        Now this Query_log_event has artificial log_pos 0. It must be
        adjusted to reflect the real position in the log. Not doing it
        would confuse the slave: it would prevent this one from
        knowing where he is in the master's binlog, which would result
        in wrong positions being shown to the user, MASTER_POS_WAIT
        undue waiting etc.
      */
      if (qinfo.write(&log_file))
        goto err;

      DBUG_EXECUTE_IF("crash_before_writing_xid",
                      {
                        if ((write_error= write_cache(cache, false, true)))
                          DBUG_PRINT("info", ("error writing binlog cache: %d",
                                               write_error));
                        DBUG_PRINT("info", ("crashing before writing xid"));
                        abort();
                      });

      if ((write_error= write_cache(cache, false, false)))
        goto err;

      if (commit_event && commit_event->write(&log_file))
        goto err;
      if (flush_and_sync())
        goto err;
      DBUG_EXECUTE_IF("half_binlogged_transaction", abort(););
      if (cache->error)				// Error on read
      {
        sql_print_error(ER(ER_ERROR_ON_READ), cache->file_name, errno);
        write_error=1;				// Don't give more errors
        goto err;
      }
      signal_update();
    }

    /*
      if commit_event is Xid_log_event, increase the number of
      prepared_xids (it's decreasd in ::unlog()). Binlog cannot be rotated
      if there're prepared xids in it - see the comment in new_file() for
      an explanation.
      If the commit_event is not Xid_log_event (then it's a Query_log_event)
      rotate binlog, if necessary.
    */
    if (commit_event && commit_event->get_type_code() == XID_EVENT)
    {
      pthread_mutex_lock(&LOCK_prep_xids);
      prepared_xids++;
      pthread_mutex_unlock(&LOCK_prep_xids);
    }
    else
      rotate_and_purge(RP_LOCK_LOG_IS_ALREADY_LOCKED);
  }
  VOID(pthread_mutex_unlock(&LOCK_log));

  DBUG_RETURN(0);

err:
  if (!write_error)
  {
    write_error= 1;
    sql_print_error(ER(ER_ERROR_ON_WRITE), name, errno);
  }
  VOID(pthread_mutex_unlock(&LOCK_log));
  DBUG_RETURN(1);
}


/**
  Wait until we get a signal that the relay log has been updated

  @param[in] thd   a THD struct
  @note
    LOCK_log must be taken before calling this function.
    It will be released at the end of the function.
*/

void MYSQL_BIN_LOG::wait_for_update_relay_log(THD* thd)
{
  const char *old_msg;
  DBUG_ENTER("wait_for_update_relay_log");
  old_msg= thd->enter_cond(&update_cond, &LOCK_log,
                           "Slave has read all relay log; " 
                           "waiting for the slave I/O "
                           "thread to update it" );
  pthread_cond_wait(&update_cond, &LOCK_log);
  thd->exit_cond(old_msg);
  DBUG_VOID_RETURN;
}


/**
  Wait until we get a signal that the binary log has been updated.
  Applies to master only.
     
  NOTES
  @param[in] thd        a THD struct
  @param[in] timeout    a pointer to a timespec;
                        NULL means to wait w/o timeout.
  @retval    0          if got signalled on update
  @retval    non-0      if wait timeout elapsed
  @note
    LOCK_log must be taken before calling this function.
    LOCK_log is being released while the thread is waiting.
    LOCK_log is released by the caller.
*/

int MYSQL_BIN_LOG::wait_for_update_bin_log(THD* thd,
                                           const struct timespec *timeout)
{
  int ret= 0;
  const char* old_msg = thd->proc_info;
  DBUG_ENTER("wait_for_update_bin_log");
  old_msg= thd->enter_cond(&update_cond, &LOCK_log,
                           "Master has sent all binlog to slave; "
                           "waiting for binlog to be updated");
  if (!timeout)
    pthread_cond_wait(&update_cond, &LOCK_log);
  else
    ret= pthread_cond_timedwait(&update_cond, &LOCK_log,
                                const_cast<struct timespec *>(timeout));
  DBUG_RETURN(ret);
}


/**
  Close the log file.

  @param exiting     Bitmask for one or more of the following bits:
          - LOG_CLOSE_INDEX : if we should close the index file
          - LOG_CLOSE_TO_BE_OPENED : if we intend to call open
                                     at once after close.
          - LOG_CLOSE_STOP_EVENT : write a 'stop' event to the log

  @note
    One can do an open on the object at once after doing a close.
    The internal structures are not freed until cleanup() is called
*/

void MYSQL_BIN_LOG::close(uint exiting)
{					// One can't set log_type here!
  DBUG_ENTER("MYSQL_BIN_LOG::close");
  DBUG_PRINT("enter",("exiting: %d", (int) exiting));
  if (log_state == LOG_OPENED)
  {
#ifdef HAVE_REPLICATION
    if (log_type == LOG_BIN && !no_auto_events &&
	(exiting & LOG_CLOSE_STOP_EVENT))
    {
      Stop_log_event s;
      s.write(&log_file);
      bytes_written+= s.data_written;
      signal_update();
    }
#endif /* HAVE_REPLICATION */

    /* don't pwrite in a file opened with O_APPEND - it doesn't work */
    if (log_file.type == WRITE_CACHE && log_type == LOG_BIN)
    {
      my_off_t offset= BIN_LOG_HEADER_SIZE + FLAGS_OFFSET;
      my_off_t org_position= my_tell(log_file.file, MYF(0));
      uchar flags= 0;            // clearing LOG_EVENT_BINLOG_IN_USE_F
      pwrite(log_file.file, &flags, 1, offset);
    }

    /* this will cleanup IO_CACHE, sync and close the file */
    MYSQL_LOG::close(exiting);
  }

  /*
    The following test is needed even if is_open() is not set, as we may have
    called a not complete close earlier and the index file is still open.
  */

  if ((exiting & LOG_CLOSE_INDEX) && my_b_inited(&index_file))
  {
    end_io_cache(&index_file);
    if (my_close(index_file.file, MYF(0)) < 0 && ! write_error)
    {
      write_error= 1;
      sql_print_error(ER(ER_ERROR_ON_WRITE), index_file_name, errno);
    }
  }
  log_state= (exiting & LOG_CLOSE_TO_BE_OPENED) ? LOG_TO_BE_OPENED : LOG_CLOSED;
  safeFree(name);
  DBUG_VOID_RETURN;
}


void MYSQL_BIN_LOG::set_max_size(ulong max_size_arg)
{
  /*
    We need to take locks, otherwise this may happen:
    new_file() is called, calls open(old_max_size), then before open() starts,
    set_max_size() sets max_size to max_size_arg, then open() starts and
    uses the old_max_size argument, so max_size_arg has been overwritten and
    it's like if the SET command was never run.
  */
  DBUG_ENTER("MYSQL_BIN_LOG::set_max_size");
  pthread_mutex_lock(&LOCK_log);
  if (is_open())
    max_size= max_size_arg;
  pthread_mutex_unlock(&LOCK_log);
  DBUG_VOID_RETURN;
}


/**
  Check if a string is a valid number.

  @param str			String to test
  @param res			Store value here
  @param allow_wildcards	Set to 1 if we should ignore '%' and '_'

  @note
    For the moment the allow_wildcards argument is not used
    Should be move to some other file.

  @retval
    1	String is a number
  @retval
    0	Error
*/

static bool test_if_number(register const char *str,
			   long *res, bool allow_wildcards)
{
  register int flag;
  const char *start;
  DBUG_ENTER("test_if_number");

  flag= 0; 
  start= str;
  while (*str++ == ' ') ;
  if (*--str == '-' || *str == '+')
    str++;
  while (my_isdigit(files_charset_info,*str) ||
	 (allow_wildcards && (*str == wild_many || *str == wild_one)))
  {
    flag=1;
    str++;
  }
  if (*str == '.')
  {
    for (str++ ;
	 my_isdigit(files_charset_info,*str) ||
	   (allow_wildcards && (*str == wild_many || *str == wild_one)) ;
	 str++, flag=1) ;
  }
  if (*str != 0 || flag == 0)
    DBUG_RETURN(0);
  if (res)
    *res=atol(start);
  DBUG_RETURN(1);			/* Number ok */
} /* test_if_number */


void sql_perror(const char *message)
{
#ifdef HAVE_STRERROR
  sql_print_error("%s: %s",message, strerror(errno));
#else
  perror(message);
#endif
}


bool flush_error_log()
{
  bool result=0;
  if (opt_error_log)
  {
    char err_renamed[FN_REFLEN], *end;
    end= strmake(err_renamed,log_error_file,FN_REFLEN-4);
    strmov(end, "-old");
    VOID(pthread_mutex_lock(&LOCK_error_log));
    char err_temp[FN_REFLEN+4];
    /*
     On Windows is necessary a temporary file for to rename
     the current error file.
    */
    strxmov(err_temp, err_renamed,"-tmp",NullS);
    (void) my_delete(err_temp, MYF(0)); 
    if (freopen(err_temp,"a+",stdout))
    {
      int fd;
      size_t bytes;
      uchar buf[IO_SIZE];

      freopen(err_temp,"a+",stderr);
      (void) my_delete(err_renamed, MYF(0));
      my_rename(log_error_file,err_renamed,MYF(0));
      if (freopen(log_error_file,"a+",stdout))
        freopen(log_error_file,"a+",stderr);

      if ((fd = my_open(err_temp, O_RDONLY, MYF(0))) >= 0)
      {
        while ((bytes= my_read(fd, buf, IO_SIZE, MYF(0))) &&
               bytes != MY_FILE_ERROR)
          my_fwrite(stderr, buf, bytes, MYF(0));
        my_close(fd, MYF(0));
      }
      (void) my_delete(err_temp, MYF(0)); 
    }
    else
     result= 1;
    VOID(pthread_mutex_unlock(&LOCK_error_log));
  }
   return result;
}

void MYSQL_BIN_LOG::signal_update()
{
  DBUG_ENTER("MYSQL_BIN_LOG::signal_update");
  pthread_cond_broadcast(&update_cond);
  DBUG_VOID_RETURN;
}

/**
  Prints a printf style message to the error log and, under NT, to the
  Windows event log.

  This function prints the message into a buffer and then sends that buffer
  to other functions to write that message to other logging sources.

  @param event_type          Type of event to write (Error, Warning, or Info)
  @param format              Printf style format of message
  @param args                va_list list of arguments for the message

  @returns
    The function always returns 0. The return value is present in the
    signature to be compatible with other logging routines, which could
    return an error (e.g. logging to the log tables)
*/
static void print_buffer_to_file(enum loglevel level, int error_code,
                                 const char *buffer, size_t buffer_length)
{
  time_t skr;
  struct tm tm_tmp;
  struct tm *start;
  DBUG_ENTER("print_buffer_to_file");
  DBUG_PRINT("enter",("buffer: %s", buffer));

  VOID(pthread_mutex_lock(&LOCK_error_log));

  skr= my_time(0);
  localtime_r(&skr, &tm_tmp);
  start=&tm_tmp;

  fprintf(stderr, "%02d%02d%02d %2d:%02d:%02d [%s] %s\n",
          start->tm_year % 100,
          start->tm_mon+1,
          start->tm_mday,
          start->tm_hour,
          start->tm_min,
          start->tm_sec,
          (level == ERROR_LEVEL ? "ERROR" : level == WARNING_LEVEL ?
           "Warning" : "Note"),
          buffer);

  fflush(stderr);

  VOID(pthread_mutex_unlock(&LOCK_error_log));
  DBUG_VOID_RETURN;
}


int vprint_msg_to_log(enum loglevel level, const char *format, va_list args)
{
  char   buff[1024];
  size_t length;
  int error_code= errno;
  DBUG_ENTER("vprint_msg_to_log");

  length= vsnprintf(buff, sizeof(buff), format, args);

  print_buffer_to_file(level, error_code, buff, length);

  DBUG_RETURN(0);
}


void sql_print_error(const char *format, ...) 
{
  va_list args;
  DBUG_ENTER("sql_print_error");

  va_start(args, format);
  error_log_print(ERROR_LEVEL, format, args);
  va_end(args);

  DBUG_VOID_RETURN;
}


void sql_print_warning(const char *format, ...) 
{
  va_list args;
  DBUG_ENTER("sql_print_warning");

  va_start(args, format);
  error_log_print(WARNING_LEVEL, format, args);
  va_end(args);

  DBUG_VOID_RETURN;
}


void sql_print_information(const char *format, ...) 
{
  va_list args;
  DBUG_ENTER("sql_print_information");

  va_start(args, format);
  error_log_print(INFORMATION_LEVEL, format, args);
  va_end(args);

  DBUG_VOID_RETURN;
}


/********* transaction coordinator log for 2pc - mmap() based solution *******/

/*
  the log consists of a file, mmapped to a memory.
  file is divided on pages of tc_log_page_size size.
  (usable size of the first page is smaller because of log header)
  there's PAGE control structure for each page
  each page (or rather PAGE control structure) can be in one of three
  states - active, syncing, pool.
  there could be only one page in active or syncing states,
  but many in pool - pool is fifo queue.
  usual lifecycle of a page is pool->active->syncing->pool
  "active" page - is a page where new xid's are logged.
  the page stays active as long as syncing slot is taken.
  "syncing" page is being synced to disk. no new xid can be added to it.
  when the sync is done the page is moved to a pool and an active page
  becomes "syncing".

  the result of such an architecture is a natural "commit grouping" -
  If commits are coming faster than the system can sync, they do not
  stall. Instead, all commit that came since the last sync are
  logged to the same page, and they all are synced with the next -
  one - sync. Thus, thought individual commits are delayed, throughput
  is not decreasing.

  when a xid is added to an active page, the thread of this xid waits
  for a page's condition until the page is synced. when syncing slot
  becomes vacant one of these waiters is awaken to take care of syncing.
  it syncs the page and signals all waiters that the page is synced.
  PAGE::waiters is used to count these waiters, and a page may never
  become active again until waiters==0 (that is all waiters from the
  previous sync have noticed the sync was completed)

  note, that the page becomes "dirty" and has to be synced only when a
  new xid is added into it. Removing a xid from a page does not make it
  dirty - we don't sync removals to disk.
*/

ulong tc_log_page_waits= 0;

#ifdef HAVE_MMAP

#define TC_LOG_HEADER_SIZE (sizeof(tc_log_magic)+1)

static const char tc_log_magic[]={(char) 254, 0x23, 0x05, 0x74};

ulong opt_tc_log_size= TC_LOG_MIN_SIZE;
ulong tc_log_max_pages_used=0, tc_log_page_size=0, tc_log_cur_pages_used=0;

int TC_LOG_MMAP::open(const char *opt_name)
{
  uint i;
  bool crashed=FALSE;
  PAGE *pg;

  DBUG_ASSERT(total_ha_2pc > 1);
  DBUG_ASSERT(opt_name && opt_name[0]);

  tc_log_page_size= my_getpagesize();
  DBUG_ASSERT(TC_LOG_PAGE_SIZE % tc_log_page_size == 0);

  fn_format(logname,opt_name,mysql_data_home,"",MY_UNPACK_FILENAME);
  if ((fd= my_open(logname, O_RDWR, MYF(0))) < 0)
  {
    if (my_errno != ENOENT)
      goto err;
    if (using_heuristic_recover())
      return 1;
    if ((fd= my_create(logname, CREATE_MODE, O_RDWR, MYF(MY_WME))) < 0)
      goto err;
    inited=1;
    file_length= opt_tc_log_size;
    if (ftruncate(fd, file_length))
      goto err;
  }
  else
  {
    inited= 1;
    crashed= TRUE;
    sql_print_information("Recovering after a crash using %s", opt_name);
    if (tc_heuristic_recover)
    {
      sql_print_error("Cannot perform automatic crash recovery when "
                      "--tc-heuristic-recover is used");
      goto err;
    }
    file_length= my_seek(fd, 0L, MY_SEEK_END, MYF(MY_WME+MY_FAE));
    if (file_length == MY_FILEPOS_ERROR || file_length % tc_log_page_size)
      goto err;
  }

  data= (uchar *)my_mmap(0, (size_t)file_length, PROT_READ|PROT_WRITE,
                        MAP_NOSYNC|MAP_SHARED, fd, 0);
  if (data == MAP_FAILED)
  {
    my_errno=errno;
    goto err;
  }
  inited=2;

  npages=(uint)file_length/tc_log_page_size;
  DBUG_ASSERT(npages >= 3);             // to guarantee non-empty pool
  if (!(pages=(PAGE *)my_malloc(npages*sizeof(PAGE), MYF(MY_WME|MY_ZEROFILL))))
    goto err;
  inited=3;
  for (pg=pages, i=0; i < npages; i++, pg++)
  {
    pg->next=pg+1;
    pg->waiters=0;
    pg->state=POOL;
    pthread_mutex_init(&pg->lock, MY_MUTEX_INIT_FAST);
    pthread_cond_init (&pg->cond, 0);
    pg->start=(my_xid *)(data + i*tc_log_page_size);
    pg->ptr=pg->start;
    pg->end=(my_xid *)(pg->start + tc_log_page_size);
    pg->size=pg->free=tc_log_page_size/sizeof(my_xid);
  }
  pages[0].size=pages[0].free=
                (tc_log_page_size-TC_LOG_HEADER_SIZE)/sizeof(my_xid);
  pages[0].start=pages[0].end-pages[0].size;
  pages[npages-1].next=0;
  inited=4;

  if (crashed && recover())
      goto err;

  memcpy(data, tc_log_magic, sizeof(tc_log_magic));
  data[sizeof(tc_log_magic)]= (uchar)total_ha_2pc;
  msync(data, tc_log_page_size, MS_SYNC);
  my_sync(fd, MYF(0));
  inited=5;

  pthread_mutex_init(&LOCK_sync,    MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&LOCK_active,  MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&LOCK_pool,    MY_MUTEX_INIT_FAST);
  pthread_cond_init(&COND_active, 0);
  pthread_cond_init(&COND_pool, 0);

  inited=6;

  syncing= 0;
  active=pages;
  pool=pages+1;
  pool_last=pages+npages-1;

  return 0;

err:
  close();
  return 1;
}

/**
  there is no active page, let's got one from the pool.

  Two strategies here:
    -# take the first from the pool
    -# if there're waiters - take the one with the most free space.

  @todo
    TODO page merging. try to allocate adjacent page first,
    so that they can be flushed both in one sync
*/

void TC_LOG_MMAP::get_active_from_pool()
{
  PAGE **p, **best_p=0;
  int best_free;

  if (syncing)
    pthread_mutex_lock(&LOCK_pool);

  do
  {
    best_p= p= &pool;
    if ((*p)->waiters == 0) // can the first page be used ?
      break;                // yes - take it.

    best_free=0;            // no - trying second strategy
    for (p=&(*p)->next; *p; p=&(*p)->next)
    {
      if ((*p)->waiters == 0 && (*p)->free > best_free)
      {
        best_free=(*p)->free;
        best_p=p;
      }
    }
  }
  while ((*best_p == 0 || best_free == 0) && overflow());

  active=*best_p;
  if (active->free == active->size) // we've chosen an empty page
  {
    tc_log_cur_pages_used++;
    set_if_bigger(tc_log_max_pages_used, tc_log_cur_pages_used);
  }

  if ((*best_p)->next)              // unlink the page from the pool
    *best_p=(*best_p)->next;
  else
    pool_last=*best_p;

  if (syncing)
    pthread_mutex_unlock(&LOCK_pool);
}

/**
  @todo
  perhaps, increase log size ?
*/
int TC_LOG_MMAP::overflow()
{
  /*
    simple overflow handling - just wait
    TODO perhaps, increase log size ?
    let's check the behaviour of tc_log_page_waits first
  */
  tc_log_page_waits++;
  pthread_cond_wait(&COND_pool, &LOCK_pool);
  return 1; // always return 1
}

/**
  Record that transaction XID is committed on the persistent storage.

    This function is called in the middle of two-phase commit:
    First all resources prepare the transaction, then tc_log->log() is called,
    then all resources commit the transaction, then tc_log->unlog() is called.

    All access to active page is serialized but it's not a problem, as
    we're assuming that fsync() will be a main bottleneck.
    That is, parallelizing writes to log pages we'll decrease number of
    threads waiting for a page, but then all these threads will be waiting
    for a fsync() anyway

   If tc_log == MYSQL_LOG then tc_log writes transaction to binlog and
   records XID in a special Xid_log_event.
   If tc_log = TC_LOG_MMAP then xid is written in a special memory-mapped
   log.

  @retval
    0  - error
  @retval
    \# - otherwise, "cookie", a number that will be passed as an argument
    to unlog() call. tc_log can define it any way it wants,
    and use for whatever purposes. TC_LOG_MMAP sets it
    to the position in memory where xid was logged to.
*/

int TC_LOG_MMAP::log_xid(THD *thd, my_xid xid)
{
  int err;
  PAGE *p;
  ulong cookie;

  pthread_mutex_lock(&LOCK_active);

  /*
    if active page is full - just wait...
    frankly speaking, active->free here accessed outside of mutex
    protection, but it's safe, because it only means we may miss an
    unlog() for the active page, and we're not waiting for it here -
    unlog() does not signal COND_active.
  */
  while (unlikely(active && active->free == 0))
    pthread_cond_wait(&COND_active, &LOCK_active);

  /* no active page ? take one from the pool */
  if (active == 0)
    get_active_from_pool();

  p=active;
  pthread_mutex_lock(&p->lock);

  /* searching for an empty slot */
  while (*p->ptr)
  {
    p->ptr++;
    DBUG_ASSERT(p->ptr < p->end);               // because p->free > 0
  }

  /* found! store xid there and mark the page dirty */
  cookie= (ulong)((uchar *)p->ptr - data);      // can never be zero
  *p->ptr++= xid;
  p->free--;
  p->state= DIRTY;

  /* to sync or not to sync - this is the question */
  pthread_mutex_unlock(&LOCK_active);
  pthread_mutex_lock(&LOCK_sync);
  pthread_mutex_unlock(&p->lock);

  if (syncing)
  {                                          // somebody's syncing. let's wait
    p->waiters++;
    /*
      note - it must be while (), not do ... while () here
      as p->state may be not DIRTY when we come here
    */
    while (p->state == DIRTY && syncing)
      pthread_cond_wait(&p->cond, &LOCK_sync);
    p->waiters--;
    err= p->state == ERROR;
    if (p->state != DIRTY)                   // page was synced
    {
      if (p->waiters == 0)
        pthread_cond_signal(&COND_pool);     // in case somebody's waiting
      pthread_mutex_unlock(&LOCK_sync);
      goto done;                             // we're done
    }
  }                                          // page was not synced! do it now
  DBUG_ASSERT(active == p && syncing == 0);
  pthread_mutex_lock(&LOCK_active);
  syncing=p;                                 // place is vacant - take it
  active=0;                                  // page is not active anymore
  pthread_cond_broadcast(&COND_active);      // in case somebody's waiting
  pthread_mutex_unlock(&LOCK_active);
  pthread_mutex_unlock(&LOCK_sync);
  err= sync();

done:
  return err ? 0 : cookie;
}

int TC_LOG_MMAP::sync()
{
  int err;

  DBUG_ASSERT(syncing != active);

  /*
    sit down and relax - this can take a while...
    note - no locks are held at this point
  */
  err= msync(syncing->start, 1, MS_SYNC);
  if(err==0)
    err= my_sync(fd, MYF(0));

  /* page is synced. let's move it to the pool */
  pthread_mutex_lock(&LOCK_pool);
  pool_last->next=syncing;
  pool_last=syncing;
  syncing->next=0;
  syncing->state= err ? ERROR : POOL;
  pthread_cond_broadcast(&syncing->cond);    // signal "sync done"
  pthread_cond_signal(&COND_pool);           // in case somebody's waiting
  pthread_mutex_unlock(&LOCK_pool);

  /* marking 'syncing' slot free */
  pthread_mutex_lock(&LOCK_sync);
  syncing=0;
  pthread_cond_signal(&active->cond);        // wake up a new syncer
  pthread_mutex_unlock(&LOCK_sync);
  return err;
}

/**
  erase xid from the page, update page free space counters/pointers.
  cookie points directly to the memory where xid was logged.
*/

void TC_LOG_MMAP::unlog(ulong cookie, my_xid xid)
{
  PAGE *p=pages+(cookie/tc_log_page_size);
  my_xid *x=(my_xid *)(data+cookie);

  DBUG_ASSERT(*x == xid);
  DBUG_ASSERT(x >= p->start && x < p->end);
  *x=0;

  pthread_mutex_lock(&p->lock);
  p->free++;
  DBUG_ASSERT(p->free <= p->size);
  set_if_smaller(p->ptr, x);
  if (p->free == p->size)               // the page is completely empty
    statistic_decrement(tc_log_cur_pages_used, &LOCK_status);
  if (p->waiters == 0)                 // the page is in pool and ready to rock
    pthread_cond_signal(&COND_pool);   // ping ... for overflow()
  pthread_mutex_unlock(&p->lock);
}

void TC_LOG_MMAP::close()
{
  uint i;
  switch (inited) {
  case 6:
    pthread_mutex_destroy(&LOCK_sync);
    pthread_mutex_destroy(&LOCK_active);
    pthread_mutex_destroy(&LOCK_pool);
    pthread_cond_destroy(&COND_pool);
  case 5:
    data[0]='A'; // garble the first (signature) byte, in case my_delete fails
  case 4:
    for (i=0; i < npages; i++)
    {
      if (pages[i].ptr == 0)
        break;
      pthread_mutex_destroy(&pages[i].lock);
      pthread_cond_destroy(&pages[i].cond);
    }
  case 3:
    my_free((uchar*)pages, MYF(0));
  case 2:
    my_munmap((char*)data, (size_t)file_length);
  case 1:
    my_close(fd, MYF(0));
  }
  if (inited>=5) // cannot do in the switch because of Windows
    my_delete(logname, MYF(MY_WME));
  inited=0;
}

int TC_LOG_MMAP::recover()
{
  HASH xids;
  PAGE *p=pages, *end_p=pages+npages;

  if (memcmp(data, tc_log_magic, sizeof(tc_log_magic)))
  {
    sql_print_error("Bad magic header in tc log");
    goto err1;
  }

  /*
    the first byte after magic signature is set to current
    number of storage engines on startup
  */
  if (data[sizeof(tc_log_magic)] != total_ha_2pc)
  {
    sql_print_error("Recovery failed! You must enable "
                    "exactly %d storage engines that support "
                    "two-phase commit protocol",
                    data[sizeof(tc_log_magic)]);
    goto err1;
  }

  if (hash_init(&xids, &my_charset_bin, tc_log_page_size/3, 0,
                sizeof(my_xid), 0, 0, MYF(0)))
    goto err1;

  for ( ; p < end_p ; p++)
  {
    for (my_xid *x=p->start; x < p->end; x++)
      if (*x && my_hash_insert(&xids, (uchar *)x))
        goto err2; // OOM
  }

  if (ha_recover(&xids))
    goto err2;

  hash_free(&xids);
  bzero(data, (size_t)file_length);
  return 0;

err2:
  hash_free(&xids);
err1:
  sql_print_error("Crash recovery failed. Either correct the problem "
                  "(if it's, for example, out of memory error) and restart, "
                  "or delete tc log and start mysqld with "
                  "--tc-heuristic-recover={commit|rollback}");
  return 1;
}
#endif

TC_LOG *tc_log;
TC_LOG_DUMMY tc_log_dummy;
TC_LOG_MMAP  tc_log_mmap;

/**
  Perform heuristic recovery, if --tc-heuristic-recover was used.

  @note
    no matter whether heuristic recovery was successful or not
    mysqld must exit. So, return value is the same in both cases.

  @retval
    0	no heuristic recovery was requested
  @retval
    1   heuristic recovery was performed
*/

int TC_LOG::using_heuristic_recover()
{
  if (!tc_heuristic_recover)
    return 0;

  sql_print_information("Heuristic crash recovery mode");
  if (ha_recover(0))
    sql_print_error("Heuristic crash recovery failed");
  sql_print_information("Please restart mysqld without --tc-heuristic-recover");
  return 1;
}

/****** transaction coordinator log for 2pc - binlog() based solution ******/
#define TC_LOG_BINLOG MYSQL_BIN_LOG

/**
  @todo
  keep in-memory list of prepared transactions
  (add to list in log(), remove on unlog())
  and copy it to the new binlog if rotated
  but let's check the behaviour of tc_log_page_waits first!
*/

int TC_LOG_BINLOG::open(const char *opt_name)
{
  LOG_INFO log_info;
  int      error= 1;

  DBUG_ASSERT(total_ha_2pc > 1);
  DBUG_ASSERT(opt_name && opt_name[0]);

  pthread_mutex_init(&LOCK_prep_xids, MY_MUTEX_INIT_FAST);
  pthread_cond_init (&COND_prep_xids, 0);

  if (!my_b_inited(&index_file))
  {
    /* There was a failure to open the index file, can't open the binlog */
    cleanup();
    return 1;
  }

  if (using_heuristic_recover())
  {
    /* generate a new binlog to mask a corrupted one */
    open(opt_name, LOG_BIN, 0, WRITE_CACHE, 0, max_binlog_size, 0);
    cleanup();
    return 1;
  }

  if ((error= find_log_pos(&log_info, NullS, 1)))
  {
    if (error != LOG_INFO_EOF)
      sql_print_error("find_log_pos() failed (error: %d)", error);
    else
      error= 0;
    goto err;
  }

  {
    const char *errmsg;
    IO_CACHE    log;
    File        file;
    Log_event  *ev=0;
    Format_description_log_event fdle(BINLOG_VERSION);
    char        log_name[FN_REFLEN];

    if (! fdle.is_valid())
      goto err;

    do
    {
      strmake(log_name, log_info.log_file_name, sizeof(log_name)-1);
    } while (!(error= find_next_log(&log_info, 1)));

    if (error !=  LOG_INFO_EOF)
    {
      sql_print_error("find_log_pos() failed (error: %d)", error);
      goto err;
    }

    if ((file= open_binlog(&log, log_name, &errmsg)) < 0)
    {
      sql_print_error("%s", errmsg);
      goto err;
    }

    if ((ev= Log_event::read_log_event(&log, 0, &fdle)) &&
        ev->get_type_code() == FORMAT_DESCRIPTION_EVENT &&
        ev->flags & LOG_EVENT_BINLOG_IN_USE_F)
    {
      sql_print_information("Recovering after a crash using %s", opt_name);
      error= recover(&log, (Format_description_log_event *)ev);
    }
    else
      error=0;

    delete ev;
    end_io_cache(&log);
    my_close(file, MYF(MY_WME));

    if (error)
      goto err;
  }

err:
  return error;
}

/** This is called on shutdown, after ha_panic. */
void TC_LOG_BINLOG::close()
{
  DBUG_ASSERT(prepared_xids==0);
  pthread_mutex_destroy(&LOCK_prep_xids);
  pthread_cond_destroy (&COND_prep_xids);
}

/**
  @todo
  group commit

  @retval
    0    error
  @retval
    1    success
*/
int TC_LOG_BINLOG::log_xid(THD *thd, my_xid xid)
{
  DBUG_ENTER("TC_LOG_BINLOG::log");
  Xid_log_event xle(thd, xid);
  binlog_trx_data *trx_data=
    (binlog_trx_data*) thd_get_ha_data(thd, binlog_hton);
  /*
    We always commit the entire transaction when writing an XID. Also
    note that the return value is inverted.
   */
  DBUG_RETURN(!binlog_end_trans(thd, trx_data, &xle, TRUE));
}

void TC_LOG_BINLOG::unlog(ulong cookie, my_xid xid)
{
  pthread_mutex_lock(&LOCK_prep_xids);
  DBUG_ASSERT(prepared_xids > 0);
  if (--prepared_xids == 0) {
    DBUG_PRINT("info", ("prepared_xids=%lu", prepared_xids));
    pthread_cond_signal(&COND_prep_xids);
  }
  pthread_mutex_unlock(&LOCK_prep_xids);
  rotate_and_purge(0);     // as ::write() did not rotate
}

int TC_LOG_BINLOG::recover(IO_CACHE *log, Format_description_log_event *fdle)
{
  Log_event  *ev;
  HASH xids;
  MEM_ROOT mem_root;

  if (! fdle->is_valid() ||
      hash_init(&xids, &my_charset_bin, TC_LOG_PAGE_SIZE/3, 0,
                sizeof(my_xid), 0, 0, MYF(0)))
    goto err1;

  init_alloc_root(&mem_root, TC_LOG_PAGE_SIZE, TC_LOG_PAGE_SIZE);

  fdle->flags&= ~LOG_EVENT_BINLOG_IN_USE_F; // abort on the first error

  while ((ev= Log_event::read_log_event(log,0,fdle)) && ev->is_valid())
  {
    if (ev->get_type_code() == XID_EVENT)
    {
      Xid_log_event *xev=(Xid_log_event *)ev;
      uchar *x= (uchar *) memdup_root(&mem_root, (uchar*) &xev->xid,
                                      sizeof(xev->xid));
      if (! x)
        goto err2;
      my_hash_insert(&xids, x);
    }
    delete ev;
  }

  if (ha_recover(&xids))
    goto err2;

  free_root(&mem_root, MYF(0));
  hash_free(&xids);
  return 0;

err2:
  free_root(&mem_root, MYF(0));
  hash_free(&xids);
err1:
  sql_print_error("Crash recovery failed. Either correct the problem "
                  "(if it's, for example, out of memory error) and restart, "
                  "or delete (or rename) binary log and start mysqld with "
                  "--tc-heuristic-recover={commit|rollback}");
  return 1;
}


#ifdef INNODB_COMPATIBILITY_HOOKS
/**
  Get the file name of the MySQL binlog.
  @return the name of the binlog file
*/
extern "C"
const char* mysql_bin_log_file_name(void)
{
  return mysql_bin_log.get_log_fname();
}
/**
  Get the current position of the MySQL binlog.
  @return byte offset from the beginning of the binlog
*/
extern "C"
ulonglong mysql_bin_log_file_pos(void)
{
  return (ulonglong) mysql_bin_log.get_log_file()->pos_in_file;
}
#endif /* INNODB_COMPATIBILITY_HOOKS */


struct st_mysql_storage_engine binlog_storage_engine=
{ MYSQL_HANDLERTON_INTERFACE_VERSION };

mysql_declare_plugin(binlog)
{
  MYSQL_STORAGE_ENGINE_PLUGIN,
  &binlog_storage_engine,
  "binlog",
  "MySQL AB",
  "This is a pseudo storage engine to represent the binlog in a transaction",
  PLUGIN_LICENSE_GPL,
  binlog_init, /* Plugin Init */
  NULL, /* Plugin Deinit */
  0x0100 /* 1.0 */,
  NULL,                       /* status variables                */
  NULL,                       /* system variables                */
  NULL                        /* config options                  */
}
mysql_declare_plugin_end;