Method purge_first_log

phx_percona/percona/sql/binlog.cc:4191–4295

#ifdef HAVE_REPLICATION

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

  DBUG_ASSERT(current_thd->system_thread == SYSTEM_THREAD_SLAVE_SQL);
  DBUG_ASSERT(is_relay_log);
  DBUG_ASSERT(is_open());
  DBUG_ASSERT(rli->slave_running == 1);
  DBUG_ASSERT(!strcmp(rli->linfo.log_file_name,rli->get_event_relay_log_name()));

  mysql_mutex_assert_owner(&rli->data_lock);

  mysql_mutex_lock(&LOCK_index);
  to_purge_if_included= my_strdup(rli->get_group_relay_log_name(), MYF(0));

  /*
    Read the next log file name from the index file and pass it back to
    the caller.
  */
  if((error=find_log_pos(&rli->linfo, rli->get_event_relay_log_name(),
                         false/*need_lock_index=false*/)) ||
     (error=find_next_log(&rli->linfo, false/*need_lock_index=false*/)))
  {
    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->get_event_relay_log_name(),
                    included);
    goto err;
  }

  /*
    Reset rli's coordinates to the current log.
  */
  rli->set_event_relay_log_pos(BIN_LOG_HEADER_SIZE);
  rli->set_event_relay_log_name(rli->linfo.log_file_name);

  /*
    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->set_group_relay_log_pos(BIN_LOG_HEADER_SIZE);
    rli->set_group_relay_log_name(rli->linfo.log_file_name);
    rli->notify_group_relay_log_name_update();
  }
  /*
    Store where we are in the new file for the execution thread.
    If we are in the middle of a group), then we should not store
    the position in the repository, instead in that case set a flag
    to true which indicates that a 'forced flush' is postponed due
    to transaction split across the relaylogs.
  */