Function handle_slave_sql

sql/slave.cc:5157–5736

Slave SQL thread entry point. @param arg Pointer to Relay_log_info object that holds information for the SQL thread. @return Always 0. */

  @return Always 0.
*/
pthread_handler_t handle_slave_sql(void *arg)
{
  THD *thd;                     /* needs to be first for thread_stack */
  char saved_log_name[FN_REFLEN];
  char saved_master_log_name[FN_REFLEN];
  bool thd_initialized= 0;
  my_off_t UNINIT_VAR(saved_log_pos);
  my_off_t UNINIT_VAR(saved_master_log_pos);
  String saved_skip_gtid_pos;
  my_off_t saved_skip= 0;
  Master_info *mi= ((Master_info*)arg);
  Relay_log_info* rli = &mi->rli;
  my_bool wsrep_node_dropped __attribute__((unused)) = FALSE;
  const char *errmsg;
  rpl_group_info *serial_rgi;
  rpl_sql_thread_info sql_info(mi->rpl_filter);

  // needs to call my_thread_init(), otherwise we get a coredump in DBUG_ stuff
  my_thread_init();
  my_thread_set_name("slave_sql");
  DBUG_ENTER("handle_slave_sql");

#ifdef WITH_WSREP
 wsrep_restart_point:
#endif

  serial_rgi= new rpl_group_info(rli);
  thd = new THD(next_thread_id()); // note that contructor of THD uses DBUG_ !
  thd->thread_stack= (void*) &thd; // Big stack, remember where our stack is
  thd->system_thread_info.rpl_sql_info= &sql_info;

  DBUG_ASSERT(rli->inited);
  DBUG_ASSERT(rli->mi == mi);

  /*
    Reset errors for a clean start (otherwise, if the master is idle, the SQL
    thread may execute no Query_log_event, so the error will remain even
    though there's no problem anymore). Do not reset the master timestamp
    (imagine the slave has caught everything, the STOP SLAVE and START SLAVE:
    as we are not sure that we are going to receive a query, we want to
    remember the last master timestamp (to say how many seconds behind we are
    now.
    But the master timestamp is reset by RESET SLAVE & CHANGE MASTER.
  */
  rli->clear_error();

  mysql_mutex_lock(&rli->run_lock);
  DBUG_ASSERT(!rli->slave_running);
  errmsg= 0;
#ifndef DBUG_OFF
  rli->events_till_abort = abort_slave_event_count;
#endif

  /*
    THD for the sql driver thd. In parallel replication this is the thread
    that reads things from the relay log and calls rpl_parallel::do_event()
    to execute queries.