Function wait_for_master

sql/sql_table.cc:10395–10435

Wait for master to send result of Alter table. Returns true when Rollback is decided false otherwise */

     false   otherwise
*/
static bool wait_for_master(THD *thd)
{
#ifdef HAVE_REPLICATION
  start_alter_info* info= thd->rgi_slave->sa_info;
  Master_info *mi= thd->rgi_slave->rli->mi;

  DBUG_ASSERT(info);
  DBUG_ASSERT(info->state != start_alter_state::INVALID);
  DBUG_ASSERT(mi);

  mysql_mutex_lock(&mi->start_alter_lock);

  DBUG_ASSERT(!info->direct_commit_alter ||
              info->state == start_alter_state::ROLLBACK_ALTER);

  while (info->state == start_alter_state::REGISTERED)
  {
    mysql_cond_wait(&info->start_alter_cond, &mi->start_alter_lock);
  }
  if (info->state == start_alter_state::ROLLBACK_ALTER)
  {
    /*
      SA thread will not give error , We will set the error in info->error
      and then RA worker will output the error
      We can modify the info->error without taking mutex, because CA worker
      will be waiting on ::COMPLETED wait condition
    */
    if(thd->is_error())
    {
      info->error= thd->get_stmt_da()->sql_errno();
      thd->clear_error();
      thd->reset_killed();
    }
  }
  mysql_mutex_unlock(&mi->start_alter_lock);

  return info->state == start_alter_state::ROLLBACK_ALTER;
#else
  return 0;
#endif
}

#ifdef HAVE_REPLICATION
/**