Function threadpool_process_request

sql/threadpool_common.cc:400–466

Process a single client request or a single batch. */

 Process a single client request or a single batch.
*/
static dispatch_command_return threadpool_process_request(THD *thd)
{
  dispatch_command_return retval= DISPATCH_COMMAND_SUCCESS;

  thread_attach(thd);
  if(thd->async_state.m_state == thd_async_state::enum_async_state::RESUMED)
    goto resume;

  if (thd->killed >= KILL_CONNECTION)
  {
    /*
      killed flag was set by timeout handler
      or KILL command. Return error.
    */
    retval= DISPATCH_COMMAND_CLOSE_CONNECTION;
    if(thd->killed == KILL_WAIT_TIMEOUT)
      handle_wait_timeout(thd);
    goto end;
  }


  /*
    In the loop below, the flow is essentially the copy of
    thread-per-connections
    logic, see do_handle_one_connection() in sql_connect.c

    The goal is to execute a single query, thus the loop is normally executed 
    only once. However for SSL connections, it can be executed multiple times 
    (SSL can preread and cache incoming data, and vio->has_data() checks if it 
    was the case).
  */
  for(;;)
  {
    thd->net.reading_or_writing= 0;
    if (mysql_audit_release_required(thd))
      mysql_audit_release(thd);

resume:
    retval= do_command(thd, false);
    switch(retval)
    {
      case DISPATCH_COMMAND_WOULDBLOCK:
      case DISPATCH_COMMAND_CLOSE_CONNECTION:
        goto end;
      case DISPATCH_COMMAND_SUCCESS:
        break;
    }

    if (!thd_is_connection_alive(thd))
    {
      retval=DISPATCH_COMMAND_CLOSE_CONNECTION;
      goto end;
    }

    set_thd_idle(thd);

    if (!has_unread_data(thd))
    {