Function do_command

sql/sql_parse.cc:1225–1474

*/

dispatch_command_return do_command(THD *thd, bool blocking)
{
  dispatch_command_return return_value;
  char *packet= 0;
  ulong packet_length;
  NET *net= &thd->net;
  enum enum_server_command command;
  DBUG_ENTER("do_command");

#ifdef WITH_WSREP
  DBUG_ASSERT(!thd->async_state.pending_ops() ||
              (WSREP(thd) &&
               thd->wsrep_trx().state() == wsrep::transaction::s_aborted));
#else
  DBUG_ASSERT(!thd->async_state.pending_ops());
#endif

  if (thd->async_state.m_state == thd_async_state::enum_async_state::RESUMED)
  {
    /*
     Resuming previously suspended command.
     Restore the state
    */
    command = thd->async_state.m_command;
    packet = thd->async_state.m_packet.str;
    packet_length = (ulong)thd->async_state.m_packet.length;
    goto resume;
  }

  /*
    indicator of uninitialized lex => normal flow of errors handling
    (see my_message_sql)
  */
  thd->lex->current_select= 0;

  /*
    This thread will do a blocking read from the client which
    will be interrupted when the next command is received from
    the client, the connection is closed or "net_wait_timeout"
    number of seconds has passed.
  */
  if (!thd->skip_wait_timeout)
    my_net_set_read_timeout(net, thd->get_net_wait_timeout());

  /* Errors and diagnostics are cleared once here before query */
  thd->clear_error(1);

  net_new_transaction(net);

  /* Save for user statistics */
  thd->start_bytes_received= thd->status_var.bytes_received;

  /*
    Synchronization point for testing of KILL_CONNECTION.
    This sync point can wait here, to simulate slow code execution
    between the last test of thd->killed and blocking in read().

    The goal of this test is to verify that a connection does not