Spider supports (or at least allows) INSERT DELAYED but the
documentation does not specify spider as a storage engine that supports
"INSERT DELAYED".
Also, although not mentioned in the documentation, "INSERT DELAYED" is
not intended to be executed inside a transaction, as can be seen from
the list of supported storage engines.
The current implementation allows executing a delayed insert on a
remote transactional table and this breaks the consistency ensured by
the transaction.

We too remove "internal_delayed", one of the Spider table parameters.
Documentation says,

> Whether to transmit existence of delay to remote servers when
> executing an INSERT DELAYED statement on local server.

This table parameter is only used for "INSERT DELAYED".

Reviewed by: Nayuta Yanagisawa