The backend MySQL protocol module now supports a new routing capability
which allows result sets to be gathered into one buffer before they are
routed onward. This should not be used by modules that expect large
result sets as the result set is buffered in memory.
Adding a limit on how large of a result set could be buffered would allow
relatively safe use of this routing capability without compromising the
stability of the system.
The routing capabilities now define the type of output the reply
processing chain expects. Currently, this only consists of two
capabilities; complete packet output and contiguous buffer output. The
latter implies the former.
The transaction state must be updated after a buffer has been split
into buffer containing individual packets.
NOTE: The actual updating of the transaction state and the autocommit
mode is currently wrong, but will be updated in a subsequent change.
Common capabilities are now defined in routing.h. The common
capabilities can be defined using bits 0 - 15.
Router capabilities are defined using bits 16-31 and filter
capabilities (should there ever be such) using bits 32-47.
So, to find out the capabilities of a service you only need to
OR the capabilities of the router and all filters together.
For instance, if a single filter needs statement based routing,
then that is what is done.
