Legacy Issue Number: 16558
Source: ZettaScale Technology ( Angelo Corsaro, PhD.)
Key attributes and Regular attributes of a topic should be individually de-serializable (or at least make the keyhash compulsory)
The "DDS Interoperability Wire Protocol v2.1" defines a a serialization format for topic types in which
it is not easy, nor efficient, to simply get access to the key of a given topic. This has to do with how CDR
serializes structs but could be worked around with the new X-Types specification.
In essence the problem is that some applications such as DDS routers (such as the PrismTech BlendBox)
require to perform some operations that while requiring a knowledge of the instance do not require the deserialization
of the data payload.
For DDS implementation compatible with the X-Types ensure that the regular data attributes and the key attributes are serialized
in different chunks and thus individually accessible in an efficient manner – meaning to access the key I would prefer not to scan all
the regular attributes.
For non X-Types compatible DDS implementations make the KeyHash compulsory, meaning require DDS compliant implementation to
always send a key-hash along with a Data submessage.
Reported: DDSI-RTPS 2.0b1 — Mon, 19 Sep 2011 04:00 GMT
Disposition: Closed; No Change — DDSI-RTPS 2.3
No immediate need to add individual serialization of keys and regular attributes
The RTF does not see an immediate need to add the proposed functionality to the specification.
Updated: Wed, 19 Dec 2018 16:38 GMT