How to specify payload size

[leisun124]

with data topic idl like this:
struct myData
{
unsigned long len;
octect message[1024];
}
The message size can be really small. say 10 bytes, but fast-dds always serialize the entire 1024 bytes to network, isn't it? I can't use sequence octet, as that translated to std::vector<uint8_t> , and I can't use zerocopy since the data type is not plain anymore.
Any idea to improve to get best performance?
THank
Lei

[JesusPoderoso]

Hi @leisun124, thanks for using Fast DDS.
You need to use bounded types among other constraints if you want to use the Zero-Copy mechanism with Data-sharing.
If your deployment is in the same host, you can consider using Zero-Copy mechanism with Intra-process delivery.
If that does not suit you, your remaining option is Shared Memory Transport.
You can check in this discussion thread the benefits / amount of data copies per delivery method.