Imported from previous forum
Hi,
I have a question on communicating array sizes in FAST. I’m sending a message with sub messages.
When packing the parent message into the data buffer, if there are repeating blocks, the number of repeating blocks will be included prior to the repeating blocks according to the FAST implementation.
Do I have to send the number of repeating blocks explicitly in a separate field though that’s anyway included in the data?
As I feel, sending that count separately is duplicate. When considering a large number of FAST clients this increases the bandwidth utilization.
I’m really grateful to you if you could help me in finding the correct implementation.
Thank you,
Sajith
Sajith -
You’re correct, you shouldn’t send the number of repeated groups as a separate field in FAST.
The practice to send the count as an ordinary field is an artifact of the FIX tag/value encoding and should be avoided when there are other intrinsic means to do this (like the sequence length preamble in FAST).
/David
Hi,
I have a question on communicating array sizes in FAST. I’m sending a
message with sub messages.When packing the parent message into the data buffer, if there are
repeating blocks, the number of repeating blocks will be included prior
to the repeating blocks according to the FAST implementation.Do I have to send the number of repeating blocks explicitly in a
separate field though that’s anyway included in the data?As I feel, sending that count separately is duplicate. When considering
a large number of FAST clients this increases the bandwidth utilization.I’m really grateful to you if you could help me in finding the correct
implementation.Thank you, Sajith
Thanks a lot David! Your quick response is really appreciated.
Sajith -
You’re correct, you shouldn’t send the number of repeated groups as a
separate field in FAST.The practice to send the count as an ordinary field is an artifact of
the FIX tag/value encoding and should be avoided when there are other
intrinsic means to do this (like the sequence length preamble in FAST)./David
Hi,
I have a question on communicating array sizes in FAST. I’m sending a
message with sub messages.When packing the parent message into the data buffer, if there are
repeating blocks, the number of repeating blocks will be included
prior to the repeating blocks according to the FAST implementation.Do I have to send the number of repeating blocks explicitly in a
separate field though that’s anyway included in the data?As I feel, sending that count separately is duplicate. When
considering a large number of FAST clients this increases the
bandwidth utilization.I’m really grateful to you if you could help me in finding the correct
implementation.Thank you, Sajith
Sajith,
David is correct. In fact the cleanest way to handle this is to explicitly describe the length field of the sequence in the template using the element. This lets you use the FIX field name and tag as the name and ID of the length field.
Dale
You’re correct, you shouldn’t send the number of repeated groups as a
separate field in FAST.The practice to send the count as an ordinary field is an artifact
of the FIX tag/value encoding and should be avoided when there are
other intrinsic means to do this (like the sequence length preamble
in FAST)./David
Hi,
I have a question on communicating array sizes in FAST. I’m sending
a message with sub messages.When packing the parent message into the data buffer, if there are
repeating blocks, the number of repeating blocks will be included
prior to the repeating blocks according to the FAST implementation.Do I have to send the number of repeating blocks explicitly in a
separate field though that’s anyway included in the data?As I feel, sending that count separately is duplicate. When
considering a large number of FAST clients this increases the
bandwidth utilization.I’m really grateful to you if you could help me in finding the
correct implementation.Thank you, Sajith