[Spread-users] Flow Control

[koorosh.alahiari at ids.allianz.com]

Hi All,

This is more of a twicking your brain kind of question than an spread one!
Does anyone have any bright ideas on how to do flow control (and reliable
delivery) at the application level:

I have implemented an ACK mechanism that is not good enough(because the
overhead does degrade my clients' user programs by a factor that I am not
happy
with). Here is how I do it:

I use Berkeley DB for persisting my message queue (which adds some overhead
even if it is done in a seperate thread). For every message that an
application sends
my interface expects and ACK message (which it does NOT deliver to the
application).
It only deletes the original message when it receives the ACK. This is
straight forward
enough BUT the problematic part arises due to group-wide mode of operation.
Should I wait for all members to acknowledge, what would I do with a slow
member
(which is going to slow down the whole "club"?). This is also true for flow
control, do
I do flow control on the fastest member, slowest member, etc.

If someone could put me at the direction of some publications - or even
better
some practical solutions - I would appreciate it.

I probably have not explained things very well but I am sure that you have
come
across this issue many times before and can work out what I am trying to
say!

Many thanks for this fine piece of software (spread) & regards,

Koorosh