[Spread-users] Re: [Spread-users]: Max time delivery?

[Theo Schlossnagle]

Jonathan Stanton wrote:

>An interesting problem that occurs with this type of feature is that it is
>not clear in a distributed system who's clock represents 'real' time. If
>one clock is slow and so the message is marked as being sent an hour ago,
>should it be discarded immediately upon reaching another machine?
>  
>
My two cents... partially unrelated.  Clocks being out of sync?  Not 
Spread's problem.  I think it is safe for any application to rely on 
 the system clocks of its cluster being in sync to the nearest 100ms or 
so... It is a solved problem. "It's NTPs responsibility... not Spread's".

As for having this feature in spread:  I guess I can see the advantage 
of doing this in the daemon, because the user doesn't need to get the 
message and then discard it, but aside from that, it is trivial to 
implement this at the application level.  Unless there is a really 
compelling reason to implement this in Spread (like reducing network 
traffic tremendouly because you have many non-local clients and many 
late messages, then I think it should be handled in the app -- it is 
much more flexible.

-- 
Theo Schlossnagle
Principal Consultant
OmniTI Computer Consulting, Inc. -- http://www.omniti.com/
Phone:  +1 301 776 6376       Fax:  +1 410 880 4879
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