[Spread-users] What are "CAUSAL" messages?

John Schultz jschultz at d-fusion.net
Fri Jul 19 16:17:56 EDT 2002


Or put another way, if you causally send a message m' in response to 
(after receiving/delivering) a previous message m then anyone who 
receives both m and m' will see m before m'.

This way no one will ever see a response followed by the request that 
caused the response.

John

Ben Laurie wrote:

> Ned Konz wrote:
> 
>> This may be a stupid question, but I haven't seen it answered anywhere:
>>
>> What is a Causal message, and why or when would I want one?
>>
>> I understand that it is a kind of ordering guarantee, but I don't 
>> understand what the ordering is or when it matters.
> 
> 
> Causal means that if anyone receives message A before they send message 
> B, then everyone is guaranteed to also get A before B (i.e. causal 
> ordering, in the physics sense, is preserved).
> 
> Cheers,
> 
> Ben.
> 






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