4 ms·

I stopped reading after the first sentence. The author takes some liberties with the definition of "eventual consistency.". Either he doesn't know what it mean

by codex 15y ago

I stopped reading after the first sentence. The author takes some liberties with the definition of "eventual consistency.". Either he doesn't know what it means, or he likes to demolish terms which used to be defined precisely.

cdavid 15y ago
Or maybe you are expecting one context and the author is using a different one. This is quite likely given the author (a well known hacker, and having worked in particular on this exact problem through his project codeville)
random42 15y ago
On a related note, to establish the credential of the author, he is the creator of BitTorrent protocol. http://en.wikipedia.org/wiki/Bram_Cohen http://en.wikipedia.org/wiki/Bram_Cohen
- jacobolus 15y ago
  And has worked quite a bit on the revision control diff/merge problem, e.g. http://bramcohen.livejournal.com/37690.html http://bramcohen.livejournal.com/37690.html
shasta 15y ago
Why do you think he's using the term incorrectly? He just means that, with git, the order in which you apply patches matters. In a scenario where people are distributing patches and applying them as they receive them, this implies a lack of eventual consistency.
- codex 15y ago
  That's the lack of the associative property. Eventual consistency means that updates will eventually be propagated to all replicas in a distributed system and that all replicas will be consistent. Not the same thing, at all.
  - shasta 15y ago
    Commutative, not associative. And the commutative property is exactly what's required to guarantee eventual consistency when patches are being applied in the order they are received since it ensures that order of application doesn't matter. Of course, if you have all of the updates, you can achieve eventual consistency without commutativity by periodically reapplying all of the patches from scratch in a deterministic order. But IMO his intended meaning was both clear and correct.

by codex 15y ago

cdavid 15y ago

Or maybe you are expecting one context and the author is using a different one. This is quite likely given the author (a well known hacker, and having worked in particular on this exact problem through his project codeville)

random42 15y ago

On a related note, to establish the credential of the author, he is the creator of BitTorrent protocol. http://en.wikipedia.org/wiki/Bram_Cohen http://en.wikipedia.org/wiki/Bram_Cohen

jacobolus 15y ago
And has worked quite a bit on the revision control diff/merge problem, e.g. http://bramcohen.livejournal.com/37690.html http://bramcohen.livejournal.com/37690.html

shasta 15y ago

Why do you think he's using the term incorrectly? He just means that, with git, the order in which you apply patches matters. In a scenario where people are distributing patches and applying them as they receive them, this implies a lack of eventual consistency.

codex 15y ago
That's the lack of the associative property. Eventual consistency means that updates will eventually be propagated to all replicas in a distributed system and that all replicas will be consistent. Not the same thing, at all.
- shasta 15y ago
  Commutative, not associative. And the commutative property is exactly what's required to guarantee eventual consistency when patches are being applied in the order they are received since it ensures that order of application doesn't matter. Of course, if you have all of the updates, you can achieve eventual consistency without commutativity by periodically reapplying all of the patches from scratch in a deterministic order. But IMO his intended meaning was both clear and correct.