[MUD-Dev] On Lockless Threading and X/Open XA

[J C Lawrence]

On Tue, 01 Aug 2000 15:54:14 +1000 
KevinL  <darius at bofh.net.au> wrote:

> Seriously, there's a batch of problems out there for mud's with
> separated data stores that _might_ bite, and there's a bunch of
> situations that _might_ confuse the player - weird little locking
> issues.  If you want to be thorough, fixing them becomes fairly
> expensive in terms of the complexity of the algorithm.

Distributed locking systems are non-trivial once you get into the
corner cases, especially if you allow data migration and cacheing
(which are really just data locality issues).  On Friday I had a
rather interesting interview Akamai which hit on these areas fairly
well (think about their problems as regards say SSL sites,
authentication and session ID tracking, etc).  Correctly defining a
distributed algebra when both the nodes and interconnects are
unreliable is not easy.

Last time I dug in this area I started with the Free DB list
(there's a link in the Library) and dug out from there.  IIRC there
are about a half dozen free DBs which implement distributed stores
to some extent with Arjuna seeming the most interesting (or at least
it appealed to some design sense of mine).

--
J C Lawrence                                 Home: claw at kanga.nu
---------(*)                               Other: coder at kanga.nu
http://www.kanga.nu/~claw/        Keys etc: finger claw at kanga.nu
--=| A man is as sane as he is dangerous to his environment |=--


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