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From Milind Parikh <milindpar...@gmail.com>
Subject Re: Consistency model
Date Sun, 17 Apr 2011 15:24:24 GMT
William
The issue is regarding whether you will see A or B; with any guarantee of
either. The discussion implies no; until the QW is complete.

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sent from my android...please pardon occasional typos as I respond @ the
speed of thought
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On Apr 17, 2011 7:48 AM, "William Oberman" <oberman@civicscience.com> wrote:

I'm pretty new to all of this, and I'm in the process of building my mental
model of Cassandra, but I'm still feeling better about this thread. The way
I figure it:
1. I'm trying to mutate the state of a key's column from A to B from a
thread somewhere (quorum)
2. I'm trying to read the state of a key from a thread somewhere else
(quorum)

If #1 succeeds I'm guaranteed to see B. If #1 fails (with an exception) I'll
see either A or B. I think I was concerned about that, and wanted to see A
in #2 until success in #1.  But, I wanted to get to state B, and if #1
retries until guaranteed success, do I care if I set B earlier than I
expected?  I'm thinking no.

I guess in terms of distributed algorithms/reasoning about systems, I'm
feeling ok with this level of guarantee (again, given the failed write tells
the client code of the undefined state).



On Apr 17, 2011, at 10:10 AM, James Cipar <jcipar@cmu.edu> wrote:

> I'm pretty new to Cassandra, ...

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