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From graham sanderson <gra...@vast.com>
Subject Question about consistency levels
Date Sun, 10 Nov 2013 06:12:24 GMT
I’m trying to be more succinct this time since no answers on my last attempt.

We are currently using 2.0.2 in test (no C* in production yet), and use (LOCAL_)QUORUM CL
on read and writes which guarantees (if successful) that we read latest data.

That said, it is highly likely that (LOCAL_)ONE would return our data since it isn’t read
for quite some time after write.

Given that we must do our best to return data, we want to see what options we have when a
quorum read fails (say 2 of 3 replicas go down with 3 replicas - note we have also seen this
issue with bugs related to CF deletion/re-creating during compaction or load causing data
corruption in which case 1 bad node can screw things up)

One option is to fall back to (LOCAL_)ONE if we detect the right exception from (LOCAL_)QUORUM
from the client side, but that obviously degrades your consistency.

That said we ONLY ever do idempotent writes, and NEVER delete. So once again I wonder if there
is a (reasonable) use case for a CL whereby you will accept the first non empty response from
any replica?
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