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From Robert Coli <rc...@eventbrite.com>
Subject Re: Adding Nodes With Inconsistent Data
Date Mon, 29 Jun 2015 18:43:13 GMT
On Sun, Jun 28, 2015 at 10:46 AM, Anuj Wadehra <anujw_2003@yahoo.co.in>
wrote:

> Thanks Jake!! But I think most people have 2.0.x in Production right now
> as 2.1.6 is very recently declared Production Ready. I think the bug is too
> important to be left open in 2.0.x as it leads to data loss. Should I open
> JIRA?
>

Sorry, but this is the bug that provides very strong support to the Coli
Conjecture :

"Anyone who is storing their data in Cassandra[1] probably doesn't actually
care about consistency, even if they think they do."

This bug has existed in every version of Cassandra ever. People have run
these versions of Cassandra in production, with many many of them not
regularly running repair once every gc_grace_seconds.

Few to none of them have ever detected any problem which resulted from the
lack of consistency which must occur in an unrepaired cluster with
CASSANDRA-2434. I am forced to conclude from this data that resolving
CASSANDRA-2434 is actually not that important.

Yes, this is a surprising and somewhat troubling formulation. But if you
think about it, from the perspective of the application, a failed
non-idempotent write which nonetheless is persisted is also fatal to
consistency...

=Rob
 [1] Cassandra is cited, but this is likely more of a statement about
distribution-appropriate applications, not Cassandra specifically...

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