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From Javier Canillas <javier.canil...@gmail.com>
Subject Re: Understand eventually consistent
Date Thu, 24 Feb 2011 19:40:24 GMT
HH is some kind of write repair, so it has nothing to do with CL that is a
requirement of the operation; and it won't be used over reads.

In your example QUORUM is the same as ALL, since you only have 1 RF (only
the data holder - coordinator). If that node fails, all read / writes will
fail.

Now, on another scenario, with RF = 3 and 1 node down:

CL = QUORUM. Will work, but the coordination will mark an HH over the write
and attempt to do it for some time over the failed node. Despite this, the
operation will success for the client.
CL = ALL. Will fail.
CL = ONE. Will work. 2 HH will be sent to replicas to perform the update.

*Consider CL is the client minimum requirement over an operation to succeed*.
If the cluster can assure that value, then the operation will succeed and
returned to the client (despite some HH work needs to be done after), if not
an error response will be returned.


On Thu, Feb 24, 2011 at 4:26 PM, mcasandra <mohitanchlia@gmail.com> wrote:

>
> Does HH count towards QUORUM? Say  RF=1 and CL of W=QUORUM and one node
> that
> owns the key dies. Would subsequent write operations for that key be
> successful? I am guessing it will not succeed.
> --
> View this message in context:
> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Understand-eventually-consistent-tp6038330p6061593.html
> Sent from the cassandra-user@incubator.apache.org mailing list archive at
> Nabble.com.
>

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