Read consistency

[Arko Provo Mukherjee <ar...@gmail.com>]

Hello,

I am designing a system where for a situation, I need to have SERIAL
consistency during writes.

I understand that if the write was with QUORUM, a Read with QUORUM would
have fetched me the correct (most recent) data.

My question is what is the minimum consistency level required for read,
when my write consistency is SERIAL.

Any pointers would be much appreciated.

Thanks & regards
Arko

Re: Read consistency

[Robert Coli <rc...@eventbrite.com>]

On Tue, Mar 15, 2016 at 6:43 PM, Arko Provo Mukherjee <
arkoprovomukherjee@gmail.com> wrote:

> I am designing a system where for a situation, I need to have SERIAL
> consistency during writes.
>

Be sure to understand the implications of :

https://issues.apache.org/jira/browse/CASSANDRA-9328

=Rob

Re: Read consistency

[Alain RODRIGUEZ <ar...@gmail.com>]

Hi Arko,

Never used that consistency level so far, but here is some information:
http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_tunable_consistency_c.html

Cassandra 2.0 uses the Paxos consensus protocol, which resembles 2-phase
> commit, to support linearizable consistency. All operations are
> *quorum-based* and updates will incur a performance hit, effectively a
> degradation to one-third of normal. For in-depth information about this new
> consistency level, see the article,*Lightweight transactions in Cassandra*
> <http://www.datastax.com/dev/blog/lightweight-transactions-in-cassandra-2-0>
> .


 So it appears that a read using quorum should be fine (remember to use
local consistency level on a multi-DC environment if this is what you want
to do).

Never checked that on my own, just read that, fwiw.

C*heers,
-----------------------
Alain Rodriguez - alain@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http://www.thelastpickle.com

2016-03-16 2:43 GMT+01:00 Arko Provo Mukherjee <arkoprovomukherjee@gmail.com
>:

> Hello,
>
> I am designing a system where for a situation, I need to have SERIAL
> consistency during writes.
>
> I understand that if the write was with QUORUM, a Read with QUORUM would
> have fetched me the correct (most recent) data.
>
> My question is what is the minimum consistency level required for read,
> when my write consistency is SERIAL.
>
> Any pointers would be much appreciated.
>
> Thanks & regards
> Arko
>
>