cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Kant Kodali <k...@peernova.com>
Subject Re: quick question
Date Wed, 01 Feb 2017 12:39:21 GMT
What is the difference between accepting a value and committing a value?



On Wed, Feb 1, 2017 at 4:25 AM, Kant Kodali <kant@peernova.com> wrote:

> Hi,
>
> Thanks for the response. I finished watching this video but I still got
> few questions.
>
> 1) The speaker seems to suggest that there are different consistency
> levels being used in different phases of paxos protocol. If so, what is
> right consistency level to set on these phases?
>
> 2) Right now, we just set consistency level as QUORUM at the global level
> and I dont think we ever change it so in this case what would be the
> consistency levels being used in different phases.
>
> 3) The fact that one should think about reading before the commit phase or
> after the commit phase (but not any other phase) sounds like there is
> something special about commit phase and what is that? when I set the
> QUORUM level consistency at global level Does the commit phase happen right
> after accept  phase or no? or irrespective of the consistency level when
> does the commit phase happen anyway? and what happens during the commit
> phase?
>
>
> Thanks,
> kant
>
>
> On Wed, Feb 1, 2017 at 3:30 AM, Alain RODRIGUEZ <arodrime@gmail.com>
> wrote:
>
>> Hi,
>>
>> I believe that this talk from Christopher Batey at the Cassandra Summit
>> 2016 might answer most of your questions around LWT:
>> https://www.youtube.com/watch?v=wcxQM3ZN20c
>>
>> He explains a lot of stuff including consistency considerations. My
>> understanding is that the quorum read can only see the data written using
>> LWT after the commit phase. A SERIAL Read would see it (video, around
>> 23:40).
>>
>> Here are the slides as well: http://fr.slideshare.net
>> /DataStax/light-weight-transactions-under-stress-christopher
>> -batey-the-last-pickle-cassandra-summit-2016
>>
>> Let us know if you still have questions after watching this (about 35
>> minutes).
>>
>> C*heers,
>> -----------------------
>> Alain Rodriguez - @arodream - alain@thelastpickle.com
>> France
>>
>> The Last Pickle - Apache Cassandra Consulting
>> http://www.thelastpickle.com
>>
>> 2017-02-01 10:57 GMT+01:00 Kant Kodali <kant@peernova.com>:
>>
>>> When you initiate a LWT(write) and do a QUORUM read is there a chance
>>> that one might not see the LWT write ? If so, can someone explain a bit
>>> more?
>>>
>>> Thanks!
>>>
>>
>>
>

Mime
View raw message