incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ramzi Rabah <rra...@playdom.com>
Subject Re: why does remove need a timestamp?
Date Mon, 09 Nov 2009 16:46:13 GMT
Makes lots of sense.
It would be nice to update the API wiki for remove:
http://wiki.apache.org/cassandra/API

with these details, since the current wording is potentially vague and
misleading.

Thanks guys
Ray

On Mon, Nov 9, 2009 at 2:43 AM, Mark Robson <markxr@gmail.com> wrote:
>
>
> 2009/11/9 Ramzi Rabah <rrabah@playdom.com>
>>
>> Hello all:
>> I am confused about the need of passing a  timestamp for the remove
>> operation. Why does the remove operation in Cassandra require a
>> timestamp? What happens if I provide a remove call with a different
>> timestamp than what I inserted, will the row still be deleted?
>
> It is so that if the commands are replayed in a different order on different
> nodes, the same result is produced.
>
> Remove only removes values which have a timestamp of before or the same as
> the one provided - this is essential, as if a "later" insert "overtakes" the
> remove, the remove needs to avoid removing "newer" data.
>
> The eventual consistency model only works (i.e. only produces consistency)
> if mutations have the same effect regardless of the order they are applied
> in.
>
> That is my understanding anyway.
>
> Mark
>

Mime
View raw message