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From aaron morton <aa...@thelastpickle.com>
Subject Re: indexing question related to playOrm on github
Date Thu, 16 Aug 2012 02:26:55 GMT
> 1.  Can playOrm be listed on cassandra's list of ORMs?  It supports a JQL/HQL query on
a trillion rows in under 100ms (partitioning is the trick so you can JQL a partition)
No sure if we have an ORM specific page. If it's a client then feel free to add it to http://wiki.apache.org/cassandra/ClientOptions

> I was wondering if cassandra has or will ever support eventual constancy where it keeps
both the REMOVE AND the ADD together such until it is on all 3 replicated nodes and in resolving
the consistency would end up with an index that only has the very last one in the index.
Not sure I fully understand but it sounds like you want a transaction, which is not going
to happen.

Internally when Cassandra updates a secondary index it does the same thing. But it synchronises
updates around the same row so one thread will apply the changes at a time. 

Hope that helps. 
-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 16/08/2012, at 12:34 PM, "Hiller, Dean" <Dean.Hiller@nrel.gov> wrote:

> 1.  Can playOrm be listed on cassandra's list of ORMs?  It supports a JQL/HQL query on
a trillion rows in under 100ms (partitioning is the trick so you can JQL a partition)
> 2.  Many applications have a common indexing problem and I was wondering if cassandra
has or could have any support for this in the futureā€¦.
> 
> When using wide row indexes, you frequently have <indexedValue>.<primaryKey>
as the composite key.  This means when you have your object like so in the database
> 
> Activity {
>   pk: 65
>   name: bill
> }
> 
> And then two servers want to save it as
> 
> Activity {
>   pk:65
>   name:tim
> }
> Activity {
>   pk:65
>   name:mike
> }
> 
> Each server will remove <bill><65> and BOTH servers will add <tim><65>
AND <mike><65> BUT one of them will really be a lie!!!!!  I was wondering if cassandra
has or will ever support eventual constancy where it keeps both the REMOVE AND the ADD together
such until it is on all 3 replicated nodes and in resolving the consistency would end up with
an index that only has the very last one in the index.
> 
> Thanks,
> Dean
> 


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