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From aaron morton <aa...@thelastpickle.com>
Subject Re: other questions about // RE: batch_mutate
Date Tue, 26 Mar 2013 20:27:53 GMT
> a) does it treat them as N independent requests to replicas, or
This
Cheers

-----------------
Aaron Morton
Freelance Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 26/03/2013, at 5:50 AM, DE VITO Dominique <dominique.devito@thalesgroup.com> wrote:

> When the coordinator node receives a batch_mutate with different N row keys (for different
CF) :
>  
> a) does it treat them as N independent requests to replicas, or
>  
> b) does the coordinator node split the the initial batch_mutate into M batch_mutate (M
<= N) according to rowkeys ?
>  
> Thanks,
> Dominique
>  
>  
> De : aaron morton [mailto:aaron@thelastpickle.com] 
> Envoyé : vendredi 6 juillet 2012 01:21
> À : user@cassandra.apache.org
> Objet : Re: batch_mutate
>  
> Does it mean that the popular use case is when we need to update multiple column families
using the same key?
> Yes. 
>  
> Shouldn’t we design our space in such a way that those columns live in the same column
family?
> Design a model where the data for common queries is stored in one row+cf. You can also
take into consideration the workload. e.g. things are are updated frequently often live together,
things that are updated infrequently often live together.
>  
> cheers
>  
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
>  
> On 6/07/2012, at 3:16 AM, Leonid Ilyevsky wrote:
> 
> 
> I actually found an answer to my first question at http://wiki.apache.org/cassandra/API.
So I got it wrong: actually the outer key is the key in the table, and the inner key is the
table name (this was somewhat counter-intuitive). Does it mean that the popular use case is
when we need to update multiple column families using the same key? Shouldn’t we design
our space in such a way that those columns live in the same column family?
>  
> From: Leonid Ilyevsky [mailto:lilyevsky@mooncapital.com] 
> Sent: Thursday, July 05, 2012 10:39 AM
> To: 'user@cassandra.apache.org'
> Subject: batch_mutate
>  
> My current way of inserting rows one by one is too slow (I use cql3 prepared statements)
, so I want to try batch_mutate.
>  
> Could anybody give me more details about the interface? In the javadoc it says:
>  
> public voidbatch_mutate(java.util.Map<java.nio.ByteBuffer,java.util.Map<java.lang.String,java.util.List<Mutation>>>
mutation_map,
>                          ConsistencyLevel consistency_level)
>                   throws InvalidRequestException,
>                          UnavailableException,
>                          TimedOutException,
>                          org.apache.thrift.TException
> Description copied from interface: Cassandra.Iface
> Mutate many columns or super columns for many row keys. See also: Mutation. mutation_map
maps key to column family to a list of Mutation objects to take place at that scope. *
>  
>  
> I need to understand the meaning of the elements of mutation_map parameter.
> My guess is, the key in the outer map is columnfamily name, is this correct?
> The key in the inner map is, probably, a key to the columnfamily (it is somewhat confusing
that it is String while the outer key is ByteBuffer, I wonder what is the rational). If this
is correct, how should I do it if my key is a composite one. Does anybody have an example?
>  
> Thanks,
>  
> Leonid
>  
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>  
> This email, along with any attachments, is confidential and may be legally privileged
or otherwise protected from disclosure. Any unauthorized dissemination, copying or use of
the contents of this email is strictly prohibited and may be in violation of law. If you are
not the intended recipient, any disclosure, copying, forwarding or distribution of this email
is strictly prohibited and this email and any attachments should be deleted immediately. This
email and any attachments do not constitute an offer to sell or a solicitation of an offer
to purchase any interest in any investment vehicle sponsored by Moon Capital Management LP
(“Moon Capital”). Moon Capital does not provide legal, accounting or tax advice. Any statement
regarding legal, accounting or tax matters was not intended or written to be relied upon by
any person as advice. Moon Capital does not waive confidentiality or privilege as a result
of this email.
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