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From Drew Kutcharian <d...@venarc.com>
Subject Re: Any plans for read-before-write update operations in CQL3?
Date Thu, 04 Apr 2013 05:05:13 GMT
I guess it'd be safe to say that the read consistency could be the same as the consistency
of the update. But regardless, that would be a lot better than reading a value, modifying
it at the client side and then writing it back.


On Apr 3, 2013, at 7:12 PM, Edward Capriolo <edlinuxguru@gmail.com> wrote:

> Counters are currently read before write, some collection operations on List are read
before write.
> 
> 
> On Wed, Apr 3, 2013 at 9:59 PM, aaron morton <aaron@thelastpickle.com> wrote:
> I would guess not. 
> 
>> I know this goes against keeping updates idempotent, 
> There are also issues with consistency. i.e. is the read local or does it happen at the
CL level ? 
> And it makes things go slower.
> 
>>  We currently do things like this in client code, but it would be great to be able
to this on the server side to minimize the chance of race conditions.
> Sometimes you can write the plus one into a new column and then apply the changes in
the reading client thread. 
> 
> Cheers
> 
> -----------------
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
> 
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 4/04/2013, at 12:48 AM, Drew Kutcharian <drew@venarc.com> wrote:
> 
>> Hi Guys,
>> 
>> Are there any short/long term plans to support UPDATE operations that require read-before-write,
such as increment on a numeric non-counter column? 
>> i.e. 
>> 
>> UPDATE CF SET NON_COUNTER_NUMERIC_COLUMN = NON_COUNTER_NUMERIC_COLUMN + 1;
>> 
>> UPDATE CF SET STRING_COLUMN = STRING_COLUMN + "postfix";
>> 
>> etc.
>> 
>> I know this goes against keeping updates idempotent, but there are times you need
to do these kinds of operations. We currently do things like this in client code, but it would
be great to be able to this on the server side to minimize the chance of race conditions.
>> 
>> -- Drew
> 
> 


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