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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Not all data structures need timestamps (and don't require wasted memory).
Date Sun, 04 Sep 2011 03:53:44 GMT
I strongly suspect that you're optimizing prematurely.  What evidence
do you have that timestamps are producing unacceptable overhead for
your workload?  You do realize that the sparse data model means that
we spend a lot more than 8 bytes storing column names in-line with
each column too, right?

If disk space is really the limiting factor for your workload, I would
recommend testing the compression code in trunk.  That will get you a
lot farther than adding extra options for a very niche scenario.

On Sat, Sep 3, 2011 at 10:26 PM, Kevin Burton <burton@spinn3r.com> wrote:
> Sure….. I'm willing to concede that Cassandra isn't for anyone but why make
> it worse than it has to be?
> Why 8 bytes?  Why not 64 bytes?
> I imagine even in your situation a 8x boost in storage would not be nice ;)
> The point is that replication in Cassandra only needs timestamps to handle
> out of order writes … for values that are idempotent, this isn't necessary.
>  The order doesn't matter.
> Adding support for Cassandra to support variable width resolution (1ms is
> probably too high for most uses) and to turn timestamps off on a per
> tablespace basis could be really handy.
> Kevin
> On Sat, Sep 3, 2011 at 7:56 PM, Stephen Connolly
> <stephen.alan.connolly@gmail.com> wrote:
>>
>> maybe not all nosql applications fit cassandra.
>>
>> the whole core logic of how cassandra is eventually consistent is because
>> of the per column timestamps... if they are a pain for you consider storing
>> eg as a small number of fat columns rather than many skinny ones... either
>> that or look at a different database for your use case. ;-)
>>
>> - Stephen
>>
>> ---
>> Sent from my Android phone, so random spelling mistakes, random nonsense
>> words and other nonsense are a direct result of using swype to type on the
>> screen
>>
>> On 3 Sep 2011 16:01, "Kevin Burton" <burton@spinn3r.com> wrote:
>
>
>
> --
>
> Founder/CEO Spinn3r.com
>
> Location: San Francisco, CA
> Skype: burtonator
>
> Skype-in: (415) 871-0687
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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