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From aaron morton <aa...@thelastpickle.com>
Subject Re: Performance impact of static vs dynamic columns and mixing the two in the same CF
Date Tue, 05 Jun 2012 18:59:51 GMT
(I'm assuming you are talking about column values here)

> 1. Does specifying the type of a column affect performance other than the cost of validating
data as it is stored?
> e.g. does it help compaction, etc?
No. 
Validation is normally pretty light weight. 


> From my reading of the docs the advantage is that the data will be validated on write
and that the various dev tools can deserialize into a human readable form easily.
Thats about it. 

> 2. Is there any impact to mixing static and dynamic columns in the same column family?
(Follow-up question: is this far outside of the     designers' intentions and thus unsafe?)
I'm not sure what you mean by static and dynamic. 

> My mental model is that a column is just a column. It's possible to specify some metadata
about columns for validation and display but that's about it. Is there something to change
this model?
That's my model too. Exceptions are secondary indexes and any data type requirements that
CQL and associated db drivers need.

I think some people take the approach of specifying the columns in the CF definition, this
is just my personal approach. 

Cheers

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

On 6/06/2012, at 4:30 AM, Edward Sargisson wrote:

> Hi all,
> A question has come up in our team about the performance impact of static vs dynamic
columns. We'd like to ask two questions:
> 
> Quick background: We are using a custom app to write to Cassandra using Hector. Production
is Solaris and pre-prod is generally Centos. We're currently on 0.7 but will be moving to
1.1 very shortly.
> 
> 1. Does specifying the type of a column affect performance other than the cost of validating
data as it is stored?
> e.g. does it help compaction, etc?
> From my reading of the docs the advantage is that the data will be validated on write
and that the various dev tools can deserialize into a human readable form easily.
> 
> 2. Is there any impact to mixing static and dynamic columns in the same column family?
(Follow-up question: is this far outside of the     designers' intentions and thus unsafe?)
> The docs seem to indicate that the designers think of static column families and dynamic
column families and *not* a mixture of the two.
> 
> My mental model is that a column is just a column. It's possible to specify some metadata
about columns for validation and display but that's about it. Is there something to change
this model?
> 
> Thanks in advance for any comments.
> 
> Cheers,
> Edward
> 
> 
> -- 
> Edward Sargisson
> senior java developer
> Global Relay
> 
> edward.sargisson@globalrelay.net
> 
> 
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