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From aaron morton <aa...@thelastpickle.com>
Subject Re: Doubts related to composite type column names/values
Date Wed, 21 Dec 2011 00:24:21 GMT
+1 use them if you can. 

Also you can reverse the sort order on components in the type, that can make some common queries
faster. 

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

On 21/12/2011, at 9:49 AM, Guy Incognito wrote:

> afaik composite lets you do sorting in a way that would be difficult/impossible with
string concatenation.
> 
> eg <String, Integer> with the string ascending, and the integer descending.
> 
> if i had composites available (which i don't b/c we are on 0.7), i would use them over
string concatenation.  string concatenation is a pain.
> 
> On 20/12/2011 20:33, Maxim Potekhin wrote:
>> 
>> Thank you Aaron! As long as I have plain strings, would you say that I would do almost
as well with catenation?
>> 
>> Of course I realize that mixed types are a very different case where the composite
is very useful.
>> 
>> Thanks
>> 
>> Maxim
>> 
>> 
>> On 12/20/2011 2:44 PM, aaron morton wrote:
>>> 
>>> Component values are compared in a type aware fashion, an Integer is an Integer.
Not a 10 character zero padded string. 
>>> 
>>> You can also slice on the components. Just like with string concat, but nicer.
 . e.g. If you app is storing comments for a thing, and the column names have the form <comment_id,
field> or  <Integer, String> you can slice for all properties of a comment or all
properties for comments between two comment_id's
>>> 
>>> Finally, the client library knows what's going on. 
>>> 
>>> Hope that helps.
>>> 
>>> -----------------
>>> Aaron Morton
>>> Freelance Developer
>>> @aaronmorton
>>> http://www.thelastpickle.com
>>> 
>>> On 21/12/2011, at 7:43 AM, Maxim Potekhin wrote:
>>> 
>>>> With regards to static, what are major benefits as it compares with
>>>> string catenation (with some convenient separator inserted)?
>>>> 
>>>> Thanks
>>>> 
>>>> Maxim
>>>> 
>>>> 
>>>> On 12/20/2011 1:39 PM, Richard Low wrote:
>>>>> On Tue, Dec 20, 2011 at 5:28 PM, Ertio Lew<ertiop93@gmail.com>
 wrote:
>>>>>> With regard to the composite columns stuff in Cassandra, I have the
>>>>>> following doubts :
>>>>>> 
>>>>>> 1. What is the storage overhead of the composite type column names/values,
>>>>> The values are the same.  For each dimension, there is 3 bytes overhead.
>>>>> 
>>>>>> 2. what exactly is the difference between the DynamicComposite and
Static
>>>>>> Composite ?
>>>>> Static composite type has the types of each dimension specified in the
>>>>> column family definition, so all names within that column family have
>>>>> the same type.  Dynamic composite type lets you specify the type for
>>>>> each column, so they can be different.  There is extra storage
>>>>> overhead for this and care must be taken to ensure all column names
>>>>> remain comparable.
>>>>> 
>>>> 
>>> 
>> 
> 


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