incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Guy Incognito <dnd1...@gmail.com>
Subject Re: Doubts related to composite type column names/values
Date Tue, 20 Dec 2011 20:49:34 GMT
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 
>>>> <mailto: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.
>>>>
>>>
>>
>


Mime
View raw message