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Posted to user@cassandra.apache.org by Yi Yang <yy...@me.com> on 2011/08/06 01:58:47 UTC

column metadata and sstable

Dear all,

I'm wondering what's the advantage of assigning column metadata when NOT using secondary indices.

I've gone through the SSTable internal and found out it won't do such conversion.    Thus I think the only advantage we got via column metadata is a data validation type, am I correct?

Thanks.
Steve

Re: column metadata and sstable

Posted by Yi Yang <yy...@me.com>.

Thanks Aaron,

This is the same as I've thought. But I'm wondering if there's come triggers that can hash the column name in order to save disk space. Or do you think it's better to have this feature?

Best,
Steve



On Aug 6, 2011, at 7:06 PM, aaron morton wrote:

> AFAIK it just makes it easier for client API's to understand what data type to use. e.g. it can give your code a long rather than a str / byte array . 
> 
> Personally I'm on the fence about using it. It has some advantages to the client, but given the server does not really need the information it feels a little like additional coupling that's not needed . 
> 
> Cheers
> 
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 6 Aug 2011, at 11:58, Yi Yang wrote:
> 
>> Dear all,
>> 
>> I'm wondering what's the advantage of assigning column metadata when NOT using secondary indices.
>> 
>> I've gone through the SSTable internal and found out it won't do such conversion.    Thus I think the only advantage we got via column metadata is a data validation type, am I correct?
>> 
>> Thanks.
>> Steve
>

Re: column metadata and sstable

Posted by aaron morton <aa...@thelastpickle.com>.

AFAIK it just makes it easier for client API's to understand what data type to use. e.g. it can give your code a long rather than a str / byte array . 

Personally I'm on the fence about using it. It has some advantages to the client, but given the server does not really need the information it feels a little like additional coupling that's not needed . 

Cheers

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

On 6 Aug 2011, at 11:58, Yi Yang wrote:

> Dear all,
> 
> I'm wondering what's the advantage of assigning column metadata when NOT using secondary indices.
> 
> I've gone through the SSTable internal and found out it won't do such conversion.    Thus I think the only advantage we got via column metadata is a data validation type, am I correct?
> 
> Thanks.
> Steve