incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Need a little help with data model design
Date Mon, 05 Jul 2010 16:23:36 GMT
You don't want to have all the data from a single logger in a single
row b/c of the 2GB size limit.

If you have a small, static number of loggers you could create one CF
per logger and use timestamp as the row key.  Otherwise use a
composite key (logger+timestamp) as the key in a single CF.

2010/7/2 Bartosz Kołodziej <bartosz.kolodziej@gmail.com>:
> I'm new to cassandra, and I want use it to store:
> loggers = { // (super)ColumnFamily ?
>     logger1 : { // row inside super CF ?
>         timestamp1 : {
>             value : 10
>         },
>         timestamp2 : {
>             value : 12
>         }
>         (many many many more)
>     }
>     logger2 : { //logger of diffrent type (in this example it logs 3 values
> instead of 1)
>         timestamp1 : {
>             v : 300,
>             c : 123,
>             s : 12.13
>         },
>         timestamp2 : {
>             v : 300
>             c : 123
>             s : 12.13
>         }
>         (many many many more)
>     }
>     (many many many more)
> }
> the only way i will be accesing this data is:
> - example: fetch slice of data from logger2 ( start = 1278009131 (timestmap)
> , end = 1278109131 )
>      expecting sorted array of data.
> - example: fetch slice of data from (logger2 and logger10 and logger20 and
> logger1234) ( start = 1278009131 (timestmap) , end = 1278109131 )
>      expecting map of sorted arrays of data. [it is basically N queries of
> first type]
> is this right definition of above: <ColumnFamily CompareWith="TimeUUIDType"
> ColumnType="Super"
>     CompareSubcolumnsWith="BytesType" Name="loggers"/> ?
> what's the best way to model this data in cassadra (keeping in mind
> partitioning and other important stuff) ?
>
>
>



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

Mime
View raw message