if you have a relatively small, static set of subcolumns, that you
read as a group, then using supercolumns is reasonable
On Tue, Jun 1, 2010 at 7:33 PM, Peter Hsu <pe...@motivecast.com> wrote:
> I have a pretty simple data modeling question. I don't know whether or not
> to use a CF or SCF in one instance.
>
> Here's my example. I have an Store entry and locations for each store. So I
> have something like:
>
> Using CF:
> Store { //CF
> storeId { //row key
> storeName:str,
> storeLogo:image
> }
> storeId:locationId1 {
> locationName:str,
> latLong:coordinate
> }
> storeId:locationId2 {
> locationName:str,
> latLong:coordinate
> }
> }
>
> Using SCF:
> Store { //SCF
> storeId { //row key
> store {
> storeName:str,
> storeLogo:image
> }
> locationId1 {
> locationName:str,
> latLong:coordinate
> }
> locationId2 {
> locationName:str,
> latLong:coordinate
> }
> }
> }
>
> Queries:
>
> Reads:
> 1. Read store and all locations (could be done by range query efficiently
> when using CF, since I'm using OPP)
> 2. Read only a particular location of a store (don't need the store meta
> data here)
> 3. Read only store name info (don't need any location info here)
>
> Writes:
> 1. Update store meta data (without touching location info)
> 2. Update location data for a store (without touching rest of store data)
> 3. Add a new location to an existing store (would have a unique identifier
> for location, no worries about having to do a read..)
>
> I read that SuperColumns are not as fast as Columns, and obviously you can't
> have indexed subcolumns of supercolumns, but in this case I don't need the
> subsubcolumn indices. It seems cleaner to model it as a SuperColumn, but why
> would I want to pay a performance penalty instead of just concating my keys.
>
> This seems like a fairly common pattern? What's the rule to decide between
> CF and SCF?
>
> Thanks,
> Peter
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com
