Evan, You can watch the video presentation at Facebook from http://code.google.com/p/the-cassandra-project/ (follow the link on the right). The presentation talks about the schema used by FB for email search.
Jun IBM Almaden Research Center K55/B1, 650 Harry Road, San Jose, CA 95120-6099 [email protected] Evan Weaver <[email protected] > To Sent by: [email protected] [email protected] cc Subject 05/19/2009 09:49 Re: schema example AM Please respond to cassandra-u...@in cubator.apache.or g Even if it's not actually in real-life use, some examples for common domains would really help clarify things. * blog * email storage * search index etc. Evan On Mon, May 18, 2009 at 8:19 PM, Jonathan Ellis <[email protected]> wrote: > Does anyone have a simple app schema they can share? > > I can't share the one for our main app. But we do need an example > here. A real one would be nice if we can find one. > > I checked App Engine. They don't have a whole lot of examples either. > They do have a really simple one: > http://code.google.com/appengine/docs/python/gettingstarted/usingdatastore.html > > The most important thing in Cassandra modeling is choosing a good key, > since that is what most of your lookups will be by. Keys are also how > Cassandra scales -- Cassandra can handle effectively infinite keys > (given enough nodes obviously) but only thousands to millions of > columns per key/CF (depending on what API calls you use -- Jun is > adding one now that does not deseriailze everything in the whole CF > into memory. The rest will need to follow this model eventually too). > > For this guestbook I think the choice is obvious: use the name as the > key, and have a single simple CF for the messages. Each column will > be a message (you can even use the mandatory timestamp field as part > of your user-visible data. win!). You get the list (or page) of > users with get_key_range and then their messages with get_slice. > > <ColumnFamily ColumnSort="Name" Name="Message"/> > > Anyone got another one for pedagogical purposes? > > -Jonathan > -- Evan Weaver
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