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From Sean Owen <>
Subject Re: DataModel
Date Wed, 06 Oct 2010 16:09:01 GMT
In general, if you want real-time recommendations, you want the data in
memory. Otherwise it's too slow. The JDBC-backed model works for, roughly,
small problems up to a couple million ratings. Beyond that, stick it in
memory. (And past about 100M ratings, you need to consider distributing the

FileDataModel is also in-memory since it uses GenericDataModel inside. It's
built for fine-grained updates  with its "delta files" support.

On Wed, Oct 6, 2010 at 3:57 PM, James James <>wrote:

> Hi,
> I was evaluating which DataModel should be used when we are dealing with a
> large
> amount of user data with new data coming in on a regular basis (for example
> on a
> daily basis). The GenericModel is immutable, which requires the user data
> to be
> reloaded when new data comes in. I have not tried JDBCDataModel yet. Based
> on
> the posts here, it seems to me the reloading is not needed for
> JDBCDataModel
> since it is always kept up-to-date.
> Do you think that JDBCDataModel is more efficient for my case? Are there
> any
> implementations of  DataModel using HBase?
> Thanks,
> James

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