It really depends what processing needs to be done on the data. You are trading space for speed. Here if you need to get all the data for a movie, you will need to go through all of the users. So before choosing a format to store the data, it might be useful to know what you want to do with it first.

In reply to Re^2: Netflix (or on handling large amounts of data efficiently in perl) by mirod
in thread Netflix (or on handling large amounts of data efficiently in perl) by Garp

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