Myrrix recommend vs recommendToAnonymous

Question

In Myrrix, what are the differences (mainly in terms of performance - time taken, memory) between doing a recommend query for a particular user, and doing a recommendToAnonymous query by treating that user as anonymous and feeding that user's items (suppose we have a huge optimized MySQL database with caches and bells to retrieve those) into recommendToAnonymous.

Are there any significant performance penalties with the latter, neglecting the extra DB call?

Answer 1

They are nearly identical in speed. The 'anonymous' method has to form a temporary user vector, which takes time proportional to the # of items passed, but this is quite fast. Neither uses any significant memory.

The problem with always using the anonymous method is that you would have no data actually in your model then!