Multi-parameter match-finder with Redis

Question

I need to create an match-finder system for some data set, as follows:

There is a set of objects, each identified by a string ObjectID.

Each obj

Answer 1

What you are trying to do here is an inverted index.

For each column, have it map to a "set". Then, you can intersect the sets to get the result.

So, APPLE: RED ROUND FRUIT would map to the following inserts:

SADD p1:RED APPLE
SADD p2:ROUND APPLE
SADD p3:FRUIT APPLE

Then, let's say I want to query for * ROUND FRUIT, I would do:

SINTER p2:ROUND p3:FRUIT

This command is taking the intersection of the items in the p2:ROUND set and the p3:FRUIT set. This will return all the items that are ROUND and FRUIT, not caring what p1 is.

Some other examples:

SMEMBERS p1:GREEN
SINTER p1:RED p2:ROUND p3:FRUIT
SUNION p1:RED p1:GREEN

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My above answer is going to use some computation power because the intersection operation is O(N*M). Here is a way of doing it that is more memory intensive, but will have faster retrieval because it effectively precomputes the indexes.

For each combination of properties, make a key that stores a set:

So, APPLE: RED ROUND FRUIT would map to the following inserts:

SADD RED:ROUND:FRUIT APPLE
SADD :ROUND:FRUIT APPLE
SADD RED::FRUIT APPLE
SADD RED:ROUND: APPLE
SADD RED:: APPLE
SADD :ROUND: APPLE
SADD ::FRUIT APPLE
SADD ::: APPLE

Then, to query, you simply access the respective key. For example, * ROUND FRUIT would simply be

SMEMBERS :ROUND:FRUIT

Obviously, this doesn't scale well at all in terms of memory when you have many dimensions, but it will be extremely snappy to retrieve results.