Redis as a self populating cache

Question

Can Redis be used as a self populating cache (or pull-through cache) ?

In other words, is it able to create an entry on the fly if this entry is not cached yet ?

Answer 1

Redis is just a store: you add things to it and retrieve them back again. It has no awareness of what you are using it for (caching) or knowledge of the backend it would perform lookups from, that will depend on the application handling the request and using Redis to cache.

Answer 2

Can Redis be used as a self-populating cache (or pull-through cache)?

Yes! But Redis doesn't have an implementation for self-population.

So you just have to implement it yourself and it's easy too.

1. Define a wrapper class that extends(is-a relation) a redis client(of your choice).
2. Define Factory interfaces to create objects.

3. Override necessary methods that require pull-through implementation

   3.1 If the key already exists, return it.

   3.2 Otherwise use factory interfaces to create the value, cache it and return it.

Hope this answer is generic enough for any redis client.