Idiom to manage on-demand cache in Redis' set

Redis 2.0. (Solutions for 2.2 are also interesting, but, sadly, I can't upgrade yet.)

I need to store some data in Redis set:

SADD mycache apple
SADD mycache orange

This cached data would be used with SINTER commands:

SADD foo apple
SADD foo pear
... later ...
SINTER foo mycache

I want to be able to create the mycache set on-demand. That is, check if set is there when SINTER is issued, and create it if it is missing.

But I can't see how can I achieve this effectively. The only solution I see is as follows:

MULTI
EXISTS mycache
SINTER foo mycache
EXEC

...And check o开发者_StackOverflow社区n client if first command returned true. Is it the best solution available?

Or maybe I am going against the Redis "way of things"?

Well, I ended up using the solution included in the question. It works.

If you know anything better than that — please post it here.