使用 Redis Pub/Sub 将数据持久化到 RDBMS 中

Question

I was experimenting with using Redis for caching and got a bit confused with persistence. I would like to create a service that automatically writes into a PostgreSQL database every time the Redis cache is updated.

My initial thought was to use the Pub/Sub feature to listen to events and then trigger the appropriate queries that write into my RDBMS. Though, after looking some more into the Pub/Sub feature it appears that it is probably not be meant to be used this way.

It seems that the standard practice is to keep that logic inside of the REST API that queries Redis. I would however like to have a service that automatically does this in the background. Is there a simpler way of doing this that I am missing ?

Thank you in advance.

Answer 1

I guess the common way is to Save data to MongoDB and Redis manually. for example when a user post new message:

newPost = new Post("Hello world!");

// save to db and get model ID
newPost->save();

// save model to Redis
newPost->saveToCache();

This approach will guarantee that all new Models will store in database even when Redis is down.

An other approach is to save data in Redis first, and add a flag to a Redis List , Then(anytime later) read flags from list and save related data to database.