use Redis cache instead of in memory cache

mza

I am trying to cache the topics data on Redis instead of using in memory cache, is there a way to do that using nodeBB Redis implementation ?

<baris>

Is it possible? Yes. Is it worth doing? Probably not

You would have to override core functions like Topics.getTopicData/Topics.geetTopicsFields and write your own implementation that uses redis as a cache layer. NodeBB database layer lets you store anything you want as a key/value store.

oplik0

I think they meant the post cache - AFAIK topic data isn't cached currently.

For that all you'd need to override (or modify directly in NodeBB) is the LRU Cache which would make your changes apply to almost all caches in NodeBB (file upload limits are using a TTL cache instead, but that's probably even less worth moving somewhere else)

EDIT: note that this still isn't endorsement of actually doing this. Unless you need to run many instances of NodeBB and memory constraints mean you need to share the cache, you'll probably end up slowing things down.

<baris>

Topic data is cached in memory if you are using redis or mongodb, pretty much all calls to db.getObject and it's variants are cached. https://github.com/NodeBB/NodeBB/blob/master/src/database/mongo/hash.js#L126-L135

This is the object cache that you see in the ACP. The post cache in the ACP refers to the parsing of the content field of post objects.

<baris>

More info about the caches here https://community.nodebb.org/topic/17136/caches-used-in-nodebb

oplik0

@baris tbf that's also using cache/lru

<baris>

@oplik0 yeah that's true, if they override lru cache then it would apply to most of the caches, but again it is probably not worth it and might slow things down.