Persistent caching

[Yinebeb Tariku]

Hello Gene,

I noticed that the cache layer is implemented on the persistent layer, by adding entries then removing after use from database. I am curious if there a significant advantage of using an in memory database e.g. redis. 

For reference, I am talking about PersistentCacheInterface at https://github.com/tinode/chat/blob/c0671ca62dbf6f68c3eb2afafb69cdda297c0b90/server/store/store.go#L1062

Thanks!

[Gene]

Redis would add complexity for no benefit.