Mongodb Memory engine vs Redis for caching the writes

Question

I have a server for processing the users' page viewing history with Mongodb.

The collections are saved like this when a user views a page

view_collection

  { "_id" : "60b212afb63a57d57a8f0006", 
    "pageId" : "gh42RzrRqYbp2Hj1y", 
    "userId" : "9Swh4jkYOPjWSgxjm", 
    "uniqueString" : "s", 
    "views" : {
        "date" : ISODate("2021-01-14T14:39:20.378+0000"), 
        "viewsCount" : NumberInt(1)
    }} 

page_collection

{"_id" : "gh42RzrRqYbp2Hj1y", "views" : NumberInt(30)  ,"lastVisitors" : ["9Swh4jkYOPjWSgxjm"]}

user_collection

    {
_id:"9Swh4jkYOPjWSgxjm",
     "statistics" : {
                "totalViewsCount" : NumberInt(1197) }
}

Everything is working fine, Except that I want to find a way to cache the operations going to database .

I've been thinking about how to use Redis to cache the writings and then periodically looping through the Redis-keys to get the results inserted into Database. (But It would be too complicated and needs lots of coding. ) Also, I found Mongodb has In-Memory Storage ,for which I might not need to re-write everything from zero and simply change some config files of mongod to get the cache-write works

Answer 1

Redis is a much less featureful data store than MongoDB. If you don't need any of the MongoDB functionality on your data, you can put it in redis for higher performance.

MongoDB in memory storage engine sounds like a premature optimization.