Memcached is meant to be a lightweight memory cache, which makes sense, but contrary to the article's claim that "Redis is brought into a stack as a cache, and it is run with the assumption that people treat it that way"—I have very very rarely experienced this. Redis is brought into a stack because (most importantly!) it's fast and (almost as importantly!) because it's simple. I don't think this article is written by AI, but (and I'm trying to be charitable here), it's just like.. dumb.
> Dealing with memcached downtime is incredibly easy, because client libraries generally ignore connection exceptions. For instance, a simple get will just return the default value (or none) if the server is down.
This is a terrible idea in the context of things that might use Redis. If you use Redis with some kind of complex state (say, a document if you're working on a Notion clone, for instance), wtf even is a "default value"? In fact, I actually also want to know when the thing is down.
> Clustering memcached is wonderful, because memcached actually has no clustering built-in.
Yeah bro, this is yet another one of the reasons people use Redis: it handles consensus and clustering for you. What even is this article? It's a master class in straw-manning architectural decisions: most people use hammers as hammers, but screwdrivers make great hammers too, especially if you also need to screw stuff in! I mean.. technically true?
> it handles consensus and clustering for you
Considering how complex and error prone this is, I don’t want it in my stack.
> Considering how complex and error prone this is, I don’t want it in my stack.
Have you ever used Redis before? I've literally never had to manage clustering or had any issues with it, and I've been using Redis for like 15 years (including for games where state had to live in multiple regions and could change on a 30- or 60-tick basis).
The memcache slab pools are a leaky abstraction that you may end up having to manage operationally, and it's another way Redis is simpler.
Agreed. Memcache is great until you get into the business of having to configure slabs. Most people just reach for redis at that point.
I always used memcached without knowing how it stores things.. never knew about the slab thing.
It is more sophisticated than grab memory per item.
This helped be to understand it better - https://vectree.io/c/memcached-internals-slab-allocation-lru...
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> wtf even is a "default value"?
The article mentions the default value is a null, which would be the cue to run whatever computationally expensive op or query the db or hit the disk etc... that you would normally run if you had no cache to begin with.
> but screwdrivers make great hammers too
I don't know what your screwdrivers look like but that sounds like a rough time.
Generally you can use the back of a screwdriver like a hammer.
It works pretty well when you need to hit something with a solid object a couple times.
Sounds like a trip to the hospital.