No need to be so combative. Take a chill pill, zoom out and look at the reliability of the entire system and its services rather than the db in isolation. If postgres has issues, it can affect the reliability of the service further if it's also running the cache.

Besides, having the cache on separate hardware can reduce the impact on the db on spikes, which can also factor into reliability.

Having more headroom for memory and CPU can mean that you never reach the load where ot turns to service degradation on the same hw.

Obviously a purpose-built tool can perform better for a specific use-case than the swiss army knife. Which is not to diss on the latter.

> No need to be so combative.

You're confusing being "combative" with asking you to substantiate your extraordinary claims. You opted to make some outlandish and very broad sweeping statements, and when asked to provide any degree of substance, you resorted to talk about "chill pills"? What does that say about the substance if your claims?

> If postgres has issues, it can affect the reliability of the service further if it's also running the cache.

That assertion is meaningless, isn't it? I mean, isn't that the basis of any distributed systems analysis? That if a component has issues, it can affect the reliability of the whole system? Whether the component in question is Redis, Postgres, doesn't that always hold true?

> Besides, having the cache on separate hardware can reduce the impact on the db on spikes, which can also factor into reliability.

Again, isn't this assertion pointless? I mean, it holds true whether it's Postgres and Redis, doesn't it?

> Having more headroom for memory and CPU can mean that you never reach the load where ot turns to service degradation on the same hw.

Again, this claim is not specific to any specific service. It's meaningless to make this sort of claim to single out either Redis or Postgres.

> Obviously a purpose-built tool can perform better for a specific use-case than the swiss army knife. Which is not to diss on the latter.

Is it obvious, though? There is far more to life than synthetic benchmarks. In fact, the whole point of this sort of comparison is that for some scenarios a dedicated memory cache does not offer any tangible advantage over just using a vanilla RDBMS.

This reads as some naive auto enthusiasts claiming that a Formula 1 car is obviously better than a Volkswagen Golf because they read somewhere they go way faster, but in reality what they use the car for is to drive to the supermarket.