It really isn't, outside of some stretched definition. Nor is Postgres without third-party extensions (that come with significant issues in my experience).
> The more interesting question is not whether a system is HA-capable, it's whether the system is appropriate for the job that's required of it (given said system weaknesses & strengths, plus the specific job needs).
I used to believe this kind of thing, but I've come around to the opposite; actually rather than carefully considering the strengths and weaknesses of any given system in the context of a given job, it's a lot more efficient to have some simple heuristics that are easy to evaluate for which systems are good or bad, and avoid even considering bad systems. Of course occasionally you do need to dive into a full evaluation and pick your poison, but if a task doesn't have very specific requirements you avoid a lot of headache by just dismissing most of the possibilities out of hand.
> And my argument was that both Redis and Postgres were fine, for the job that was described.
But they're not contributing anything to the job that's described! Adding an extra moving part to the system that doesn't actually achieve anything is a much worse error than choosing the wrong system IMO.
