Hmmm, it's not always that clear cut.

For example, Redis officially advised people to disable it due to a latency impact:

https://redis.io/docs/latest/operate/oss_and_stack/managemen...

Pretty sure Redis even outputs a warning to the logs upon startup when it detects hugepages are enabled.

Note that I'm not a Redis expert, I just remember this from when I ran it as a dependency for other software I was using.

1) That is about transparent huge pages which is a different thing and 2) it is always clear cut for PostgreSQL. If you can you should always use huge pages (the non-transparent kind).

That's transparent huge pages, which are also not the setting recommended for PostgreSQL.

Java can work with transparent hugepages (in addition to preallocated hugepages), but you just use +AlwaysPreTouch to map them in during the startup so that at runtime there won't be any delays or jitter. Redis should add a similar option