[ranyefet]

My thoughts exactly.

Does Postgres still make sense for append only tables or maybe elastic or other kind of database would be more suitable?

[abraxas]

Postgres makes a lot of sense with append only tables. You can easily partition them by time (usually) and thus have an easy way to break up the index trees as well as using a cheap indexing scheme like BRIN and being able to just drop old chunks as they become irrelevant.