PostgreSQL and the OOM Killer: Why You Must Use Strict Memory Overcommit

Ubicloud's PostgreSQL team recommends using strict memory overcommit settings to protect databases from catastrophic out-of-memory (OOM) kills, based on 15 years of experience operating managed PostgreSQL services. The article explains that PostgreSQL cannot tolerate sudden OOM termination and outlines a heuristic for determining the right memory overcommit limit, including a discussion of a kernel bug that temporarily forced them to disable this setting.