PostgreSQL 19 saw an unusually high number of feature reverts during beta — around 8-10 major ones — largely because LLM-assisted code review is now catching edge cases and architectural issues that would have been discovered and fixed gradually over years in the past. A security crisis also pulled senior developers away during the critical beta review period, compressing the timeline to address problems.

• LLM-assisted code review is surfacing defects far faster than manual review ever did, creating a backlog of fixes that can't be completed in time; features written before this tool existed now face a higher quality bar retroactively.
• The "Vulnpocalypse" security event between April and August pulled experienced reviewers away during beta, delaying discovery of issues until late in the cycle when there wasn't enough time to fix them without missing the release date.
• PostgreSQL's design principle that "everything works with everything" — like features working across domains, composite types, partitions, views, and triggers in combination — creates exponential test complexity that manual testing can't handle but LLM fuzzing exposes instantly.
• The community is considering an "experimental" feature status to let complex features mature in the main tree rather than being reverted, which could have helped several of the affected features.