CommitFest (commonly abbreviated to
CF) is a period of usually around one month focussed on reviewing patches for the next major PostgreSQL version.
The purpose of a CommitFest is to provide systematic, regular review of submitted patches, to avoid build-up of unreviewed patches towards the end of a development cycle.
CommitFests are typically held on odd-numbered months, with a break between March and July, as the next major release is being finalized around that time.
The concept of a CommitFest was introduced for PostgreSQL 8.4 development, as it had become clear that the previous system of ad-hoc patch submission was no longer manageable and had lead to serious delays in the release of PostgreSQL 8.3.
The PostgreSQL wiki entry PostgreSQL 8.4 Development Plan documents the rationale behind the introduction of CommitFests and links to the first series thereof, which were initially administered via Wiki pages.