On Wed, Feb 16, 2022 at 10:27 AM Peter Geoghegan <p...@bowt.ie> wrote: > True, but the most recent version where that's actually possible is > PostgreSQL 8.0, which was released in early 2005.
It just occurred to me that the main historic reason for the single user mode advice was the lack of virtual XIDs. The commit that added the xidStopLimit behavior (commit 60b2444cc3) came a couple of years before the introduction of virtual transaction IDs (in commit 295e63983d). AFAICT, the advice about single-user mode was added at a time where exceeding xidStopLimit caused the system to grind to a halt completely -- even trivial SELECTs would have failed once Postgres 8.1 crossed the xidStopLimit limit. It seems as if the advice about single user mode persisted for no great reason at all. Technically there were some remaining reasons to keep it around (like the truncation thing), but overall these secondary reasons could have been addressed much sooner if somebody had thought about it. -- Peter Geoghegan
