Re: Lifetime of commit timestamps

On Mon, Nov 13, 2023, at 9:47 PM, Bruce Momjian wrote:

I think so. AFAICS nothing changed. Unless you read the source code, it is not

clear that VACUUM removes the information for frozen tuples. They are decoupled

(but executed in the same routine for convenience), hence, someone can ask why

the pg_xact_commit_timestamp() returns NULL for a transaction that was executed

*after* you enable track_commit_timestamp. The answer is the design used a

existing mechanism to clean up data in order to avoid creating a new one.