Re: Lifetime of commit timestamps

On Fri, Nov 17, 2023 at 04:36:44PM -0500, Bruce Momjian wrote:
> On Fri, Nov 17, 2023 at 01:20:46PM -0800, Andres Freund wrote:
> > On 2023-11-17 15:39:14 -0300, Euler Taveira wrote:
> > 
> > I think the connection between freezing and removal of commit timestamps is a
> > lot less direct that your suggested docs suggest. There can be no freezing and
> > we'll still remove timestamps (if tuples were deleted/updated). And tuples can
> > be frozen without the committs being truncated (if other tables have an older
> > relfrozenxid).
> > 
> > The relevant limiting factor is minimum of all databases datfrozenxid. Which
> > in turn is limited by relfrozenxid of each table in said database. And
> > relfrozenxid is limited by snapshots (and prepared transactions, replication
> > slots, etc).
> 
> Okay, I went with more weasel-wording in the attached patch.

Patch applied back to PG 16.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.