Re: pg_upgrade failing for 200+ million Large Objects

On Wed, Mar 27, 2024 at 10:08:26AM -0500, Nathan Bossart wrote:
> On Wed, Mar 27, 2024 at 10:54:05AM -0400, Tom Lane wrote:
>> Michael Banck <mbanck@gmx.net> writes:
>>> What is the status of this? In the commitfest, this patch is marked as
>>> "Needs Review" with Nathan as reviewer - Nathan, were you going to take
>>> another look at this or was your mail from January 12th a full review?
>> 
>> In my mind the ball is in Nathan's court.  I feel it's about
>> committable, but he might not agree.
> 
> I'll prioritize another round of review on this one.  FWIW I don't remember
> having any major concerns on a previous version of the patch set I looked
> at.

Sorry for taking so long to get back to this one.  Overall, I think the
code is in decent shape.  Nothing stands out after a couple of passes.  The
small amount of runtime improvement cited upthread is indeed a bit
disappointing, but IIUC this at least sets the stage for additional
parallelism in the future, and the memory/disk usage improvements are
nothing to sneeze at, either.

The one design point that worries me a little is the non-configurability of
--transaction-size in pg_upgrade.  I think it's fine to default it to 1,000
or something, but given how often I've had to fiddle with
max_locks_per_transaction, I'm wondering if we might regret hard-coding it.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com