Re: Add sub-transaction overflow status in pg_stat_activity

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Nov 14, 2022 at 12:47 PM Andres Freund <andres@anarazel.de> wrote:
>> I'd go the other way. It's pretty unimportant whether it overflowed, it's
>> important how many subtxns there are. The cases where overflowing causes real
>> problems are when there's many thousand subtxns - which one can't judge just
>> from suboverflowed alone. Nor can monitoring a boolean tell you whether you're
>> creeping closer to the danger zone.

> This is the opposite of what I believe to be true. I thought the
> problem is that once a single backend overflows the subxid array, all
> snapshots have to be created suboverflowed, and this makes visibility
> checking more expensive.

Yeah, that's what I thought too.  Andres, please enlarge ...

            regards, tom lane