Re: Add sub-transaction overflow status in pg_stat_activity

On Mon, Nov 14, 2022 at 10:09:57AM -0500, Robert Haas wrote:
> I think I fundamentally disagree with the idea that we should refuse
> to expose instrumentation data because some day the internals might
> change. If we accepted that argument categorically, we wouldn't have
> things like backend_xmin or backend_xid in pg_stat_activity, or wait
> events either, but we do have those things and users find them useful.
> They suck in the sense that you need to know quite a bit about how the
> internals work in order to use them to find problems, but people who
> want to support production PostgreSQL instances have to learn about
> how those internals work one way or the other because they
> demonstrably matter. It is absolutely stellar when we can say "hey, we

I originally thought having this value in pg_stat_activity was overkill,
but seeing the other internal/warning columns in that view, I think it
makes sense.  Oddly, is our 64 snapshot performance limit even
documented anywhere?  I know it is in Simon's patch I am working on.

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

  Indecision is a decision.  Inaction is an action.  Mark Batterson