On Mon, Nov 14, 2022 at 11:35 AM Amit Singh <amitksingh.mumbai@gmail.com> wrote: > Making the information available in pg_stat_activity makes it a lot easier to identify the pid which has caused the subtran overflow. Debugging through the app code can be an endless exercise and logging every statement in postgresql logs is not practical either. If the overhead of fetching the information isn't too big, I think we should consider the subtransaction_count and is_overflowed field as potential candidates for the enhancement of pg_stat_activity.
The overhead of fetching the information is not large, but Justin is concerned about the effect on the display width. I feel that's kind of a lost cause because it's so wide already anyway, but I don't see a reason why we need *two* new columns. Can't we get by with just one? It could be overflowed true/false, or it could be the number of subtransaction XIDs but with NULL instead if overflowed.
Do you have a view on this point?
NULL when overflowed seems like the opposite of the desired effect, calling attention to the exceptional status. Make it a text column and write "overflow" or "###" as appropriate. Anyone using the column is going to end up wanting to special-case overflow anyway and number-to-text conversion aside from overflow is simple enough if a number, and not just a display label, is needed.
