feature request: xmin info

[alexitheodore]

I use pg_activity all day every day, thanks!

One feature that feels missing though is information on xid. I struggle to keep my long-running queries at bay (running a datawarehouse type db) but sometimes they happen and cause issues. Knowing what transactions are blocking vacuum based on xmin horizon stuff would be really helpful. Its not always as simple as "the oldest transaction" because that could be vacuums or replication slots OR (in my case) procedures that have transaction control built in internally.