David Rowley wrote: > I've not looked into the feasibility of it, but if it were also possible to > have a "waiting_for" column which would store the process ID of the process > that's holding a lock that this process is waiting on, then it would be > possible for some smart guy to write some code which draws beautiful > graphs, perhaps in Pg Admin 4 of which processes are blocking other > processes. I imagine this as a chart with an icon for each process. > Processes waiting on locks being released would have an arrow pointing to > their blocking process, if we clicked on that blocking process we could see > the query that it's running and various other properties that are existing > columns in pg_stat_activity.
I think this is already possible, is it not? You just have to look for an identically-identified pg_locks entry with granted=true. That gives you a PID and vxid/xid. You can self-join pg_locks with that, and join to pg_stat_activity. I remember we discussed having a layer of system views on top of pg_stat_activity and pg_locks, probably defined recursively, that would show the full graph of waiters/lockers. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
