Hello > As I understand it, lock group is some infrastructure that is used by > parallel queries, but could be used for something else too. So if > more documentation is needed, we should say something like "For now, > only parallel queries can have a lock group" or something like that.
If lockGroupLeader will be used in some way for non-parallel query, then the name leader_pid could be confusing. No? I treat pg_stat_activity as view for user. We have document somewhere what is "lock group leader" (excepts README in source tree)? I meant user going to read documentation, "ok, this field is process ID of the lock group leader, but what is it?". Expose a leader pid for parallel worker will be clear improvement for user. And seems lockGroupLeader->pid is exactly this stuff. Therefore, I would like to see such description and meaning of the field. > The fact that leader_pid == pid for the leader and different for the > other member should be obvious, I'm not sure that it's worth > documenting that. It may be not obvious that leader_pid is not null in this case. But ok, no objections. regards, Sergei
