I wrote: > That seems like a fairly bad idea: it will add extra contention > on ProcArrayLock, and I see no real strong argument that the path > can't get traversed often enough for that to matter. It would > likely be better for KnownAssignedXidsCompress to obtain the lock > for itself, only after it knows there is something worth doing.
Since we're running out of time in the current commitfest, I went ahead and changed that, and made the cosmetic fixes I wanted, and pushed. regards, tom lane