On 12 December 2016 at 18:05, Robert Haas <robertmh...@gmail.com> wrote: > On Mon, Dec 12, 2016 at 12:16 PM, Simon Riggs <si...@2ndquadrant.com> wrote: >> On 12 December 2016 at 16:52, Robert Haas <robertmh...@gmail.com> wrote: >>> On Mon, Dec 12, 2016 at 11:33 AM, Simon Riggs <si...@2ndquadrant.com> wrote: >>>> Last week I noticed that the Wait Event/Locks system doesn't correctly >>>> describe waits for tuple locks because in some cases that happens in >>>> two stages. >>> >>> Well, I replied to that email to say that I didn't agree with your >>> analysis. I think if something happens in two stages, those wait >>> events should be distinguished. The whole point here is to get >>> clarity on what the system is waiting for, and we lose that if we >>> start trying to merge together things which are at the code level >>> separate. >> >> Clarity is what we are both looking for then. > > Granted. > >> I know I am waiting for a tuple lock. You want information about all >> the lower levels. I'm good with that as long as the lower information >> is somehow recorded against the higher level task, which it wouldn't >> be in either of the cases I mention, hence why I bring it up again. > > So, I think that this may be a case where I built an apple and you are > complaining that it's not an orange. I had very clearly in mind from > the beginning of the wait event work that we were trying to expose > low-level information about what the system was doing, and I advocated > for this design as a way of doing that, I think, reasonably well. The > statement that you want information about what is going on at a higher > level is fair, but IMHO it's NOT fair to present that as a defect in > what's been committed. It was never intended to do that, at least not > by me, and I committed all of the relevant patches and had a fair > amount of involvement with the design. You may think I should have > been trying to solve a different problem and you may even be right, > but that is a separate issue from how well I did at solving the > problem I was attempting to solve.
There's too many "I"s in that para. I've not presented this as a defect, nor is there any reason to believe this post is aimed at you personally. I'm letting Hackers know that I've come across two problems and I see more. I'm good with accepting reduced scope in return for performance, but we should be allowed to discuss what limitations that imposes without rancour. -- Simon Riggs 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
