I was thinking of potential issues if you rebalance the tree as an example.
I’m not certain what issues could arise as I’ve never considered a concurrent data structure that lacks some kind of synchronisation for both read and writes unless it’s immutable copy-on-write or similar. Do you happen to have references available for further research? On Tue, Jan 5, 2021 at 20:15, K. Alex Mills <k.alex.mi...@gmail.com> wrote: > On Tue, Jan 5, 2021, 6:59 PM Nathan Fisher <nfis...@junctionbox.ca> wrote: > >> Does write only locking provide read correctness? I would’ve thought >> based on the memory model it could cause issues? >> >> https://golang.org/ref/mem#tmp_2 >> > > It depends on your notion of "read correctness", specifically when you > consider each read to have occurred with respect to its concurrent writes. > Linearizability may be a weaker guarantee than you want, and that's okay. > > Linearizability requires that, for each operation, you can pick some point > between the start and end of an operation when it can be said to have > "occurred". When you consider all the operations in that order, the results > you see must be the same as a sequential execution. > > In the case I have described, we can pick a linearization point for reads > just before the last write which they passed on their way down the tree. > The reads should then see all the writes which happened prior to this point. > > This isn't the order the operations enter the root, but linearizability > doesn't care. It doesn't have an opinion on when overlapping operations > "occur" with respect to one another. > > I don't think using a happens-before relation for the program order seen > by each goroutine is going to cause a problem with respect to choosing > these linearization points, but maybe I'm missing something. > > Maybe also there is a standardized notion of read correctness that you're > referring to which I am not aware of. > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CA%2Bc2dWexae8DOR4h4M9hgCFps%3D60F7bjr%3DKGPLS3OuvTL-NN7w%40mail.gmail.com.
