Well, I think I only need to lock on writes, and it'll be easier if I just lock the entire tree on writes. Reads will be the majority of the operations by far. This is for a bit of caching before we go to a K/V database like REDIS, etc.
On Tuesday, January 5, 2021 at 5:16:36 PM UTC-8 k.alex...@gmail.com wrote: > On Tue, Jan 5, 2021, 6:59 PM Nathan Fisher <nfi...@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/8d97ad06-f7e6-4fdd-8ec4-0803e0ad3dd1n%40googlegroups.com.
