On Thu, Jul 16, 2020, 5:23 AM evdubs <[email protected]> wrote: > Do you think you'll need to try to identify the order that the events were > created in? > > What if user A does: > > $ touch file.txt > $ rm file.txt > > And what if user A had separately done: > > $ rm file.txt > Error: file not found > $ touch file.txt >
You meant for those to be user A and user B, right? > Would those operations both potentially create File-Create P H1 ; > File-Delete P H1 events when things are allowed to be out of order? Don't > they result in different states for the filesystem? If you also sent along > the time of the operation (or maybe some sequence number), won't that let > you keep things ordered and not make decisions that might be ambiguous? > Fair question. Yes, time will be sent along with the message. I was trying to boil things down as far as possible and perhaps I boiled too long. Of course, that raises its own issues about different timezones etc, but those are separate from the issue at hand. To answer your specific question: That sequence of events results in a conflict that will be flagged for human review. On Wednesday, July 15, 2020 at 10:29:36 PM UTC-10 [email protected] wrote: > >> tl;dr >> Can anyone recommend a data structure that is ordered and supports >> efficient reordering, insertion at arbitrary location, and deletion? >> >> Long form: >> >> I'm working on an operation-log reconciliation problem, where each >> operation is one of: >> >> File-Create P H >> File-Update P H >> File-Delete P H >> Folder-Create P >> Folder-Delete P >> >> P = path >> H = hash of the file (e.g. md5) >> >> Operation messages travel over the network, meaning that they could >> arrive out of order. (They could also be missed entirely, but that's a >> separate problem that I'm not working on yet.) >> >> Specifically, I want to be able to take a series of messages and collapse >> them where appropriate. For example: >> >> File-Update P H1 -> H2 >> File-Create P1 H1 >> Result after collapse: >> '(File-Create P1 H2) >> >> File-Create P H1 >> File-Delete P H1 >> Result after collapse: >> '() >> >> File-Delete P X >> File-Create P X >> Result after collapse: >> '() >> >> File-Delete P1 H1 >> File-Create P2 H2 >> File-Create P1 H1 >> Result after collapse: >> '(File-Create P2 H2) >> >> I've been mulling over various ways to handle all of this and digging >> around to find examples of other people doing it, but I'm wondering if >> there's a data structure or existing algorithm that will handle it >> cleanly. Does anyone know of such a thing? >> > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/f03b33d8-e286-4cc2-afa5-4aefd0050bd5n%40googlegroups.com > <https://groups.google.com/d/msgid/racket-users/f03b33d8-e286-4cc2-afa5-4aefd0050bd5n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAE8gKofT_R%3D-d8QEinouq8id16f7WJE2jpn5SE%2BqXPCgmODaXw%40mail.gmail.com.
