On 28 May 2018 at 10:57, Mark Hammond <[email protected]> wrote: > On 26/05/2018 7:30 am, Bob Micheletto wrote: > >> The current production sync node configuration allows for a sync node to >> be recovered after it has been rebooted. However, memcached is completely >> cleared as a result. Also, the tabs collection is lost for good, since it >> is presently memcached only. >> > > To be clear, this would be used in cases where we'd otherwise > node-reassign all users on that node, right? > > While losing tabs isn't ideal, it's clearly an improvement over losing > everything, so it's difficult to argue that this isn't a good thing. > > As Richard says, assuming that we can ensure the clients are aware the tab > collection has been reset I think we'll recover in the same way we would > for a node reassignment. And as Richard also says, I believe simply > ensuring the lastModified time for that collection is zero will do the > right thing on Desktop and I can't imagine they could possibly do anything > different. It shouldn't be too difficult to verify. >
>From a quick look at the server code, what I expect will happen is that the "tabs" collection would be *completely missing* from /info/collections, just as if the user had never written anything into that collection. It seems reasonable that the first device to sync after a reboot, would detect that the "tabs" collection is missing and re-upload its own tabs. However, once this first device has re-uploaded and restored a sensible-looking timestamp to the "tabs" collection, what will be the behaviour of other devices? It seems like this might prevent them from discovering that their own tab data has disappeared, and they'll only recover after user navigation triggers them to upload a new modified tab record. Thom has an interesting suggestion in the meeting last week, that we could force clients into doing a full re-sync of a collection by modifing the "syncid" for that collection in their meta/global record. Would this be a more reliable (albeit more hacky!) way to guide the clients into correct behaviour here? Ryan
_______________________________________________ Sync-dev mailing list [email protected] https://mail.mozilla.org/listinfo/sync-dev
