Thanks DuyHai, I will switch to using a set. But I'm still not sure how to resolve the original question.
- Original labels = [] - Request 1 arrives with label = 1, and request 2 arrives with label = 2 - Updates are sent to c* with labels = [1] and labels = [2] simultaneously. What will happen in the above case? Will it cause the labels to end up as [1,2] (what I want) or either [1] or [2]? If I use consistency level = all, will that cause it to end up with [1,2]? On Sat, Nov 12, 2016 at 4:59 PM, DuyHai Doan <doanduy...@gmail.com> wrote: > Don't use list, use set instead. If you need ordering of insertion, use a > map<timeuuid,text> where timeuuid is generated by the client to guarantee > insertion order > > When setting a new value to a list, C* will do a read-delete-write > internally e.g. read the current list, remove all its value (by a range > tombstone) and then write the new list. Please note that prepend & append > operations on list do not require this read-delete-write and thus performs > slightly better > > On Sat, Nov 12, 2016 at 11:34 AM, Ali Akhtar <ali.rac...@gmail.com> wrote: > >> I have a table where each record contains a list<string> of labels. >> >> I have an endpoint which responds to new labels being added to a record >> by the user. >> >> Consider the following scenario: >> >> - Record X, labels = [] >> - User selects 2 labels, clicks a button, and 2 http requests are >> generated. >> - The server receives request for Label 1 and Label 2 at the same time. >> - Both requests see the labels as empty, add 1 label to the collection, >> and send it. >> - Record state as label 1 request sees it: [1], as label 2 sees it: [2] >> >> How will the above conflict be resolved? What can I do so I end up with >> [1, 2] instead of either [1] or [2] after both requests have been processed? >> > >
