The problem isn't just the update / insert though, right? Don't frozen entities get overwritten completely? So if I had [1] [2] being written as updates, won't each update overwrite the set completely, so i'll end up with either one of them instead of [1,2]?
On Sat, Nov 12, 2016 at 5:50 PM, DuyHai Doan <doanduy...@gmail.com> wrote: > Maybe you should use my Achilles mapper, which does generates UPDATE > statements on collections and not only INSERT > Le 12 nov. 2016 13:08, "Ali Akhtar" <ali.rac...@gmail.com> a écrit : > >> I am using the Java Cassandra mapper for all of these cases, so my code >> looks like this: >> >> Item myItem = myaccessor.get( itemId ); >> Mapper<Item> mapper = mappingManager.create( Item.class ); >> >> myItem.labels.add( newLabel ); >> mapper.save( myItem ); >> >> On Sat, Nov 12, 2016 at 5:06 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: >> >>> 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? >>>>> >>>> >>>> >>> >>
