You can do it in a SimpleStatement assuming you provide the CQL exactly as you provided, but in a PreparedStatement it will not work because cql prohibits provide bind values in collection literals. For it to work you could provide a List of UDT values in a bound prepared statement, i.e.:
UserType udtType = cluster.getMetadata().getKeyspace("k").getUserType("u"); UDTValue value = udtType.newValue(); value.setString(0, "data"); PreparedStatement p0 = session.prepare("UPDATE my_table SET labels = labels + ? where id = ?"); BoundStatement b0 = p0.bind(*Lists.newArrayList(value)*, 0); session.execute(b0); Thanks, Andy On Sat, Nov 12, 2016 at 9:02 AM, Ali Akhtar <ali.rac...@gmail.com> wrote: > Looks like the trick was to use [] around the udt value literal. > > Any way to do this using the java driver? > > On Sat, Nov 12, 2016 at 7:58 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: > >> Changing the double quotes to single quotes gives: >> >> UPDATE my_table SET labels = labels + {id: 'foo'} where id = ''; >> >> InvalidRequest: Error from server: code=2200 [Invalid query] >> message="Invalid user type literal for labels of type list<frozen<label>>" >> >> >> On Sat, Nov 12, 2016 at 7:50 PM, Ali Akhtar <ali.rac...@gmail.com> wrote: >> >>> The question is about appending to a set of frozen<udt> and how to do >>> that while avoiding the race condition. >>> >>> If I run: >>> >>> UPDATE my_table SET labels = labels + {id: "foo"} where id = 'xx'; >>> >>> I get: >>> >>> SyntaxException: line 1:57 no viable alternative at input '}' (...= >>> labels + {id: ["fo]o"}...) >>> >>> Here labels is set<frozen<label>> >>> >>> On Sat, Nov 12, 2016 at 7:40 PM, Vladimir Yudovin <vla...@winguzone.com> >>> wrote: >>> >>>> If I used consistency = ALL both when getting the record, and when >>>> saving the record, will that avoid the race condition? >>>> If I use consistency level = all, will that cause it to end up with >>>> [1,2]? >>>> No. Even if you have only one host it's possible that two threads first >>>> both read data and than overwrite existing value one by one. >>>> >>>> The list is actually of a list<frozen<my_udt>> and not a text (I used >>>> text for simplification, apologies). >>>> In that case, will updates still merge the list values instead of >>>> overwriting them? >>>> Do you mean UPDATE cql operation? Yes, it adds new values to list, >>>> allowing duplicates. >>>> >>>> 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. >>>> As I mentioned duplicates are allowed in LIST, and as DOC says: >>>> >>>> These update operations are implemented internally without any >>>> read-before-write. Appending and prepending a new element to the list >>>> writes only the new element. >>>> >>>> Only when using index >>>> >>>> When you add an element at a particular position, Cassandra reads the >>>> entire list, and then writes only the updated element. Consequently, adding >>>> an element at a particular position results in greater latency than >>>> appending or prefixing an element to a list. >>>> >>>> >>>> Best regards, Vladimir Yudovin, >>>> >>>> *Winguzone <https://winguzone.com?from=list> - Hosted Cloud >>>> CassandraLaunch your cluster in minutes.* >>>> >>>> >>>> ---- On Sat, 12 Nov 2016 07:57:36 -0500*Ali Akhtar >>>> <ali.rac...@gmail.com <ali.rac...@gmail.com>>* wrote ---- >>>> >>>> The labels collection is of the type set<frozen<label>> , where label >>>> is a udt containing: id, name, description , all text fields. >>>> >>>> On Sat, Nov 12, 2016 at 5:54 PM, Ali Akhtar <ali.rac...@gmail.com> >>>> wrote: >>>> >>>> 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? >>>> >>>> >>>> >>> >> >