objective c - CKQueryOperation working with big batch -

i have problem creating ckquery operation big batch of data. query works 100 results after more results query fail, because 1 thread bad dispatched or (libdispatch.dylib`dispatch_group_leave: ) lost... idea?

+ (void) fetchanswerswithrecordid:(ckrecordid *)recordid completionhandler:(cloudkitcompletionhandler)handler { nspredicate *predicate = [nspredicate predicatewithformat:@"ansrecordid == %@", recordid]; ckquery *query = [[ckquery alloc] initwithrecordtype:ckanswers predicate:predicate];  ckqueryoperation *operation = [[ckqueryoperation alloc] initwithquery:query]; ckqueryoperation * __weak weakself = operation; operation.resultslimit = 300; nsmutablearray *tmp = [[nsmutablearray alloc] init];   operation.recordfetchedblock = ^(ckrecord *record) {     [tmp addobject:record]; };  operation.querycompletionblock = ^(ckquerycursor *cursor, nserror *error) {     if (!handler)         return;      nsarray *array = [nsarray arraywitharray:tmp];     if(cursor != nil) {         ckqueryoperation *newoperation = [[ckqueryoperation alloc] initwithcursor:cursor];         newoperation.recordfetchedblock = weakself.recordfetchedblock;         newoperation.completionblock = weakself.completionblock;         [[self publicclouddatabase] addoperation:newoperation];     } else {         nslog(@"results: %lu", [array count]);         dispatch_async(dispatch_get_main_queue(), ^{             handler(array, error);         });     } };  [[self publicclouddatabase] addoperation:operation];} 

i think issue lies __weak operation , way create operation inside operation. here example (in swift) of how similar i.e. additional results, in fetch , not query. note use of instance variable initialize first time , use of semi-recursion through gcd dispatch_aync:

private func _fetchrecordchangesfromcloud() {     if !_fetching {         // first , time code called in gcd recusion          // clean caches use collect results of fetch         // can save record in correct order references can created         _fetchedmodifiedrecords = []         _fetcheddeletedrecordids = []          // mark fetching has started         _fetching = true     }      let operation = ckfetchrecordchangesoperation(recordzoneid: _customrecordzoneid, previousserverchangetoken: _serverchangetoken)      operation.recordchangedblock = { (record: ckrecord?) in         if let record = record {             println("received record save: \(record)")             self._fetchedmodifiedrecords.append(record)         }     }      operation.recordwithidwasdeletedblock = { (recordid: ckrecordid?) in         if let recordid = recordid {             println("received recordid delete: \(recordid)")             self._fetcheddeletedrecordids.append(recordid)         }     }      operation.fetchrecordchangescompletionblock = {         (serverchangetoken: ckserverchangetoken?, clientchangetoken: nsdata?, error: nserror?) -> void in          if let error = error {             println("error in fetching record changes: \(error)")             // try again next sync             self._fetchafternextsuccessfullsync = true             self._fetching = false             return         }          // fetched records successfuly         println("fetched records successfuly")          if let serverchangetoken = serverchangetoken {             self._serverchangetoken = serverchangetoken         }          if operation.morecoming {             // need create operation object , again             dispatch_async(dispatch_get_global_queue(dispatch_queue_priority_default, 0)) {                 self._fetchrecordchangesfromcloud()             }         } else {             // done              // process fetched records             self._processfetchedrecords()              // save changes persistent store             self._savebackgroundcontext()              // done             self._fetching = false         }     }      self._privatedatabase.addoperation(operation) }