ios - MagicalRecord with NSOperation causing persistence issues -

i'm using magicalrecord manage core data. app receives chunks of data needs iterated on individually added store records, , saved. put code nsoperation. looks this:

class addincomingmessageoperation: nsoperation {     override func main() {         let context = nsmanagedobjectcontext.mr_context()          self.message = message.createmessage(             json: self.messagejson,             context: context)         if self.message != nil {             context.mr_savetopersistentstoreandwait()         }     } } 

running on nsoperationqueue.mainqueue seems work without issue, other holding ui. next move run of these operations on own background operation queue. adding them nsoperationqueue , running them results in mixed data.

what mean - createmessage function checks existing conversation object, , adds conversation if exists, or creates 1 if doesn't. requires knowing exists in store. seems happening how, them running on background queue, they're creating conversations have been created in operation.

i can solve of setting operationqueue.maxconcurrentoperationcount = 1, slows whole thing down.

you cannot use main thread context on background thread. not in core data , not in magical record.

use mr methods designed background operations, such savewithblock. create background contexts mr_newcontext.

if make use of these simple apis, might able dispense cumbersome nsoperation subclasses.