ios - Core Data: is there a way to properly change the persistent store at runtime? -

i have problem when trying change persistent store @ runtime. way i'm trying doing reinit of whole core data stack:

- (void)initializecoredataforstore:(nsurl *)storeurl withcompletionblock:(coredatarwcompletionblock)completionblock {     //this code needed reset core data stack before re-creating new 1      [_managedobjectcontextbackgroundqueue reset];     _managedobjectcontextbackgroundqueue = nil;     [_managedobjectcontextmainqueue reset];     _managedobjectcontextmainqueue = nil;     _managedobjectmodel = nil;     _persistentstorecoordinator = nil;     _persitentstore = nil;          //---------------end reset core data stack ---------------------          //model     self.managedobjectmodel = [nsmanagedobjectmodel mergedmodelfrombundles:nil];          self.persistentstorecoordinator = [[nspersistentstorecoordinator alloc] initwithmanagedobjectmodel:self.managedobjectmodel];      //main context     self.managedobjectcontextmainqueue = [[nsmanagedobjectcontext alloc] initwithconcurrencytype:nsmainqueueconcurrencytype];     [self.managedobjectcontextmainqueue setpersistentstorecoordinator:self.persistentstorecoordinator];          //background context     self.managedobjectcontextbackgroundqueue = [[nsmanagedobjectcontext alloc] initwithconcurrencytype:nsprivatequeueconcurrencytype];     [self.managedobjectcontextbackgroundqueue performblockandwait:^{         [self.managedobjectcontextbackgroundqueue setpersistentstorecoordinator:self.persistentstorecoordinator];     }];          dispatch_queue_t queue = null;     queue = dispatch_get_global_queue(dispatch_queue_priority_default, 0);     dispatch_async(queue, ^{         nserror *error = nil;         self.persitentstore  = [self.persistentstorecoordinator addpersistentstorewithtype:nssqlitestoretype configuration:nil url:storeurl options:nil error:&error];          dispatch_sync(dispatch_get_main_queue(), ^{             if (completionblock) {                 completionblock([error localizeddescription], nil);             }         });     }); } 

all work on background context made performblock or performblockandwait. problem that, event if reset , reinit stack, if there pending "operations" on old background context, operations not canceled, , continue execute, more this, trying execute using newly instantiated background context, has persistent store. there way cancel operations private queue associated background context(the way nsoperations can canceled on operation queue)?