Testing realm performance

Conversation.m

#import "RLMObject.h"
@class Message;

@interface Conversation : RLMObject
    
@property NSString *peerId;
@property NSDate *mostRecentDate;
@property Message *mostRecentMessage;
@end

RLM_ARRAY_TYPE(Conversation)

@implementation Conversation
    
+ (NSString *)primaryKey {
    return @"peerId";
}

@end

Message.m

#import "RLMObject.h"

@interface Message : RLMObject
    
@property NSString *Id;
@property NSString *peerId;
@property NSDate *recordingDate;
@property NSString *text;
@end

@implementation Message
    
+ (NSString *)primaryKey {
    return @"Id";
}

+ (NSArray<NSString *> *)indexedProperties {
    return @[@"peerId", @"recordingDate"];
}

@end

ViewController.m

#import "ListViewController.h"
#import <Realm/Realm.h>
#import "Message.h"
#import "Conversation.h"

@interface ListViewController ()
    
@property NSMutableArray<RLMResults *> *mResults;
@property NSMutableArray<RLMNotificationToken *> *mNotificationToken;

@property RLMRealm *realm;

@property BOOL disableSort;
@property BOOL disableInjectMessages;
@end

@implementation ListViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    _disableSort = NO;
    _disableInjectMessages = NO;
    
    _mResults = [NSMutableArray new];
    _mNotificationToken = [NSMutableArray new];

    _realm = [RLMRealm defaultRealm];
    
    [self _generateConversations];
}

#pragma mark - Actions
- (IBAction)addMessages:(id)sender {
    NSMutableArray *msgs = [NSMutableArray new];
    for (NSInteger i = 0; i < 200; i ++) {
        Message *msg = [[Message alloc] init];
        msg.Id = [NSUUID UUID].UUIDString;
        msg.text = [NSUUID UUID].UUIDString;
        msg.peerId = @"first";
        msg.recordingDate = [NSDate date];
        [msgs addObject:msg];
    }
    
    [self _saveMessages:msgs];
    
    if (_disableInjectMessages == NO) {
        [self _injectMessages:msgs];
    }
}

- (IBAction)configureMessageResults:(id)sender {
    for (NSInteger i = 0; i < 5; i ++) {
        RLMResults *res = [self _getMessagesResultsForConversationId:@"first"];
        [_mResults addObject:res];
        
        RLMNotificationToken *tok = [res addNotificationBlock:^(RLMResults * _Nullable results, RLMCollectionChange * _Nullable change, NSError * _Nullable error) {
            NSLog(@"== receive notification messages ==");
        }];
        [_mNotificationToken addObject:tok];
    }
}

#pragma mark - Inject
- (void)_injectMessages:(NSArray<Message *> *)messages {
    [_realm beginWriteTransaction];

    Conversation *conv = [Conversation objectInRealm:_realm forPrimaryKey:messages.lastObject.peerId];
    conv.mostRecentMessage = messages.lastObject;
    conv.mostRecentDate = messages.lastObject.recordingDate;

    [_realm addOrUpdateObjects:@[conv]];
    [_realm commitWriteTransaction];
}

#pragma mark - Generate
- (void)_generateConversations {
    NSMutableArray *conversations = [NSMutableArray new];
    for (NSInteger i = 0; i < 4; i ++) {
        Conversation *conv = [[Conversation alloc] init];
        NSArray *indexes = @[@"first", @"second", @"third", @"forth"];
        conv.peerId = indexes[i];
        [conversations addObject:conv];
    }
    
    [self _saveConversations:conversations];
}

#pragma mark - Storage
- (void)_saveMessages:(NSArray<Message *> *)messages {
    RLMRealm *realm = _realm;
    [realm beginWriteTransaction];
    [realm addOrUpdateObjects:messages];
    [realm commitWriteTransaction];
}

- (void)_saveConversations:(NSArray<Conversation *> *)conversations {
    RLMRealm *realm = _realm;
    [realm beginWriteTransaction];
    [realm addOrUpdateObjects:conversations];
    [realm commitWriteTransaction];
}

- (RLMResults *)_getMessagesResultsForConversationId:(NSString *)conversationId {
    RLMRealm *realm = _realm;
    NSString *filter = [NSString stringWithFormat:@"peerId == '%@'", conversationId];
    RLMResults *results = [Message objectsInRealm:realm where:filter];
    
    if (_disableSort == NO) {
        RLMSortDescriptor *sortDescr = [RLMSortDescriptor sortDescriptorWithKeyPath:@"recordingDate" ascending:NO];
        results = [results sortedResultsUsingDescriptors:@[sortDescr]];
    }
    return results;
}

@end