When I set the option parameter to OSLogEnumeratorReverse, the iteration order of OSLogEnumerator is still from front to back in time When I set the options parameter to 0 and the position parameter to the first 5 seconds of the current time, OSLogEnumerator can still iterate over the previous 5 seconds #import "ViewController.h" #import <OSLog/OSLog.h> @interface ViewController () @property(strong, nonatomic)OSLogStore *logStore; @property(strong, nonatomic)NSDateFormatter *formatter; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; NSError *err = nil; self.logStore = [OSLogStore storeWithScope:OSLogStoreCurrentProcessIdentifier error:&err]; if (!self.logStore || err) { NSLog(@"error: %@", err); NSAssert(0, @""); } self.formatter = [[NSDateFormatter alloc] init]; [self.formatter setDateFormat:@"[yyyy-MM-dd HH:mm:ss:SSS]"]; } - (IBAction)addLog:(id)sender { static int i = 0; NSLog(@"[test] %@ this is a log with index:%d", [self.formatter stringFromDate:[NSDate date]], i++); } - (IBAction)printLogWithReverse:(id)sender { NSError *err = nil; NSPredicate *preeicate = [NSPredicate predicateWithFormat:@"composedMessage contains %@" argumentArray:@[@"[test]"]]; OSLogEnumerator *enumer = [self.logStore entriesEnumeratorWithOptions:OSLogEnumeratorReverse position:nil predicate:preeicate error:&err]; if (err) { NSLog(@"enumer error:%@", err); NSAssert(0, @""); } OSLogEntryLog *entry = nil; while (entry = [enumer nextObject]) { NSString *message = [entry composedMessage]; printf("log: %s\n", message.UTF8String); } } - (IBAction)printLogWithPosition:(id)sender { NSError *err = nil; NSPredicate *preeicate = [NSPredicate predicateWithFormat:@"composedMessage contains %@" argumentArray:@[@"[test]"]]; NSDate *posDate = [NSDate dateWithTimeIntervalSinceNow:-5]; OSLogPosition *pos = [self.logStore positionWithDate:posDate]; OSLogEnumerator *enumer = [self.logStore entriesEnumeratorWithOptions:0 position:pos predicate:preeicate error:&err]; if (err) { NSLog(@"enumer error:%@", err); NSAssert(0, @""); } const char *now = [self.formatter stringFromDate:[NSDate date]].UTF8String; const char *posStart = [self.formatter stringFromDate:posDate].UTF8String; OSLogEntryLog *entry = nil; while (entry = [enumer nextObject]) { NSString *message = [entry composedMessage]; printf("log(now:%s, pos:%s): %s\n", now, posStart, message.UTF8String); } } @end The method of - (IBAction)printLogWithReverse:(id)sender print result not reversed by time. log: [test] [2025-02-18 17:35:50:175] this is a log with index:0 log: [test] [2025-02-18 17:35:51:040] this is a log with index:1 log: [test] [2025-02-18 17:35:51:174] this is a log with index:2 log: [test] [2025-02-18 17:35:51:323] this is a log with index:3 log: [test] [2025-02-18 17:35:51:473] this is a log with index:4 log: [test] [2025-02-18 17:35:51:640] this is a log with index:5 log: [test] [2025-02-18 17:35:51:773] this is a log with index:6 log: [test] [2025-02-18 17:35:51:923] this is a log with index:7 The method of - (IBAction)printLogWithPosition:(id) print result should not contain the log from 5 seconds ago because I set the start time position in the position argument [test] [2025-02-18 17:43:58:741] this is a log with index:0 [test] [2025-02-18 17:43:58:940] this is a log with index:1 [test] [2025-02-18 17:43:59:458] this is a log with index:2 [test] [2025-02-18 17:43:59:923] this is a log with index:3 log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:58:741] this is a log with index:0 log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:58:940] this is a log with index:1 log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:59:458] this is a log with index:2 log(now:[2025-02-18 17:44:51:132], pos:[2025-02-18 17:44:46:032]): [test] [2025-02-18 17:43:59:923] this is a log with index:3

In statistical objects In MXMetricPayload histogrammedTimeToFirstDrawKey start times not equal applicationExitMetrics exit： case1: "applicationExitMetrics": { "backgroundExitData": { "cumulativeNormalAppExitCount": 3, "cumulativeMemoryPressureExitCount": 4 }, "foregroundExitData": { "cumulativeMemoryResourceLimitExitCount": 3 } }, "applicationLaunchMetrics": { "histogrammedTimeToFirstDrawKey": { "histogramNumBuckets": 14, "histogramValue": { "10": { "bucketCount": 1, "bucketStart": "1740 ms", "bucketEnd": "1749 ms" }, "2": { "bucketCount": 1, "bucketStart": "1440 ms", "bucketEnd": "1449 ms" }, "3": { "bucketCount": 2, "bucketStart": "1490 ms", "bucketEnd": "1499 ms" }, "11": { "bucketCount": 1, "bucketStart": "1780 ms", "bucketEnd": "1789 ms" }, "4": { "bucketCount": 1, "bucketStart": "1500 ms", "bucketEnd": "1509 ms" }, "5": { "bucketCount": 1, "bucketStart": "1580 ms", "bucketEnd": "1589 ms" }, "12": { "bucketCount": 1, "bucketStart": "1860 ms", "bucketEnd": "1869 ms" }, "6": { "bucketCount": 1, "bucketStart": "1620 ms", "bucketEnd": "1629 ms" }, "13": { "bucketCount": 1, "bucketStart": "1990 ms", "bucketEnd": "1999 ms" }, "7": { "bucketCount": 1, "bucketStart": "1650 ms", "bucketEnd": "1659 ms" }, "0": { "bucketCount": 1, "bucketStart": "1400 ms", "bucketEnd": "1409 ms" }, "8": { "bucketCount": 1, "bucketStart": "1660 ms", "bucketEnd": "1669 ms" }, "1": { "bucketCount": 1, "bucketStart": "1430 ms", "bucketEnd": "1439 ms" }, "9": { "bucketCount": 1, "bucketStart": "1730 ms", "bucketEnd": "1739 ms" } } }, In this Case the app cold started 15 times, but quit only 10 times， why？？ case2: "applicationExitMetrics": { "backgroundExitData": { "cumulativeMemoryPressureExitCount": 1 }, "foregroundExitData": { "cumulativeMemoryResourceLimitExitCount": 3, "cumulativeNormalAppExitCount": 1 } }, "applicationLaunchMetrics": { "histogrammedTimeToFirstDrawKey": { "histogramNumBuckets": 3, "histogramValue": { "0": { "bucketCount": 1, "bucketStart": "1490 ms", "bucketEnd": "1499 ms" }, "1": { "bucketCount": 1, "bucketStart": "1680 ms", "bucketEnd": "1689 ms" }, "2": { "bucketCount": 1, "bucketStart": "1880 ms", "bucketEnd": "1889 ms" } } }, The app cold started 3 times, but quit unexpectedly reached 5 times， why？？？