GetNextIncludedTimeUtc method is very slow or crashes

[al007]

The GetNextIncludedTimeUtc method of ICalendar can be extremely slow in certain conditions. The below example creates a calendar that excludes public holidays, weekends, and nighttime. A call to the GetNextIncludedTimeUtc method of such a calendar takes more than 13 seconds on my machine.

Tested version Quartz 3.8.0 from Nuget as well as the latest version of the main branch of this repo.

[Test]
public void GetNextIncludedTimeUtc()
{
    TimeZoneInfo timeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

    var holidayCalendar = new HolidayCalendar()
    {
        TimeZone = timeZone,
    };
    holidayCalendar.AddExcludedDate(new DateTime(2024, 2, 19));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 5, 27));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 6, 19));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 7, 4));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 9, 2));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 10, 14));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 11));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 28));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 12, 25));

    var weeklyCalendar = new WeeklyCalendar(holidayCalendar)
    {
        TimeZone = timeZone,
    };
    var calendar = new DailyCalendar(weeklyCalendar, "06:00", "22:00")
    {
        TimeZone = timeZone,
        InvertTimeRange = true,
    };
    var time = new DateTime(2024, 2, 5, 10, 6, 0, DateTimeKind.Utc);
    var expected = new DateTime(2024, 2, 5, 14, 0, 0, DateTimeKind.Utc);

    var d = calendar.GetNextIncludedTimeUtc(time); // takes 13 seconds to execute!
    d.Should().Be(expected);
}

[al007]

The following calendar configuration crashes on GetNextIncludedTimeUtc: System.ArgumentOutOfRangeException : The UTC time represented when the offset is applied must be between year 0 and 10,000. (Parameter 'offset')

    [Test]
    public void GetNextIncludedTimeUtc()
    {
        TimeZoneInfo timeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

        var weeklyCalendar = new WeeklyCalendar()
        {
            TimeZone = timeZone,
        };

        var dailyCalendar = new DailyCalendar(weeklyCalendar, "06:00", "22:00")
        {
            TimeZone = timeZone,
            InvertTimeRange = true,
        };

        var holidayCalendar = new HolidayCalendar(dailyCalendar)
        {
            TimeZone = timeZone,
        };
        holidayCalendar.AddExcludedDate(new DateTime(2024, 2, 19));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 5, 27));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 6, 19));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 7, 4));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 9, 2));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 10, 14));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 11));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 28));
        holidayCalendar.AddExcludedDate(new DateTime(2024, 12, 25));

        var time = new DateTime(2024, 2, 5, 10, 6, 0, DateTimeKind.Utc);
        var expected = new DateTime(2024, 2, 5, 14, 0, 0, DateTimeKind.Utc);

        var d = holidayCalendar.GetNextIncludedTimeUtc(time); // throws System.ArgumentOutOfRangeException : The UTC time represented when the offset is applied must be between year 0 and 10,000. (Parameter 'offset')
        d.Should().Be(expected);
    }

[jafin]

Possibly related dotnet/runtime#25075
One hotspot is the calls to TimeZoneInfo.ConvertTime in a tight loop.

[lahma]

The problem here is that DailyCalendar.GetNextIncludedTimeUtc() iterates checking every next millisecond whether it would fit the range. Increments could be larger / start position could be calculated more precisely when we know that there's no need for millisecond or even second precision.

[jafin]

@al007 Please check if latest 3.x / master branches in repo resolves your issue.

[al007]

No, unfortunately, it does not. The example from the 1st post in this thread works even slower now: 20 seconds for .net8 and 50 seconds for net472. However, it does fix the crash for the 2nd example.

[jafin]

The example you provided should be in the repo, it executes here in about 43ms.
This is from 3.x branch.

Can you please try running.?

dotnet test --filter GetNextIncludedTimeUtc_CrashOriginal2270

Passed!  - Failed:     0, Passed:     1, Skipped:     0, Total:     1, Duration: 43 ms - Quartz.Tests.Unit.dll (net8.0)

[al007]

@jafin , this method has two issues: poor performance and a crash. I reported them together because I thought they were related and re-working the algorithm would fix both.

Performance issue happens for the following calendar configuration HolidayCalendar->WeeklyCalendar->DailyCalendar, see 1st post here. It is not fixed in the 3.x branch. It takes from 20 to 50 seconds as described above.

The crash happens for calendar WeeklyCalendar->DailyCalendar->HolidayCalendar, see 2nd post here. It is fixed in the 3.x branch and runs fast.

[jafin]

@al007 Perhaps I am missing something I copied the example, ran the below against 3.x branch, completed in ~20ms

Passed!  - Failed:     0, Passed:     1, Skipped:     0, Total:     1, Duration: 11 ms - Quartz.Tests.Unit.dll (net8.0)
Passed!  - Failed:     0, Passed:     1, Skipped:     0, Total:     1, Duration: 22 ms - Quartz.Tests.Unit.dll (net472)

[Test]
public void GetNextIncludedTimeUtcFirstIssue()
{
    TimeZoneInfo timeZone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");

    var holidayCalendar = new HolidayCalendar()
    {
        TimeZone = timeZone,
    };
    holidayCalendar.AddExcludedDate(new DateTime(2024, 2, 19));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 5, 27));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 6, 19));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 7, 4));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 9, 2));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 10, 14));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 11));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 11, 28));
    holidayCalendar.AddExcludedDate(new DateTime(2024, 12, 25));

    var weeklyCalendar = new WeeklyCalendar(holidayCalendar)
    {
        TimeZone = timeZone,
    };
    var calendar = new DailyCalendar(weeklyCalendar, "06:00", "22:00")
    {
        TimeZone = timeZone,
        InvertTimeRange = true,
    };
    var time = new DateTime(2024, 2, 5, 10, 6, 0, DateTimeKind.Utc);
    var expected = new DateTime(2024, 2, 5, 14, 0, 0, DateTimeKind.Utc);

    var d = calendar.GetNextIncludedTimeUtc(time); // takes 13 seconds to execute!
    d.Should().Be(expected);
}