private async Task FetchMeasurementsAsync(DateTime Hour)
{
// Discard all old data.
hourData = new Dictionary <DateTime, List <Measurement> >();
// Determine where to stop.
var endHour = Hour.AddHours(PrefetchSize);
if (endHour > CacheEnd)
{
endHour = CacheEnd;
}
// Initialize the hour data cache.
for (DateTime i = Hour; i < endHour; i = i.AddHours(1))
{
hourData[i] = new List <Measurement>();
}
// Fetch raw data.
var measurements = await Database.GetRawMeasurementsAsync(SensorId, Hour, endHour);
// Insert data into cache.
foreach (var item in measurements)
{
var hour = MeasurementAggregation.Quantize(item.Time, TimeSpan.FromHours(1));
hourData[hour].Add(item);
}
}
/// <summary>
/// Computes the given number of
/// </summary>
private void ComputeInCacheHourAverages(
DateTime Start, int Offset, int Count, Measurement[] Target)
{
for (int i = 0; i < Count; i++)
{
var hour = Start.AddHours(i + Offset);
Target[i + Offset] = MeasurementAggregation.Aggregate(hourData[hour], SensorId, hour);
}
}
/// <summary>
/// Gets the hour average for the given hour.
/// </summary>
private async Task <Measurement> GetRealHourAverageAsync(DateTime Hour)
{
if (hourAverages == null)
{
await FetchHourAveragesAsync();
}
Measurement result;
if (hourAverages.TryGetValue(Hour, out result))
{
return(result);
}
else
{
result = MeasurementAggregation.Aggregate(
await GetMeasurementsAsync(Hour), SensorId, Hour);
hourAverages[Hour] = result;
return(result);
}
}
/// <summary>
/// Gets the day average for the given day.
/// </summary>
private async Task <Measurement> GetRealDayAverageAsync(DateTime Day)
{
if (dayAverages == null)
{
await FetchDayAveragesAsync();
}
Measurement result;
if (dayAverages.TryGetValue(Day, out result))
{
return(result);
}
else
{
result = MeasurementAggregation.Aggregate(
await GetRealHourAveragesAsync(Day, 24),
SensorId, Day, Enumerable.Average);
dayAverages[Day] = result;
return(result);
}
}
/// <summary>
/// Gets the month-average for the given month.
/// </summary>
public async Task <Measurement> GetMonthAverageAsync(DateTime Month)
{
if (monthAverages == null)
{
await FetchMonthAveragesAsync();
}
Measurement result;
if (monthAverages.TryGetValue(Month, out result))
{
return(result);
}
else
{
var timeSpan = Month.AddMonths(1) - Month;
result = MeasurementAggregation.Aggregate(
await GetRealDayAveragesAsync(Month, (int)timeSpan.TotalDays),
SensorId, Month, Enumerable.Average);
monthAverages[Month] = result;
return(result);
}
}
private async Task <IEnumerable <Measurement> > GetMeasurementsAsync(FrozenPeriod Period)
{
const int MinutesPerHour = 60;
switch (Period.Compaction)
{
case CompactionLevel.DayAverages:
case CompactionLevel.HourAverages:
case CompactionLevel.Measurements:
// We'll re-create measurement data by replicating
// hour-average data.
var results = await GetHourAveragesAsync(
MeasurementAggregation.Quantize(Period.StartTime, TimeSpan.FromHours(1)),
(int)Math.Ceiling(Period.Duration.TotalHours));
return(ReplicateEach(results, Period.StartTime, Period.EndTime, TimeSpan.FromMinutes(1), MinutesPerHour).ToArray());
case CompactionLevel.None:
default:
// We can just fetch real measurements from the database.
return(await Database.GetRawMeasurementsAsync(SensorId, Period.StartTime, Period.EndTime));
}
}
private async Task <IEnumerable <Measurement> > GetHourAveragesAsync(FrozenPeriod Period)
{
const int HoursPerDay = 24;
switch (Period.Compaction)
{
case CompactionLevel.DayAverages:
case CompactionLevel.HourAverages:
// We'll re-create hour-average data by replicating
// day-average data.
var results = await GetDayAveragesAsync(
MeasurementAggregation.Quantize(Period.StartTime, TimeSpan.FromDays(1)),
(int)Math.Ceiling(Period.Duration.TotalDays));
return(ReplicateEach(results, Period.StartTime, Period.EndTime, TimeSpan.FromHours(1), HoursPerDay).ToArray());
case CompactionLevel.Measurements:
case CompactionLevel.None:
default:
// We can just fetch or create "real" hour-average data.
return(await GetRealHourAveragesAsync(Period.StartTime, (int)Period.Duration.TotalHours));
}
}
private async Task <IEnumerable <Measurement> > GetDayAveragesAsync(FrozenPeriod Period)
{
switch (Period.Compaction)
{
case CompactionLevel.DayAverages:
// We'll re-create day-average data by replicating
// month-average data.
var results = new List <Measurement>();
for (var day = Period.StartTime; day < Period.EndTime; day = day.AddDays(1))
{
var monthMeasurement = await GetMonthAverageAsync(MeasurementAggregation.QuantizeMonth(day));
results.Add(new Measurement(SensorId, day, monthMeasurement.MeasuredData, monthMeasurement.Notes));
}
return(results);
case CompactionLevel.HourAverages:
case CompactionLevel.Measurements:
case CompactionLevel.None:
default:
// We can just fetch or create "real" day-average data.
return(await GetRealDayAveragesAsync(Period.StartTime, (int)Period.Duration.TotalDays));
}
}
