public SnapDBClient(string hostAddress, int port, string instanceName, ulong startTime, ulong endTime, int frameRate, IEnumerable<ulong> pointIDs)
{
m_client = new HistorianClient(hostAddress, port);
m_database = m_client.GetDatabase<HistorianKey, HistorianValue>(instanceName);
m_key = new HistorianKey();
m_value = new HistorianValue();
SeekFilterBase<HistorianKey> timeFilter = TimestampSeekFilter.CreateFromRange<HistorianKey>(DataPoint.RoundTimestamp(startTime, frameRate), DataPoint.RoundTimestamp(endTime, frameRate));
MatchFilterBase<HistorianKey, HistorianValue> pointFilter = PointIdMatchFilter.CreateFromList<HistorianKey, HistorianValue>(pointIDs);
m_stream = m_database.Read(SortedTreeEngineReaderOptions.Default, timeFilter, pointFilter);
}
/// <summary>
/// Read historian data from server.
/// </summary>
/// <param name="database">Client database to use for query.</param>
/// <param name="startTime">Start time of query.</param>
/// <param name="stopTime">Stop time of query.</param>
/// <param name="measurementIDs">Measurement IDs to query - or <c>null</c> for all available points.</param>
/// <param name="resolution">Resolution for data query.</param>
/// <param name="seriesLimit">Maximum number of points per series.</param>
/// <param name="forceLimit">Flag that determines if series limit should be strictly enforced.</param>
/// <param name="cancellationToken">Cancellation token for query.</param>
/// <returns>Enumeration of <see cref="TrendValue"/> instances read for time range.</returns>
public static IEnumerable<TrendValue> GetHistorianData(ClientDatabaseBase<HistorianKey, HistorianValue> database, DateTime startTime, DateTime stopTime, ulong[] measurementIDs, Resolution resolution, int seriesLimit, bool forceLimit, ICancellationToken cancellationToken = null)
{
if ((object)cancellationToken == null)
cancellationToken = new CancellationToken();
if ((object)database == null)
yield break;
TimeSpan resolutionInterval = resolution.GetInterval();
SeekFilterBase<HistorianKey> timeFilter;
MatchFilterBase<HistorianKey, HistorianValue> pointFilter = null;
HistorianKey key = new HistorianKey();
HistorianValue value = new HistorianValue();
// Set data scan resolution
if (resolution == Resolution.Full)
{
timeFilter = TimestampSeekFilter.CreateFromRange<HistorianKey>(startTime, stopTime);
}
else
{
BaselineTimeInterval interval = BaselineTimeInterval.Second;
if (resolutionInterval.Ticks < Ticks.PerMinute)
interval = BaselineTimeInterval.Second;
else if (resolutionInterval.Ticks < Ticks.PerHour)
interval = BaselineTimeInterval.Minute;
else if (resolutionInterval.Ticks == Ticks.PerHour)
interval = BaselineTimeInterval.Hour;
startTime = startTime.BaselinedTimestamp(interval);
stopTime = stopTime.BaselinedTimestamp(interval);
timeFilter = TimestampSeekFilter.CreateFromIntervalData<HistorianKey>(startTime, stopTime, resolutionInterval, new TimeSpan(TimeSpan.TicksPerMillisecond));
}
Dictionary<ulong, DataRow> metadata = null;
LocalOutputAdapter historianAdapter;
if (LocalOutputAdapter.Instances.TryGetValue(database.Info?.DatabaseName ?? DefaultInstanceName, out historianAdapter))
metadata = historianAdapter?.Measurements;
if ((object)metadata == null)
yield break;
// Setup point ID selections
if ((object)measurementIDs != null)
pointFilter = PointIdMatchFilter.CreateFromList<HistorianKey, HistorianValue>(measurementIDs);
else
measurementIDs = metadata.Keys.ToArray();
// Start stream reader for the provided time window and selected points
Dictionary<ulong, long> pointCounts = new Dictionary<ulong, long>(measurementIDs.Length);
Dictionary<ulong, long> intervals = new Dictionary<ulong, long>(measurementIDs.Length);
Dictionary<ulong, ulong> lastTimes = new Dictionary<ulong, ulong>(measurementIDs.Length);
double range = (stopTime - startTime).TotalSeconds;
ulong pointID, timestamp, resolutionSpan = (ulong)resolutionInterval.Ticks, baseTicks = (ulong)UnixTimeTag.BaseTicks.Value;
long pointCount;
DataRow row;
if (resolutionSpan <= 1UL)
resolutionSpan = Ticks.PerSecond;
if (seriesLimit < 1)
seriesLimit = 1;
// Estimate total measurement counts per point so decimation intervals for each series can be calculated
foreach (ulong measurementID in measurementIDs)
{
if (resolution == Resolution.Full)
pointCounts[measurementID] = metadata.TryGetValue(measurementID, out row) ? (long)(int.Parse(row["FramesPerSecond"].ToString()) * range) : 2;
else
pointCounts[measurementID] = (long)(range / resolutionInterval.TotalSeconds.NotZero(1.0D));
}
foreach (ulong measurementID in pointCounts.Keys)
intervals[measurementID] = (pointCounts[measurementID] / seriesLimit).NotZero(1L);
lock (database)
{
TreeStream<HistorianKey, HistorianValue> stream = database.Read(SortedTreeEngineReaderOptions.Default, timeFilter, pointFilter);
while (stream.Read(key, value) && !cancellationToken.IsCancelled)
{
pointID = key.PointID;
timestamp = key.Timestamp;
pointCount = pointCounts[pointID];
if (pointCount++ % intervals[pointID] == 0 || (!forceLimit && timestamp - lastTimes.GetOrAdd(pointID, 0UL) > resolutionSpan))
yield return new TrendValue
{
ID = (long)pointID,
Timestamp = (timestamp - baseTicks) / (double)Ticks.PerMillisecond,
Value = value.AsSingle
};
pointCounts[pointID] = pointCount;
lastTimes[pointID] = timestamp;
}
}
}