public override List <VTTQ> ReadData(Timestamp startInclusive, Timestamp endInclusive, int maxValues, BoundingMethod bounding, QualityFilter filter)
{
long N = CountData(startInclusive, endInclusive, filter);
PreparedStatement statement;
switch (bounding)
{
case BoundingMethod.TakeFirstN:
statement = stmtRawFirstN;
break;
case BoundingMethod.TakeLastN:
statement = stmtRawLastN;
break;
case BoundingMethod.CompressToN:
if (N <= maxValues)
{
return(ReadData(startInclusive, endInclusive, maxValues, BoundingMethod.TakeFirstN, filter));
}
else
{
return(ReadDataCompressed(startInclusive, endInclusive, maxValues, N, filter));
}
default:
throw new Exception($"Unknown BoundingMethod: {bounding}");
}
statement[0] = startInclusive.ToDateTime();
statement[1] = endInclusive.ToDateTime();
statement[2] = maxValues;
var filterHelper = QualityFilterHelper.Make(filter);
int initSize = N < maxValues ? (int)N : maxValues;
var res = new List <VTTQ>(initSize);
using (var reader = statement.ExecuteReader()) {
while (reader.Read())
{
VTTQ vttq = ReadVTTQ(reader);
if (filterHelper.Include(vttq.Q))
{
res.Add(vttq);
}
}
}
if (bounding == BoundingMethod.TakeLastN)
{
res.Reverse();
}
return(res);
}
private List <VTTQ> ReadDataCompressed(Timestamp startInclusive, Timestamp endInclusive, int maxValues, long count, QualityFilter filter)
{
PreparedStatement statement = stmtRawFirst;
statement[0] = startInclusive.ToDateTime();
statement[1] = endInclusive.ToDateTime();
var result = new List <VTTQ>(maxValues);
int maxIntervals = maxValues / 3;
int itemsPerInterval = (maxValues < 6) ? (int)count : (int)Math.Ceiling(((double)count) / maxIntervals);
var buffer = new List <VTTQ_D>(itemsPerInterval);
var filterHelper = QualityFilterHelper.Make(filter);
using (var reader = statement.ExecuteReader()) {
while (reader.Read())
{
VTTQ x = ReadVTTQ(reader);
if (!x.V.IsEmpty)
{
double?value = x.V.AsDouble();
if (value.HasValue && filterHelper.Include(x.Q))
{
buffer.Add(new VTTQ_D(x, value.Value));
}
}
if (buffer.Count >= itemsPerInterval)
{
FlushBuffer(result, buffer, maxValues);
}
}
}
if (buffer.Count > 0)
{
FlushBuffer(result, buffer, maxValues);
}
return(result);
}
public override List <VTTQ> ReadData(Timestamp startInclusive, Timestamp endInclusive, int maxValues, BoundingMethod bounding, QualityFilter filter)
{
long N = CountData(startInclusive, endInclusive, filter);
//double millis = (endInclusive - startInclusive).TotalMilliseconds + 1;
//double avgInterval_MS = millis / N;
//double requestInterval_MS = 60 * 1000;
//double N_2 = N;
//if (requestInterval_MS > avgInterval_MS) {
// N_2 = N / (requestInterval_MS / avgInterval_MS);
//}
PreparedStatement statement;
switch (bounding)
{
case BoundingMethod.TakeFirstN:
statement = stmtRawFirstN;
break;
case BoundingMethod.TakeLastN:
statement = stmtRawLastN;
break;
case BoundingMethod.CompressToN:
if (N <= maxValues)
{
return(ReadData(startInclusive, endInclusive, maxValues, BoundingMethod.TakeFirstN, filter));
}
else
{
return(ReadDataCompressed(startInclusive, endInclusive, maxValues, N, filter));
}
default:
throw new Exception($"Unknown BoundingMethod: {bounding}");
}
statement[0] = startInclusive.JavaTicks;
statement[1] = endInclusive.JavaTicks;
statement[2] = maxValues;
var filterHelper = QualityFilterHelper.Make(filter);
int initSize = N < maxValues ? (int)N : maxValues;
var res = new List <VTTQ>(initSize);
using (var reader = statement.ExecuteReader()) {
while (reader.Read())
{
VTTQ vttq = ReadVTTQ(reader);
if (filterHelper.Include(vttq.Q))
{
res.Add(vttq);
}
}
}
if (bounding == BoundingMethod.TakeLastN)
{
res.Reverse();
}
return(res);
}