public static string GetEstimatedAggSizeRange(EstimatedAggSize estimate)
{
if (estimate.size == 0)
{
return null;
}
else if (estimate.minSize != 0 && estimate.minSize < estimate.size && !estimate.bAggContainsAllGranularityAttributes)
{
return (estimate.minSize * 100).ToString("#0.00") + "% to " + (estimate.size * 100).ToString("#0.00") + "%";
}
else
{
return (estimate.size * 100).ToString("#0.00") + "%";
}
}
/// <summary>
/// Returns the estimated size of this aggregation. Use this signature which takes in the MeasureGroup when the agg is not attached to a ParentMeasureGroup.
/// </summary>
/// <param name="agg"></param>
/// <param name="mg1"></param>
/// <returns></returns>
public static EstimatedAggSize GetEstimatedSize(Aggregation agg, MeasureGroup mg1)
{
double size = 0;
double minSize = 0;
bool bAggContainsAllGranularityAttributes = true;
AggregationAttribute aggAttr;
AggregationDimension aggDim;
double dblAggCardinality = 1;
long iNumSurrogateKeysInAgg = 0;
int iMeasureGroupDimensionsCount = 0;
long lngMaxAggDimensionCardinality = 0;
foreach (MeasureGroupDimension mgDim in mg1.Dimensions)
{
long iDimGranularityCardinality = 0;
double dblDimAggCardinality = 1;
bool bDimAggCardinalityFound = false;
if (!(mgDim is RegularMeasureGroupDimension)) continue; //m2m dimensions apparently aren't stored in the agg since they're calculated at runtime
iMeasureGroupDimensionsCount++; //don't count m2m dimensions
MeasureGroupAttribute granularity = null;
RegularMeasureGroupDimension regMgDim = (RegularMeasureGroupDimension)mgDim;
foreach (MeasureGroupAttribute mgDimAttr in regMgDim.Attributes)
{
if (mgDimAttr.Type == MeasureGroupAttributeType.Granularity)
{
iDimGranularityCardinality = mgDimAttr.Attribute.EstimatedCount;
granularity = mgDimAttr;
break;
}
}
aggDim = agg.Dimensions.Find(mgDim.CubeDimensionID);
if (aggDim == null || granularity == null || aggDim.Attributes.Find(granularity.AttributeID) == null)
bAggContainsAllGranularityAttributes = false;
if (aggDim != null)
{
foreach (CubeAttribute cubeAttr in mgDim.CubeDimension.Attributes)
{
aggAttr = aggDim.Attributes.Find(cubeAttr.AttributeID);
if (aggAttr != null)
{
if (!CanReachAttributeFromChildInAgg(aggAttr, mgDim.Dimension.KeyAttribute, false)) //redundant attributes don't increase the cardinality of the attribute
{
dblDimAggCardinality *= (cubeAttr.Attribute.EstimatedCount == 0 ? 1 : cubeAttr.Attribute.EstimatedCount);
}
bDimAggCardinalityFound = true;
iNumSurrogateKeysInAgg++; //apparently every key, even redundant keys, get stored in the agg
}
}
}
if (dblDimAggCardinality > iDimGranularityCardinality)
{
//shouldn't be more than granularity cardinality because auto-exists prevents that
dblDimAggCardinality = (iDimGranularityCardinality == 0 ? 1 : iDimGranularityCardinality);
}
if (bDimAggCardinalityFound)
{
dblAggCardinality *= dblDimAggCardinality;
if (lngMaxAggDimensionCardinality < dblAggCardinality) lngMaxAggDimensionCardinality = (long)dblDimAggCardinality;
}
}
if (mg1.EstimatedRows != 0 && dblAggCardinality != 0)
{
long iMeasureBytes = 0;
foreach (Microsoft.AnalysisServices.Measure m in mg1.Measures)
{
if (m.DataType == MeasureDataType.Inherited)
{
if (m.Source.DataSize > 0)
iMeasureBytes += m.Source.DataSize;
else if (m.Source.DataType == System.Data.OleDb.OleDbType.Integer)
iMeasureBytes += 4;
else if (m.Source.DataType == System.Data.OleDb.OleDbType.SmallInt)
iMeasureBytes += 2;
else if (m.Source.DataType == System.Data.OleDb.OleDbType.TinyInt)
iMeasureBytes += 1;
else
iMeasureBytes += 8;
}
else
{
if (m.DataType == MeasureDataType.Integer)
iMeasureBytes += 4;
else if (m.DataType == MeasureDataType.SmallInt)
iMeasureBytes += 2;
else if (m.DataType == MeasureDataType.TinyInt)
iMeasureBytes += 1;
else
iMeasureBytes += 8;
}
}
//the size of each row is 4 bytes for each surrogate key plus the size of measures
long lngFactTableRowSize = (iMeasureGroupDimensionsCount * 4 + iMeasureBytes);
long lngAggRowSize = (iNumSurrogateKeysInAgg * 4 + iMeasureBytes);
if (dblAggCardinality > mg1.EstimatedRows) //this is not possible in the data
{
dblAggCardinality = mg1.EstimatedRows;
}
//multiply the estimated rows by the size of each row
size = ((double)(dblAggCardinality * lngAggRowSize)) / ((double)(mg1.EstimatedRows * lngFactTableRowSize));
//purposefully don't prevent size from being over 1 because an agg can be larger than the fact table if it has more dimension attribute keys than the fact table
if (lngMaxAggDimensionCardinality > mg1.EstimatedRows) //this is not possible in the data
{
lngMaxAggDimensionCardinality = mg1.EstimatedRows;
}
//calculate the min size (best case scenario when there is lots of sparsity in fact table) so you can present a range to the user and give the user an idea of the uncertainty
minSize = ((double)(lngMaxAggDimensionCardinality * lngAggRowSize)) / ((double)(mg1.EstimatedRows * lngFactTableRowSize));
}
EstimatedAggSize ret = new EstimatedAggSize();
ret.minSize = minSize;
ret.size = size;
ret.bAggContainsAllGranularityAttributes = bAggContainsAllGranularityAttributes;
ret.agg = agg;
return ret;
}
