public ColumnStatistics GetLeafToLeafStatistics(MatchEdge nodeEdge, MatchEdge componentEdge)
{
var edgeTuple = new Tuple <string, string>(nodeEdge.EdgeAlias, componentEdge.EdgeAlias);
if (LeafToLeafSelectivity.ContainsKey(edgeTuple))
{
return(LeafToLeafSelectivity[edgeTuple]);
}
var mergedStatistics = ColumnStatistics.UpdateHistogram(Context.GetEdgeStatistics(nodeEdge), Context.GetEdgeStatistics(componentEdge));
LeafToLeafSelectivity[edgeTuple] = mergedStatistics;
return(mergedStatistics);
}
public MatchComponent(MatchNode node) : this()
{
Nodes.Add(node);
MaterializedNodeSplitCount[node] = 0;
StatisticsDict[node] = new ColumnStatistics {
Selectivity = 1.0 / node.TableRowCount
};
Size *= node.EstimatedRows;
EstimateSize *= node.EstimatedRows;
TableRef = new WNamedTableReference
{
Alias = new Identifier {
Value = node.RefAlias
},
TableObjectName = node.TableObjectName
};
}
/// <summary>
/// Transit from current component to the new component in the next state given the Node Unit
/// </summary>
/// <param name="candidateTree"></param>
/// <param name="densityDict"></param>
/// <param name="subGraph"></param>
/// <param name="statisticsCalculator"></param>
/// <returns></returns>
public MatchComponent GetNextState(
OneHeightTree candidateTree,
Dictionary <string, double> densityDict,
IMatchJoinStatisticsCalculator statisticsCalculator)
{
var newComponent = new MatchComponent(this);
var root = candidateTree.TreeRoot;
WBooleanExpression joinCondition = null;
string nodeName = "";
// Update Nodes
if (newComponent.MaterializedNodeSplitCount.ContainsKey(root))
{
newComponent.MaterializedNodeSplitCount[root]++;
nodeName = newComponent.GetNodeRefName(root);
joinCondition = new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = root.RefAlias
},
new Identifier {
Value = "GlobalNodeId"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = nodeName
},
new Identifier {
Value = "GlobalNodeId"
}
),
},
ComparisonType = BooleanComparisonType.Equals
};
}
else
{
nodeName = root.RefAlias;
newComponent.Nodes.Add(root);
newComponent.MaterializedNodeSplitCount[root] = 0;
newComponent.StatisticsDict[root] = new ColumnStatistics {
Selectivity = 1.0 / root.TableRowCount
};
}
// Constructs table reference
WTableReference nodeTable = new WNamedTableReference
{
Alias = new Identifier {
Value = nodeName
},
TableObjectName = root.TableObjectName
};
WTableReference compTable = newComponent.TableRef;
// Updates join conditions
double selectivity = 1.0;
double degrees = 1.0;
var DensityCount = new Dictionary <string, int>(StringComparer.CurrentCultureIgnoreCase);
List <MatchEdge> inEdges;
if (newComponent.UnmaterializedNodeMapping.TryGetValue(root, out inEdges))
{
var firstEdge = inEdges.First();
bool materialized = newComponent.EdgeMaterilizedDict[firstEdge];
newComponent.UnmaterializedNodeMapping.Remove(root);
selectivity *= 1.0 / root.TableRowCount;
// Component materialized edge to root
if (materialized)
{
joinCondition = WBooleanBinaryExpression.Conjunction(joinCondition, new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = firstEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = nodeName
},
new Identifier {
Value = "GlobalNodeId"
}
)
},
ComparisonType = BooleanComparisonType.Equals
});
//var statistics = ColumnStatistics.UpdateHistogram(newComponent.StatisticsDict[root],
// new ColumnStatistics {Selectivity = 1.0/root.TableRowCount});
//selectivity *= statistics.Selectivity;
//newComponent.StatisticsDict[root] = statistics;
if (DensityCount.ContainsKey(root.TableObjectName.ToString()))
{
DensityCount[root.TableObjectName.ToString()]++;
}
else
{
DensityCount[root.TableObjectName.ToString()] = 1;
}
}
// Component unmaterialized edge to root
else
{
ColumnStatistics statistics = null;
foreach (var edge in inEdges)
{
// Update component table
compTable = SpanTableRef(compTable, edge, newComponent.GetNodeRefName(edge.SourceNode));
newComponent.EdgeMaterilizedDict[edge] = true;
joinCondition = WBooleanBinaryExpression.Conjunction(joinCondition,
new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = edge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = nodeName
},
new Identifier {
Value = "GlobalNodeId"
}
)
},
ComparisonType = BooleanComparisonType.Equals
});
statistics = ColumnStatistics.UpdateHistogram(statistics,
newComponent.Context.GetEdgeStatistics(edge));
selectivity *= statistics.Selectivity;
}
newComponent.StatisticsDict[root] = statistics;
if (DensityCount.ContainsKey(root.TableObjectName.ToString()))
{
DensityCount[root.TableObjectName.ToString()] += inEdges.Count;
}
else
{
DensityCount[root.TableObjectName.ToString()] = inEdges.Count;
}
}
}
var jointEdges = candidateTree.MaterializedEdges;
int sinkToSinkCount = 0;
foreach (var jointEdge in jointEdges)
{
// Update node table
nodeTable = SpanTableRef(nodeTable, jointEdge, nodeName);
degrees *= jointEdge.AverageDegree;
newComponent.EdgeMaterilizedDict[jointEdge] = true;
var sinkNode = jointEdge.SinkNode;
// Leaf to component materialized node
if (newComponent.MaterializedNodeSplitCount.ContainsKey(sinkNode))
{
joinCondition = WBooleanBinaryExpression.Conjunction(joinCondition,
new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = jointEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = sinkNode.RefAlias
},
new Identifier {
Value = "GlobalNodeId"
}
)
},
ComparisonType = BooleanComparisonType.Equals
});
var statistics = ColumnStatistics.UpdateHistogram(newComponent.StatisticsDict[sinkNode],
newComponent.Context.GetEdgeStatistics(jointEdge));
selectivity *= statistics.Selectivity;
newComponent.StatisticsDict[sinkNode] = statistics;
if (DensityCount.ContainsKey(sinkNode.TableObjectName.ToString()))
{
DensityCount[sinkNode.TableObjectName.ToString()]++;
}
else
{
DensityCount[sinkNode.TableObjectName.ToString()] = 1;
}
}
// Leaf to component unmaterialized node
else
{
inEdges = newComponent.UnmaterializedNodeMapping[sinkNode];
var firstEdge = inEdges.First();
bool materlizedEdge = newComponent.EdgeMaterilizedDict[firstEdge];
// Leaf to materialized leaf
if (materlizedEdge)
{
joinCondition = WBooleanBinaryExpression.Conjunction(joinCondition,
new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = jointEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = firstEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
)
},
ComparisonType = BooleanComparisonType.Equals
});
sinkToSinkCount++;
var statistics = ColumnStatistics.UpdateHistogram(newComponent.StatisticsDict[sinkNode],
newComponent.Context.GetEdgeStatistics(jointEdge));
selectivity *= statistics.Selectivity;
newComponent.StatisticsDict[sinkNode] = statistics;
}
// Leaf to unmaterialized leaf
else
{
ColumnStatistics compSinkNodeStatistics = null;
foreach (var inEdge in inEdges)
{
compTable = SpanTableRef(compTable, inEdge, newComponent.GetNodeRefName(inEdge.SourceNode));
newComponent.EdgeMaterilizedDict[inEdge] = true;
joinCondition = WBooleanBinaryExpression.Conjunction(joinCondition,
new WBooleanComparisonExpression
{
FirstExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = jointEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
),
},
SecondExpr = new WColumnReferenceExpression
{
ColumnType = ColumnType.Regular,
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier {
Value = inEdge.EdgeAlias
},
new Identifier {
Value = "Sink"
}
)
},
ComparisonType = BooleanComparisonType.Equals
});
sinkToSinkCount++;
var leafToLeafStatistics = statisticsCalculator.GetLeafToLeafStatistics(jointEdge, inEdge);
selectivity *= leafToLeafStatistics.Selectivity;
compSinkNodeStatistics =
ColumnStatistics.UpdateHistogram(compSinkNodeStatistics,
newComponent.Context.GetEdgeStatistics(inEdge));
}
newComponent.StatisticsDict[sinkNode] = compSinkNodeStatistics;
}
}
}
var unmatEdges = candidateTree.UnmaterializedEdges;
foreach (var unmatEdge in unmatEdges)
{
newComponent.EdgeMaterilizedDict[unmatEdge] = false;
newComponent.Nodes.Add(unmatEdge.SinkNode);
var sinkNodeInEdges = newComponent.UnmaterializedNodeMapping.GetOrCreate(unmatEdge.SinkNode);
sinkNodeInEdges.Add(unmatEdge);
degrees *= unmatEdge.AverageDegree;
}
// Calculate Estimated Join Selectivity & Estimated Node Size
double estimatedSelectity = 1.0;
int count = 0;
bool sinkJoin = false;
foreach (var item in densityDict.Where(e => DensityCount.ContainsKey(e.Key)))
{
var density = item.Value;
var curJoinCount = DensityCount[item.Key];
var curJoinSelectitivy = Math.Pow(density, 2 - Math.Pow(2, 1 - curJoinCount));
if (!sinkJoin && ColumnStatistics.DefaultDensity < density)
{
var curSinkJoinSelectivity = Math.Pow(ColumnStatistics.DefaultDensity,
2 - Math.Pow(2, 1 - sinkToSinkCount));
estimatedSelectity *= Math.Pow(curSinkJoinSelectivity, Math.Pow(2, -count));
count += sinkToSinkCount;
sinkJoin = true;
}
estimatedSelectity *= Math.Pow(curJoinSelectitivy, Math.Pow(2, -count));
count += curJoinCount;
}
var estimatedNodeUnitSize = root.EstimatedRows *
Math.Pow(1000, candidateTree.MaterializedEdges.Count + candidateTree.UnmaterializedEdges.Count);
// Update Table Reference
newComponent.TableRef = GetPlanAndUpdateCost(candidateTree, newComponent, nodeTable, compTable, joinCondition,
degrees, selectivity, estimatedNodeUnitSize, estimatedSelectity);
return(newComponent);
}
/// <summary>
/// Merger Two Histograms
/// </summary>
/// <param name="curStatistics"></param>
/// <param name="newStatistics"></param>
/// <param name="currentJoin"></param>
/// <returns></returns>
internal static ColumnStatistics UpdateHistogram(ColumnStatistics curStatistics, ColumnStatistics newStatistics)
{
if (curStatistics == null)
{
return(newStatistics);
}
else if (newStatistics == null)
{
return(curStatistics);
}
var resHistogram = new Dictionary <long, Tuple <double, bool> >();
var curHistogram = curStatistics.Histogram;
var newHistogram = newStatistics.Histogram;
if (!curHistogram.Any())
{
return(new ColumnStatistics
{
Density = newStatistics.Density,
Histogram = newHistogram,
Selectivity = curStatistics.Selectivity * newStatistics.Selectivity,
});
}
if (!newHistogram.Any())
{
return(new ColumnStatistics
{
Density = curStatistics.Density,
Histogram = curHistogram,
Selectivity = curStatistics.Selectivity * newStatistics.Selectivity,
});
}
var curNotPopularCount = 0.0;
var newNotPopularCount = 0.0;
var curDefaultRow = curStatistics.Density * curStatistics.RowCount;
var newDefaultRow = newStatistics.Density * newStatistics.RowCount;
IEnumerator <KeyValuePair <long, Tuple <double, bool> > > newEntry = null;
bool fisrstMatch = false;
bool newHistogramEnd = false;
double resRowCount = 0.0;
List <long> notPopularValues = new List <long>();
foreach (var entry in curHistogram)
{
if (!fisrstMatch)
{
if (newHistogram.ContainsKey(entry.Key))
{
fisrstMatch = true;
var entry1 = entry;
newEntry = newHistogram.SkipWhile(e => e.Key != entry1.Key).GetEnumerator();
newEntry.MoveNext();
if (!entry.Value.Item2)
{
curNotPopularCount -= entry.Value.Item1;
}
if (!newEntry.Current.Value.Item2)
{
newNotPopularCount -= newEntry.Current.Value.Item1;
}
}
}
if (fisrstMatch)
{
if (newHistogramEnd || entry.Key < newEntry.Current.Key)
{
var curTuple = entry.Value;
if (curTuple.Item2 == true)
{
var tmpCount = curTuple.Item1 * newDefaultRow;
resRowCount += tmpCount;
resHistogram.Add(entry.Key, new Tuple <double, bool>(tmpCount, true));
}
else
{
notPopularValues.Add(entry.Key);
curNotPopularCount += curTuple.Item1;
resHistogram.Add(entry.Key, null);
}
}
else if (entry.Key > newEntry.Current.Key)
{
while (entry.Key > newEntry.Current.Key)
{
var newTuple = newEntry.Current.Value;
if (newTuple.Item2 == true)
{
var tmpCount = newTuple.Item1 * curDefaultRow;
resRowCount += tmpCount;
resHistogram.Add(newEntry.Current.Key, new Tuple <double, bool>(tmpCount, true));
}
else
{
notPopularValues.Add(newEntry.Current.Key);
newNotPopularCount += newTuple.Item1;
resHistogram.Add(newEntry.Current.Key, null);
}
if (!newEntry.MoveNext())
{
newHistogramEnd = true;
break;
}
}
if (newHistogramEnd)
{
break;
}
}
else
{
var curTuple = entry.Value;
var newTuple = newEntry.Current.Value;
if (curTuple.Item2 == false && newTuple.Item2 == false)
{
notPopularValues.Add(entry.Key);
curNotPopularCount += curTuple.Item1;
newNotPopularCount += newTuple.Item1;
resHistogram.Add(entry.Key, null);
}
else
{
var count1 = curTuple.Item2 ? curTuple.Item1 : curDefaultRow;
var count2 = newTuple.Item2 ? newTuple.Item1 : newDefaultRow;
var tmpCount = count1 * count2;
resRowCount += tmpCount;
resHistogram.Add(entry.Key, new Tuple <double, bool>(tmpCount, true));
}
if (!newEntry.MoveNext())
{
newHistogramEnd = true;
}
}
}
}
double density = -1;
if (notPopularValues.Any())
{
var resDefaultRow = curNotPopularCount * newNotPopularCount *
Math.Min(curDefaultRow / curNotPopularCount, newDefaultRow / newNotPopularCount);
resRowCount += resDefaultRow;
resDefaultRow = resDefaultRow / notPopularValues.Count;
density = resDefaultRow / resRowCount;
foreach (var value in notPopularValues)
{
resHistogram[value] = new Tuple <double, bool>(resDefaultRow, false);
}
}
return(new ColumnStatistics
{
Histogram = resHistogram,
Density = density < 0 ? Math.Max(curStatistics.Density, newStatistics.Density) : density,
MaxValue = Math.Max(curStatistics.MaxValue, newStatistics.MaxValue),
RowCount = resRowCount,
Selectivity = resRowCount / (curStatistics.RowCount * newStatistics.RowCount),
});
}
public MatchComponent(MatchNode node):this()
{
Nodes.Add(node);
MaterializedNodeSplitCount[node] = 0;
StatisticsDict[node] = new ColumnStatistics{Selectivity = 1.0/node.TableRowCount};
Size *= node.EstimatedRows;
EstimateSize *= node.EstimatedRows;
TableRef = new WNamedTableReference
{
Alias = new Identifier { Value = node.RefAlias},
TableObjectName = node.TableObjectName
};
}
/// <summary>
/// Update the statistics histogram for the edge given the sink id list.
/// Bucket size is pre-defined
/// </summary>
/// <param name="edge"></param>
/// <param name="sinkList"></param>
private void UpdateEdgeHistogram(MatchEdge edge, List<long> sinkList)
{
sinkList.Sort();
var rowCount = sinkList.Count;
var statistics = new ColumnStatistics
{
RowCount = rowCount
};
var height = (int)(rowCount / BucketNum);
var popBucketCount = 0;
var popValueCount = 0;
var bucketCount = 0;
// If number in each bucket is very small, then generate a Frequency Histogram
if (height < 2)
{
bucketCount = rowCount;
long preValue = sinkList[0];
int count = 1;
int distCount = 1;
for (int i = 1; i < rowCount; i++)
{
var curValue = sinkList[i];
if (curValue == preValue)
{
count++;
}
else
{
if (count > 1)
{
popBucketCount += count;
popValueCount++;
}
statistics.Histogram.Add(preValue, new Tuple<double, bool>(count, count > 1));
count = 1;
preValue = curValue;
distCount++;
}
}
if (count > 1)
{
popBucketCount += count;
popValueCount++;
}
statistics.Histogram.Add(preValue, new Tuple<double, bool>(count, count > 1));
statistics.MaxValue = preValue;
// Simple Denstity
//statistics.Density = 1.0 / distCount;
// Advanced Density
statistics.Density = bucketCount == popBucketCount
? 0
: 1.0 * (bucketCount - popBucketCount) / bucketCount / (distCount - popValueCount);
}
// Generate a Height-balanced Histogram
else
{
long preValue = sinkList[0];
int count = 0;
int distCount = 1;
for (int i = 1; i < rowCount; i++)
{
if (i % height == height - 1)
{
bucketCount++;
var curValue = sinkList[i];
if (curValue == preValue)
count += height;
else
{
distCount++;
if (count > height)
{
popBucketCount += count / height;
popValueCount++;
}
//count = count == 0 ? height : count;
statistics.Histogram.Add(preValue, new Tuple<double, bool>(count, count > height));
preValue = curValue;
count = height;
}
}
}
if (count > height)
{
popBucketCount += count / height;
popValueCount++;
}
statistics.Histogram.Add(preValue, new Tuple<double, bool>(count, count > height));
statistics.MaxValue = preValue;
// Simple Density
//statistics.Density = 1.0 / distCount;
// Advanced Density
statistics.Density = bucketCount == popBucketCount
? 0
: 1.0 * (bucketCount - popBucketCount) / bucketCount / (distCount - popValueCount);
}
_context.AddEdgeStatistics(edge, statistics);
}
public void AddEdgeStatistics(MatchEdge edge, ColumnStatistics statistics)
{
_edgeStatisticses.Add(edge, statistics);
}
/// <summary>
/// Merger Two Histograms
/// </summary>
/// <param name="curStatistics"></param>
/// <param name="newStatistics"></param>
/// <param name="currentJoin"></param>
/// <returns></returns>
internal static ColumnStatistics UpdateHistogram(ColumnStatistics curStatistics, ColumnStatistics newStatistics)
{
if (curStatistics == null)
return newStatistics;
else if (newStatistics == null)
return curStatistics;
var resHistogram = new Dictionary<long, Tuple<double, bool>>();
var curHistogram = curStatistics.Histogram;
var newHistogram = newStatistics.Histogram;
if (!curHistogram.Any())
{
return new ColumnStatistics
{
Density = newStatistics.Density,
Histogram = newHistogram,
Selectivity = curStatistics.Selectivity * newStatistics.Selectivity,
};
}
if (!newHistogram.Any())
{
return new ColumnStatistics
{
Density = curStatistics.Density,
Histogram = curHistogram,
Selectivity = curStatistics.Selectivity * newStatistics.Selectivity,
};
}
var curNotPopularCount = 0.0;
var newNotPopularCount = 0.0;
var curDefaultRow = curStatistics.Density * curStatistics.RowCount;
var newDefaultRow = newStatistics.Density * newStatistics.RowCount;
IEnumerator<KeyValuePair<long, Tuple<double, bool>>> newEntry = null;
bool fisrstMatch = false;
bool newHistogramEnd = false;
double resRowCount = 0.0;
List<long> notPopularValues = new List<long>();
foreach (var entry in curHistogram)
{
if (!fisrstMatch)
{
if (newHistogram.ContainsKey(entry.Key))
{
fisrstMatch = true;
var entry1 = entry;
newEntry = newHistogram.SkipWhile(e => e.Key != entry1.Key).GetEnumerator();
newEntry.MoveNext();
if (!entry.Value.Item2)
curNotPopularCount -= entry.Value.Item1;
if (!newEntry.Current.Value.Item2)
newNotPopularCount -= newEntry.Current.Value.Item1;
}
}
if (fisrstMatch)
{
if (newHistogramEnd || entry.Key < newEntry.Current.Key)
{
var curTuple = entry.Value;
if (curTuple.Item2 == true)
{
var tmpCount = curTuple.Item1 * newDefaultRow;
resRowCount += tmpCount;
resHistogram.Add(entry.Key, new Tuple<double, bool>(tmpCount, true));
}
else
{
notPopularValues.Add(entry.Key);
curNotPopularCount += curTuple.Item1;
resHistogram.Add(entry.Key, null);
}
}
else if (entry.Key > newEntry.Current.Key)
{
while (entry.Key > newEntry.Current.Key)
{
var newTuple = newEntry.Current.Value;
if (newTuple.Item2 == true)
{
var tmpCount = newTuple.Item1 * curDefaultRow;
resRowCount += tmpCount;
resHistogram.Add(newEntry.Current.Key, new Tuple<double, bool>(tmpCount, true));
}
else
{
notPopularValues.Add(newEntry.Current.Key);
newNotPopularCount += newTuple.Item1;
resHistogram.Add(newEntry.Current.Key, null);
}
if (!newEntry.MoveNext())
{
newHistogramEnd = true;
break;
}
}
if (newHistogramEnd)
{
break;
}
}
else
{
var curTuple = entry.Value;
var newTuple = newEntry.Current.Value;
if (curTuple.Item2 == false && newTuple.Item2 == false)
{
notPopularValues.Add(entry.Key);
curNotPopularCount += curTuple.Item1;
newNotPopularCount += newTuple.Item1;
resHistogram.Add(entry.Key, null);
}
else
{
var count1 = curTuple.Item2 ? curTuple.Item1 : curDefaultRow;
var count2 = newTuple.Item2 ? newTuple.Item1 : newDefaultRow;
var tmpCount = count1 * count2;
resRowCount += tmpCount;
resHistogram.Add(entry.Key, new Tuple<double, bool>(tmpCount, true));
}
if (!newEntry.MoveNext())
{
newHistogramEnd = true;
}
}
}
}
double density = -1;
if (notPopularValues.Any())
{
var resDefaultRow = curNotPopularCount * newNotPopularCount *
Math.Min(curDefaultRow / curNotPopularCount, newDefaultRow / newNotPopularCount);
resRowCount += resDefaultRow;
resDefaultRow = resDefaultRow / notPopularValues.Count;
density = resDefaultRow / resRowCount;
foreach (var value in notPopularValues)
{
resHistogram[value] = new Tuple<double, bool>(resDefaultRow, false);
}
}
return new ColumnStatistics
{
Histogram = resHistogram,
Density = density < 0 ? Math.Max(curStatistics.Density, newStatistics.Density) : density,
MaxValue = Math.Max(curStatistics.MaxValue, newStatistics.MaxValue),
RowCount = resRowCount,
Selectivity = resRowCount / (curStatistics.RowCount * newStatistics.RowCount),
};
}
public void AddEdgeStatistics(MatchEdge edge, ColumnStatistics statistics)
{
_edgeStatisticses.Add(edge, statistics);
}