private WBooleanExpression ConstructJoinCondition(
CandidateJoinUnit candidateTree,
IMatchJoinStatisticsCalculator statisticsCalculator,
GraphMetaData metaData,
out double joinSelectivity,
out double sqlEstimatedJoinSelectivity)
{
joinSelectivity = 1.0;
sqlEstimatedJoinSelectivity = 1.0;
var root = candidateTree.TreeRoot;
WBooleanExpression joinCondition = null;
string nodeName = "";
// Update Nodes
if (MaterializedNodeSplitCount.ContainsKey(root))
{
MaterializedNodeSplitCount[root]++;
nodeName = 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;
if (!Nodes.Contains(root))
{
Nodes.Add(root);
}
MaterializedNodeSplitCount[root] = 0;
}
List <double> densityList = new List <double>();
List <MatchEdge> inEdges;
if (UnmaterializedNodeMapping.TryGetValue(root, out inEdges))
{
var firstEdge = inEdges.First();
bool materialized = EdgeMaterilizedDict[firstEdge];
UnmaterializedNodeMapping.Remove(root);
joinSelectivity *= 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
});
densityList.Add(root.GlobalNodeIdDensity);
}
// Component unmaterialized edge to root
else
{
Statistics statistics = null;
foreach (var edge in inEdges)
{
// Update component table
TableRef = SpanTableRef(TableRef, edge, GetNodeRefName(edge.SourceNode), metaData);
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
});
double selectivity;
statistics = Statistics.UpdateHistogram(statistics,
edge.Statistics, out selectivity);
joinSelectivity *= selectivity;
densityList.Add(root.GlobalNodeIdDensity);
}
SinkNodeStatisticsDict[root] = statistics;
}
}
var jointEdges = candidateTree.MaterializedEdges;
foreach (var jointEdge in jointEdges)
{
EdgeMaterilizedDict[jointEdge] = true;
var sinkNode = jointEdge.SinkNode;
// Leaf to component materialized node
if (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
});
Statistics sinkNodeStatistics;
if (!SinkNodeStatisticsDict.TryGetValue(sinkNode, out sinkNodeStatistics))
{
sinkNodeStatistics = null;
joinSelectivity *= 1.0 / sinkNode.TableRowCount;
}
double selectivity;
var statistics = Statistics.UpdateHistogram(sinkNodeStatistics,
jointEdge.Statistics, out selectivity);
joinSelectivity *= selectivity;
SinkNodeStatisticsDict[sinkNode] = statistics;
densityList.Add(sinkNode.GlobalNodeIdDensity);
}
// Leaf to component unmaterialized node
else
{
inEdges = UnmaterializedNodeMapping[sinkNode];
var firstEdge = inEdges.First();
bool materlizedEdge = 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
});
densityList.Add(Statistics.DefaultDensity);
double selectivity;
var statistics = Statistics.UpdateHistogram(SinkNodeStatisticsDict[sinkNode],
jointEdge.Statistics, out selectivity);
joinSelectivity *= selectivity;
SinkNodeStatisticsDict[sinkNode] = statistics;
}
// Leaf to unmaterialized leaf
else
{
Statistics compSinkNodeStatistics = null;
foreach (var inEdge in inEdges)
{
TableRef = SpanTableRef(TableRef, inEdge, GetNodeRefName(inEdge.SourceNode), metaData);
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
});
densityList.Add(Statistics.DefaultDensity);
double selectivity;
var leafToLeafStatistics = statisticsCalculator.GetLeafToLeafStatistics(jointEdge, inEdge,
out selectivity);
joinSelectivity *= selectivity;
compSinkNodeStatistics =
Statistics.UpdateHistogram(compSinkNodeStatistics,
inEdge.Statistics, out selectivity);
}
SinkNodeStatisticsDict[sinkNode] = compSinkNodeStatistics;
}
}
}
var unmatEdges = candidateTree.UnmaterializedEdges;
foreach (var unmatEdge in unmatEdges)
{
EdgeMaterilizedDict[unmatEdge] = false;
if (!Nodes.Contains(unmatEdge.SinkNode))
{
Nodes.Add(unmatEdge.SinkNode);
}
var sinkNodeInEdges = UnmaterializedNodeMapping.GetOrCreate(unmatEdge.SinkNode);
sinkNodeInEdges.Add(unmatEdge);
}
// Calculate Estimated Join Selectivity & Estimated Node Size
densityList.Sort();
for (int i = densityList.Count - 1; i >= 0; i--)
{
sqlEstimatedJoinSelectivity *= Math.Sqrt(sqlEstimatedJoinSelectivity) * densityList[i];
}
return(joinCondition);
}
/// <summary>
/// Calculate join costs and update components using optimal join method & order
/// </summary>
/// <param name="nodeUnitCandidate"></param>
/// <param name="joinCondition"></param>
/// <param name="joinSelectivity"></param>
/// <param name="estimatedSelectivity"></param>
/// <returns></returns>
private void ConstructPhysicalJoinAndUpdateCost(
CandidateJoinUnit nodeUnitCandidate,
WBooleanExpression joinCondition,
double joinSelectivity,
double estimatedSelectivity,
GraphMetaData metaData)
{
var nodeDegrees = nodeUnitCandidate.EdgeDegrees;
var nodeUnitSize = nodeUnitCandidate.TreeRoot.EstimatedRows * nodeDegrees;
var estimatedNodeUnitSize = nodeUnitCandidate.TreeRoot.EstimatedRows *
nodeUnitCandidate.SqlEstimatedEdgeDegrees;
var componentSize = Cardinality;
var estimatedCompSize = SqlEstimatedSize;
var node = nodeUnitCandidate.TreeRoot;
// If the node is already in the component, then only multiply the degree to get the size
double nodeUnitActualSize;
double newCompEstSize;
if (MaterializedNodeSplitCount[node] > 0)
{
nodeUnitActualSize = nodeDegrees;
var cEstEdge = Math.Pow(1000, EdgeMaterilizedDict.Count(e => !e.Value));
var cSize = SqlEstimatedSize / cEstEdge;
var nSize = node.EstimatedRows;
if (nSize > cSize)
{
newCompEstSize = estimatedNodeUnitSize * cEstEdge * estimatedSelectivity;
}
else
{
newCompEstSize = SqlEstimatedSize * Math.Pow(1000, nodeUnitCandidate.UnmaterializedEdges.Count) * estimatedSelectivity;
}
}
else
{
nodeUnitActualSize = nodeUnitSize;
newCompEstSize = SqlEstimatedSize * estimatedNodeUnitSize * estimatedSelectivity;
}
newCompEstSize = newCompEstSize < 1.0 ? 1.0 : newCompEstSize;
bool firstJoin = MaterializedNodeSplitCount.Count == 2 &&
MaterializedNodeSplitCount.All(e => e.Value == 0);
// Update TableRef
double loopJoinOuterThreshold = 1e4; //1e6;
double sizeFactor = 5; //1000;
double maxMemory = 1e8;
double loopCost = componentSize * Math.Log(nodeUnitCandidate.TreeRoot.EstimatedRows, 512) * 0.20;
double hashCost = componentSize + nodeUnitSize;
double cost;
// Loop Join
if (
nodeUnitCandidate.MaterializedEdges.Count == 0 && // the joins are purely leaf to sink join
(
//componentSize < loopJoinOuterThreshold || // the outer table is relatively small
loopCost < hashCost ||
(DeltaMemory + componentSize > maxMemory && DeltaMemory + nodeUnitSize > maxMemory) // memory is in pressure
)
)
{
if (firstJoin)
{
RightestTableRefSize = nodeUnitCandidate.TreeRoot.EstimatedRows;
RightestTableAlias = GetNodeRefName(node);
}
TotalMemory = DeltaMemory;
SqlEstimatedTotalMemory = SqlEstimatedDeltaMemory;
//joinTable.JoinHint = JoinHint.Loop;
SqlEstimatedSize = estimatedCompSize * estimatedNodeUnitSize /
nodeUnitCandidate.TreeRoot.TableRowCount;
cost = loopCost; //componentSize*Math.Log(nodeUnitCandidate.TreeRoot.EstimatedRows, 512);
TableRef = new WParenthesisTableReference
{
Table = new WQualifiedJoin
{
FirstTableRef = TableRef,
SecondTableRef =
nodeUnitCandidate.ToTableReference(GetNodeRefName(nodeUnitCandidate.TreeRoot), metaData),
JoinCondition = joinCondition,
QualifiedJoinType = QualifiedJoinType.Inner,
JoinHint = JoinHint.Loop
}
};
}
// Hash Join
else
{
cost = hashCost;//componentSize + nodeUnitSize;
WBooleanExpression adjustedJoincondition;
double adjustedSqlEstimatedSize;
WTableReference buildTableReference;
WTableReference probeTableReference;
if (firstJoin)
{
var nodeInComp = MaterializedNodeSplitCount.Keys.First(e => e != node);
if (nodeUnitSize < componentSize)
{
buildTableReference = AdjustEstimation(nodeUnitCandidate, GetNodeRefName(node), metaData, out adjustedJoincondition,
out adjustedSqlEstimatedSize);
probeTableReference = TableRef;
TotalMemory = DeltaMemory = nodeUnitSize;
SqlEstimatedTotalMemory = SqlEstimatedDeltaMemory = estimatedNodeUnitSize;
RightestTableRefSize = nodeInComp.EstimatedRows;
RightestTableAlias = GetNodeRefName(nodeInComp);
}
else
{
RightestTableRefSize = nodeInComp.EstimatedRows;
RightestTableAlias = GetNodeRefName(nodeInComp);
buildTableReference = AdjustEstimation(this, out adjustedJoincondition, out adjustedSqlEstimatedSize);
probeTableReference =
nodeUnitCandidate.ToTableReference(GetNodeRefName(nodeUnitCandidate.TreeRoot), metaData);
TotalMemory = DeltaMemory = componentSize;
SqlEstimatedTotalMemory = SqlEstimatedDeltaMemory = SqlEstimatedSize;
RightestTableRefSize = nodeUnitCandidate.TreeRoot.EstimatedRows;
RightestTableAlias = GetNodeRefName(node);
}
}
// Left Deep
else if (componentSize * sizeFactor < nodeUnitSize)
{
// Adjust estimation in sql server
buildTableReference = AdjustEstimation(this, out adjustedJoincondition, out adjustedSqlEstimatedSize);
probeTableReference =
nodeUnitCandidate.ToTableReference(GetNodeRefName(nodeUnitCandidate.TreeRoot), metaData);
var curDeltaMemory = componentSize;
TotalMemory = DeltaMemory + curDeltaMemory;
DeltaMemory = curDeltaMemory;
var curDeltaEstimateMemory = SqlEstimatedSize;
SqlEstimatedTotalMemory = SqlEstimatedDeltaMemory + curDeltaEstimateMemory;
SqlEstimatedDeltaMemory = curDeltaEstimateMemory;
RightestTableAlias = GetNodeRefName(node);
RightestTableRefSize = nodeUnitCandidate.TreeRoot.EstimatedRows;
}
// Right Deep
else
{
buildTableReference = AdjustEstimation(nodeUnitCandidate, GetNodeRefName(node), metaData, out adjustedJoincondition,
out adjustedSqlEstimatedSize);
probeTableReference = TableRef;
TotalMemory += nodeUnitSize;
DeltaMemory = TotalMemory;
SqlEstimatedTotalMemory += estimatedNodeUnitSize;
SqlEstimatedDeltaMemory = SqlEstimatedTotalMemory;
}
newCompEstSize *= adjustedSqlEstimatedSize;
TableRef = new WParenthesisTableReference
{
Table =
new WQualifiedJoin
{
FirstTableRef = buildTableReference,
SecondTableRef = probeTableReference,
JoinCondition = WBooleanBinaryExpression.Conjunction(joinCondition, adjustedJoincondition),
QualifiedJoinType = QualifiedJoinType.Inner,
JoinHint = JoinHint.Hash
}
};
SqlEstimatedSize = newCompEstSize < 1.0 ? 1.0 : newCompEstSize;
}
//Update Size
Cardinality *= nodeUnitActualSize * joinSelectivity;
// Debug
#if DEBUG
//foreach (var item in MaterializedNodeSplitCount.Where(e => e.Key != node))
//{
// Trace.Write(item.Key.RefAlias + ",");
//}
//Trace.Write(node.RefAlias);
//Trace.Write(" Size:" + Cardinality + " Cost:" + cost);
//Trace.Write(" Method:" + ((TableRef as WParenthesisTableReference).Table as WQualifiedJoin).JoinHint);
//Trace.WriteLine(" --> Total Cost:" + Cost);
#endif
// Update Cost
Cost += cost;
}
