private List <string> PopulateAdjacencyListProperties(MatchEdge edge)
{
if (edge.EdgeType == WEdgeType.BothEdge)
{
return new List <string> {
GremlinKeyword.EdgeAdj, GremlinKeyword.ReverseEdgeAdj
}
}
;
//
// IsTraversalThroughPhysicalReverseEdge
//
if ((edge.EdgeType == WEdgeType.OutEdge && edge.IsReversed) ||
edge.EdgeType == WEdgeType.InEdge && !edge.IsReversed)
{
return new List <string> {
GremlinKeyword.ReverseEdgeAdj
}
}
;
else
{
return new List <string> {
GremlinKeyword.EdgeAdj
}
};
}
private static WColumnReferenceExpression GetNodeColumnReferenceExprFromLink(CompileLink link)
{
if (link is MatchEdge)
{
MatchEdge edge = link as MatchEdge;
if (edge.EdgeType == WEdgeType.OutEdge)
{
return(SqlUtil.GetColumnReferenceExpr(edge.LinkAlias,
edge.IsReversed ? GremlinKeyword.EdgeSinkV : GremlinKeyword.EdgeSourceV));
}
else if (edge.EdgeType == WEdgeType.InEdge)
{
return(SqlUtil.GetColumnReferenceExpr(edge.LinkAlias,
edge.IsReversed ? GremlinKeyword.EdgeSourceV : GremlinKeyword.EdgeSinkV));
}
else
{
return(SqlUtil.GetColumnReferenceExpr(edge.LinkAlias, GremlinKeyword.EdgeOtherV));
}
}
else if (link is PredicateLink)
{
PredicateLink predicateLink = link as PredicateLink;
if (predicateLink.BooleanExpression is WEdgeVertexBridgeExpression)
{
return((predicateLink.BooleanExpression as WEdgeVertexBridgeExpression).FirstExpr as WColumnReferenceExpression);
}
}
throw new QueryCompilationException("Cannot support " + link + " as a traversal link or an edge");
}
/// <summary>
/// Generate the Table-Valued Function by the edge given the node alias
/// </summary>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <returns></returns>
private static WTableReference EdgeToTableReference(MatchEdge edge, string nodeAlias)
{
var edgeColumn = edge.EdgeColumn;
var edgeIdentifiers = edge.EdgeColumn.MultiPartIdentifier.Identifiers;
if (nodeAlias != edgeIdentifiers.First().Value)
{
var identifiers = new List <Identifier>(edgeIdentifiers);
identifiers.RemoveAt(0);
identifiers.Insert(0, new Identifier
{
Value = nodeAlias
});
edgeColumn = new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier
{
Identifiers = identifiers
}
};
}
var columnName = edgeIdentifiers.Last().Value;
var deColIdentifiers = new Identifier[]
{
edgeColumn.MultiPartIdentifier.Identifiers.First(),
new Identifier {
Value = columnName + "DeleteCol"
}
};
var decoderFunction = new Identifier
{
Value = edge.SourceNode.TableObjectName.SchemaIdentifier.Value + '_' +
edge.SourceNode.TableObjectName.BaseIdentifier.Value + '_' +
columnName + '_' +
"Decoder",
};
var tableRef = new WSchemaObjectFunctionTableReference
{
SchemaObject = new WSchemaObjectName(
new Identifier {
Value = "dbo"
},
decoderFunction),
Parameters = new List <WScalarExpression>
{
edgeColumn,
new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier(deColIdentifiers)
}
},
Alias = new Identifier
{
Value = edge.EdgeAlias,
}
};
return(tableRef);
}
/// <summary>
/// Span the table given the edge using cross apply
/// </summary>
/// <param name="tableRef"></param>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <returns></returns>
public static WTableReference SpanTableRef(WTableReference tableRef, MatchEdge edge, string nodeAlias)
{
tableRef = new WUnqualifiedJoin
{
FirstTableRef = tableRef,
SecondTableRef = EdgeToTableReference(edge, nodeAlias),
UnqualifiedJoinType = UnqualifiedJoinType.CrossApply,
};
return(tableRef);
}
/// <summary>
/// Span the table given the edge using cross apply
/// </summary>
/// <param name="tableRef"></param>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <returns></returns>
public WTableReference SpanTableRef(WTableReference tableRef, MatchEdge edge, string nodeAlias, GraphMetaData metaData)
{
tableRef = new WUnqualifiedJoin
{
FirstTableRef = tableRef,
SecondTableRef = edge.ToSchemaObjectFunction(nodeAlias, metaData),
UnqualifiedJoinType = UnqualifiedJoinType.CrossApply,
};
return(tableRef);
}
public bool TryGetEdge(string key, out MatchEdge edge)
{
foreach (var subGraph in ConnectedSubGraphs)
{
if (subGraph.Edges.TryGetValue(key, out edge))
{
return(true);
}
}
edge = null;
return(false);
}
public void AddEdgeReference(MatchEdge edge)
{
var edgeAlias = edge.EdgeAlias;
if (_nodeTableDictionary.ContainsKey(edgeAlias) || _edgeDictionary.ContainsKey(edgeAlias))
{
throw new GraphViewException("Duplicate Alias");
}
_edgeDictionary.Add(edgeAlias,
new Tuple <WSchemaObjectName, WColumnReferenceExpression>(edge.SourceNode.NodeTableObjectName,
edge.EdgeColumn));
}
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 Statistics GetLeafToLeafStatistics(MatchEdge nodeEdge, MatchEdge componentEdge, out double selectivity)
{
var edgeTuple = new Tuple <string, string>(nodeEdge.EdgeAlias, componentEdge.EdgeAlias);
Tuple <Statistics, double> edgeStatisticsTuple;
if (_leafToLeafStatistics.TryGetValue(edgeTuple, out edgeStatisticsTuple))
{
selectivity = edgeStatisticsTuple.Item2;
return(edgeStatisticsTuple.Item1);
}
var mergedStatistics = Statistics.UpdateHistogram(nodeEdge.Statistics, componentEdge.Statistics,
out selectivity);
_leafToLeafStatistics[edgeTuple] = new Tuple <Statistics, double>(mergedStatistics, selectivity);
return(mergedStatistics);
}
/// <summary>
/// Constructs the graph pattern specified by the MATCH clause.
/// The graph pattern may consist of multiple fully-connected sub-graphs.
/// </summary>
/// <param name="query">The SELECT query block</param>
/// <returns>A graph object contains all the connected componeents</returns>
private MatchGraph ConstructGraph(WSelectQueryBlock query)
{
if (query == null || query.MatchClause == null)
return null;
var unionFind = new UnionFind();
var edgeColumnToAliasesDict = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
var pathDictionary = new Dictionary<string, MatchPath>(StringComparer.OrdinalIgnoreCase);
var matchClause = query.MatchClause;
var nodes = new Dictionary<string, MatchNode>(StringComparer.OrdinalIgnoreCase);
var connectedSubGraphs = new List<ConnectedComponent>();
var subGrpahMap = new Dictionary<string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
var parent = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
unionFind.Parent = parent;
// Constructs the graph pattern specified by the path expressions in the MATCH clause
foreach (var path in matchClause.Paths)
{
var index = 0;
MatchEdge preEdge = null;
for (var count = path.PathEdgeList.Count; index < count; ++index)
{
var currentNodeTableRef = path.PathEdgeList[index].Item1;
var currentEdgeColumnRef = path.PathEdgeList[index].Item2;
var currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
var nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
var nextNodeExposedName = nextNodeTableRef.BaseIdentifier.Value;
var patternNode = nodes.GetOrCreate(currentNodeExposedName);
if (patternNode.NodeAlias == null)
{
patternNode.NodeAlias = currentNodeExposedName;
patternNode.Neighbors = new List<MatchEdge>();
patternNode.External = false;
var nodeTable = _context[currentNodeExposedName] as WNamedTableReference;
if (nodeTable != null)
{
patternNode.NodeTableObjectName = nodeTable.TableObjectName;
if (patternNode.NodeTableObjectName.SchemaIdentifier == null)
patternNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
string edgeAlias = currentEdgeColumnRef.Alias;
if (edgeAlias == null)
{
var currentEdgeName = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value;
edgeAlias = string.Format("{0}_{1}_{2}", currentNodeExposedName, currentEdgeName,
nextNodeExposedName);
if (edgeColumnToAliasesDict.ContainsKey(currentEdgeName))
{
edgeColumnToAliasesDict[currentEdgeName].Add(edgeAlias);
}
else
{
edgeColumnToAliasesDict.Add(currentEdgeName, new List<string> { edgeAlias });
}
}
Identifier edgeIdentifier = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last();
string schema = patternNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
string nodeTableName = patternNode.NodeTableObjectName.BaseIdentifier.Value;
string bindTableName =
_context.EdgeNodeBinding[
new Tuple<string, string>(nodeTableName.ToLower(), edgeIdentifier.Value.ToLower())].ToLower();
MatchEdge edge;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
edge = new MatchEdge
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
};
_context.AddEdgeReference(edge);
}
else
{
MatchPath matchPath = new MatchPath
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict
};
_context.AddEdgeReference(matchPath);
pathDictionary[edgeAlias] = matchPath;
edge = matchPath;
}
if (preEdge != null)
{
preEdge.SinkNode = patternNode;
}
preEdge = edge;
if (!parent.ContainsKey(currentNodeExposedName))
parent[currentNodeExposedName] = currentNodeExposedName;
if (!parent.ContainsKey(nextNodeExposedName))
parent[nextNodeExposedName] = nextNodeExposedName;
unionFind.Union(currentNodeExposedName, nextNodeExposedName);
patternNode.Neighbors.Add(edge);
}
var tailExposedName = path.Tail.BaseIdentifier.Value;
var tailNode = nodes.GetOrCreate(tailExposedName);
if (tailNode.NodeAlias == null)
{
tailNode.NodeAlias = tailExposedName;
tailNode.Neighbors = new List<MatchEdge>();
var nodeTable = _context[tailExposedName] as WNamedTableReference;
if (nodeTable != null)
{
tailNode.NodeTableObjectName = nodeTable.TableObjectName;
if (tailNode.NodeTableObjectName.SchemaIdentifier == null)
tailNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
if (preEdge != null)
preEdge.SinkNode = tailNode;
}
// Puts nodes into subgraphs
foreach (var node in nodes)
{
string root = unionFind.Find(node.Key);
if (!subGrpahMap.ContainsKey(root))
{
var subGraph = new ConnectedComponent();
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGrpahMap[root] = subGraph;
connectedSubGraphs.Add(subGraph);
subGraph.IsTailNode[node.Value] = false;
}
else
{
var subGraph = subGrpahMap[root];
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGraph.IsTailNode[node.Value] = false;
}
}
var graph = new MatchGraph
{
ConnectedSubGraphs = connectedSubGraphs,
};
unionFind.Parent = null;
// When an edge in the MATCH clause is not associated with an alias,
// assigns to it a default alias: sourceAlias_EdgeColumnName_sinkAlias.
// Also rewrites edge attributes anywhere in the query that can be bound to this default alias.
var replaceTableRefVisitor = new ReplaceEdgeReferenceVisitor();
replaceTableRefVisitor.Invoke(query, edgeColumnToAliasesDict);
// Rematerializes node tables in the MATCH clause which are defined in the upper-level context
// and join them with the upper-level table references.
RematerilizeExtrenalNodeTableReference(query, nodes);
// Transforms the path reference in the SELECT elements into a
// scalar function to display path information.
TransformPathInfoDisplaySelectElement(query, pathDictionary);
return graph;
}
/// <summary>
/// Constructs the graph pattern specified by the MATCH clause.
/// The graph pattern may consist of multiple fully-connected sub-graphs.
/// </summary>
/// <param name="query">The SELECT query block</param>
/// <returns>A graph object contains all the connected componeents</returns>
private MatchGraph ConstructGraph(WSelectQueryBlock query)
{
if (query == null || query.MatchClause == null)
return null;
var columnsOfNodeTables = _graphMetaData.ColumnsOfNodeTables;
var nodeViewMapping = _graphMetaData.NodeViewMapping;
var unionFind = new UnionFind();
var edgeColumnToAliasesDict = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
var pathDictionary = new Dictionary<string, MatchPath>(StringComparer.OrdinalIgnoreCase);
var reversedEdgeDict = new Dictionary<string, MatchEdge>();
var matchClause = query.MatchClause;
var nodes = new Dictionary<string, MatchNode>(StringComparer.OrdinalIgnoreCase);
var connectedSubGraphs = new List<ConnectedComponent>();
var subGrpahMap = new Dictionary<string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
var parent = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
unionFind.Parent = parent;
// Constructs the graph pattern specified by the path expressions in the MATCH clause
foreach (var path in matchClause.Paths)
{
var index = 0;
MatchEdge preEdge = null;
for (var count = path.PathEdgeList.Count; index < count; ++index)
{
var currentNodeTableRef = path.PathEdgeList[index].Item1;
var currentEdgeColumnRef = path.PathEdgeList[index].Item2;
var currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
var nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
var nextNodeExposedName = nextNodeTableRef.BaseIdentifier.Value;
var patternNode = nodes.GetOrCreate(currentNodeExposedName);
if (patternNode.NodeAlias == null)
{
patternNode.NodeAlias = currentNodeExposedName;
patternNode.Neighbors = new List<MatchEdge>();
patternNode.External = false;
var nodeTable = _context[currentNodeExposedName] as WNamedTableReference;
if (nodeTable != null)
{
patternNode.NodeTableObjectName = nodeTable.TableObjectName;
if (patternNode.NodeTableObjectName.SchemaIdentifier == null)
patternNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
Identifier edgeIdentifier = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last();
string schema = patternNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
string nodeTableName = patternNode.NodeTableObjectName.BaseIdentifier.Value;
string bindTableName =
_context.EdgeNodeBinding[
new Tuple<string, string>(nodeTableName.ToLower(), edgeIdentifier.Value.ToLower())].ToLower();
var bindNodeTableObjName = new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
);
var edgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(bindNodeTableObjName)][
currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value];
string edgeAlias = currentEdgeColumnRef.Alias;
//string revEdgeAlias = edgeAlias;
bool isReversed = path.IsReversed || edgeColumn.EdgeInfo.IsReversedEdge;
string currentRevEdgeName = null;
// get original edge name
var currentEdgeName = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().Value;
var originalSourceName = isReversed ?
(_context[nextNodeExposedName] as WNamedTableReference).TableObjectName.BaseIdentifier.Value
: (_context[currentNodeExposedName] as WNamedTableReference).TableObjectName.BaseIdentifier.Value;
if (isReversed)
{
var i = currentEdgeName.IndexOf(originalSourceName, StringComparison.OrdinalIgnoreCase) +
originalSourceName.Length;
currentRevEdgeName = currentEdgeName.Substring(i + 1,
currentEdgeName.Length - "Reversed".Length - i - 1);
}
else
{
var srcTuple = WNamedTableReference.SchemaNameToTuple(patternNode.NodeTableObjectName);
// [nodeView]-[edge]->[node/nodeView]
if (edgeColumn.Role == WNodeTableColumnRole.Edge && nodeViewMapping.ContainsKey(srcTuple))
{
var physicalNodeName =
_context.EdgeNodeBinding[new Tuple<string, string>(srcTuple.Item2, currentEdgeName.ToLower())];
currentRevEdgeName = physicalNodeName + "_" + currentEdgeName + "Reversed";
}
else
{
currentRevEdgeName = originalSourceName + "_" + currentEdgeName + "Reversed";
}
}
if (edgeAlias == null)
{
edgeAlias = !isReversed
? string.Format("{0}_{1}_{2}", currentNodeExposedName, currentEdgeName, nextNodeExposedName)
: string.Format("{0}_{1}_{2}", nextNodeExposedName, currentRevEdgeName, currentNodeExposedName);
//when the current edge is a reversed edge, the key should still be the original edge name
//e.g.: TestDeleteEdgeWithTableAlias
var edgeNameKey = isReversed ? currentRevEdgeName : currentEdgeName;
if (edgeColumnToAliasesDict.ContainsKey(edgeNameKey))
{
edgeColumnToAliasesDict[edgeNameKey].Add(edgeAlias);
}
else
{
edgeColumnToAliasesDict.Add(edgeNameKey, new List<string> { edgeAlias });
}
}
MatchEdge edge, revEdge;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
var isEdgeView = edgeColumn.Role == WNodeTableColumnRole.EdgeView;
var hasRevEdge = edgeColumn.EdgeInfo.HasReversedEdge;
edge = new MatchEdge
{
IsEdgeView = isEdgeView,
IsReversedEdge = false,
HasReversedEdge = hasRevEdge,
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName = bindNodeTableObjName,
};
_context.AddEdgeReference(edge);
if (hasRevEdge)
{
revEdge = new MatchEdge
{
IsEdgeView = isEdgeView,
IsReversedEdge = true,
SinkNode = patternNode,
EdgeColumn = new WEdgeColumnReferenceExpression()
{
ColumnType = currentEdgeColumnRef.ColumnType,
Alias = currentEdgeColumnRef.Alias,
MaxLength = currentEdgeColumnRef.MaxLength,
MinLength = currentEdgeColumnRef.MinLength,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict,
MultiPartIdentifier = new WMultiPartIdentifier(new Identifier()
{
QuoteType = currentEdgeColumnRef.MultiPartIdentifier.Identifiers.Last().QuoteType,
Value = currentRevEdgeName,
}),
},
EdgeAlias = edgeAlias,
//EdgeAlias = revEdgeAlias,
};
reversedEdgeDict[edge.EdgeAlias] = revEdge;
}
}
else
{
MatchPath matchPath = new MatchPath
{
SourceNode = patternNode,
EdgeColumn = currentEdgeColumnRef,
EdgeAlias = edgeAlias,
BindNodeTableObjName =
new WSchemaObjectName(
new Identifier {Value = schema},
new Identifier {Value = bindTableName}
),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict
};
_context.AddEdgeReference(matchPath);
pathDictionary[edgeAlias] = matchPath;
edge = matchPath;
}
if (preEdge != null)
{
preEdge.SinkNode = patternNode;
if (preEdge.HasReversedEdge)
{
//var preSourceNode = preEdge.SourceNode;
var preEdgeBindNodeTableObjName = preEdge.BindNodeTableObjName;
var preEdgeColName = preEdge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value;
var preEdgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(preEdgeBindNodeTableObjName)][
preEdgeColName];
var isEdgeView = preEdgeColumn.Role == WNodeTableColumnRole.EdgeView;
var isNodeView =
_graphMetaData.NodeViewMapping.ContainsKey(
WNamedTableReference.SchemaNameToTuple(patternNode.NodeTableObjectName));
reversedEdgeDict[preEdge.EdgeAlias].SourceNode = patternNode;
// [node/nodeView]-[edgeView]->[node/nodeView]
if (isEdgeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = preEdgeBindNodeTableObjName;
}
// [node/nodeView]-[edge]->[nodeView]
else if (!isEdgeView && isNodeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = "dbo" },
new Identifier { Value = preEdgeColumn.EdgeInfo.SinkNodes.First() }
);
}
else
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = schema },
new Identifier { Value = bindTableName }
);
}
}
}
preEdge = edge;
if (!parent.ContainsKey(currentNodeExposedName))
parent[currentNodeExposedName] = currentNodeExposedName;
if (!parent.ContainsKey(nextNodeExposedName))
parent[nextNodeExposedName] = nextNodeExposedName;
unionFind.Union(currentNodeExposedName, nextNodeExposedName);
patternNode.Neighbors.Add(edge);
}
var tailExposedName = path.Tail.BaseIdentifier.Value;
var tailNode = nodes.GetOrCreate(tailExposedName);
if (tailNode.NodeAlias == null)
{
tailNode.NodeAlias = tailExposedName;
tailNode.Neighbors = new List<MatchEdge>();
var nodeTable = _context[tailExposedName] as WNamedTableReference;
if (nodeTable != null)
{
tailNode.NodeTableObjectName = nodeTable.TableObjectName;
if (tailNode.NodeTableObjectName.SchemaIdentifier == null)
tailNode.NodeTableObjectName.Identifiers.Insert(0, new Identifier {Value = "dbo"});
}
}
if (preEdge != null)
{
preEdge.SinkNode = tailNode;
if (preEdge.HasReversedEdge)
{
var schema = tailNode.NodeTableObjectName.SchemaIdentifier.Value.ToLower();
var nodeTableName = tailNode.NodeTableObjectName.BaseIdentifier.Value;
//var preSourceNode = preEdge.SourceNode;
var preEdgeBindNodeTableObjName = preEdge.BindNodeTableObjName;
var preEdgeColName = preEdge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value;
var preEdgeColumn =
columnsOfNodeTables[
WNamedTableReference.SchemaNameToTuple(preEdgeBindNodeTableObjName)][
preEdgeColName];
var isEdgeView = preEdgeColumn.Role == WNodeTableColumnRole.EdgeView;
var isNodeView =
_graphMetaData.NodeViewMapping.ContainsKey(
WNamedTableReference.SchemaNameToTuple(tailNode.NodeTableObjectName));
reversedEdgeDict[preEdge.EdgeAlias].SourceNode = tailNode;
// [node/nodeView]-[edgeView]->[node/nodeView]
if (isEdgeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = preEdgeBindNodeTableObjName;
}
// [node/nodeView]-[edge]->[nodeView]
else if (!isEdgeView && isNodeView)
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = "dbo" },
new Identifier { Value = preEdgeColumn.EdgeInfo.SinkNodes.First() }
);
}
else
{
reversedEdgeDict[preEdge.EdgeAlias].BindNodeTableObjName = new WSchemaObjectName(
new Identifier { Value = schema },
new Identifier { Value = nodeTableName.ToLower() }
);
}
}
}
}
// Puts nodes into subgraphs
foreach (var node in nodes)
{
string root = unionFind.Find(node.Key);
if (!subGrpahMap.ContainsKey(root))
{
var subGraph = new ConnectedComponent();
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGrpahMap[root] = subGraph;
connectedSubGraphs.Add(subGraph);
subGraph.IsTailNode[node.Value] = false;
}
else
{
var subGraph = subGrpahMap[root];
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGraph.IsTailNode[node.Value] = false;
}
}
var graph = new MatchGraph
{
ReversedEdgeDict = reversedEdgeDict,
ConnectedSubGraphs = connectedSubGraphs,
SourceNodeStatisticsDict = new Dictionary<Tuple<string, bool>, Statistics>(),
};
unionFind.Parent = null;
// When an edge in the MATCH clause is not associated with an alias,
// assigns to it a default alias: sourceAlias_EdgeColumnName_sinkAlias.
// Also rewrites edge attributes anywhere in the query that can be bound to this default alias.
var replaceTableRefVisitor = new ReplaceEdgeReferenceVisitor();
replaceTableRefVisitor.Invoke(query, edgeColumnToAliasesDict);
// Rematerializes node tables in the MATCH clause which are defined in the upper-level context
// and join them with the upper-level table references.
RematerilizeExtrenalNodeTableReference(query, nodes);
// Transforms the path reference in the SELECT elements into a
// scalar function to display path information.
TransformPathInfoDisplaySelectElement(query, pathDictionary);
return graph;
}
/// <summary>
/// Estimates the average degree of the edges and retrieve density value.
/// Send sa query to retrieve the varbinary of the sink in the edge sampling table with edge predicates,
/// then generates the statistics histogram for each edge
/// </summary>
private void RetrieveStatistics(MatchGraph graph)
{
if (graph == null) throw new ArgumentNullException("graph");
// Declare the parameters if any
var declareParameter = "";
if (_variables != null)
{
declareParameter = _variables.Aggregate(declareParameter,
(current, parameter) =>
current +
("DECLARE " + parameter.VariableName.Value + " " +
TsqlFragmentToString.DataType(parameter.DataType) + "\r\n"));
}
// Calculates the average degree
var sb = new StringBuilder();
bool first = true;
sb.Append("SELECT [Edge].*, [EdgeDegrees].[SampleRowCount], [EdgeDegrees].[AverageDegree] FROM");
sb.Append("(\n");
foreach (var edge in graph.ConnectedSubGraphs.SelectMany(subGraph => subGraph.Edges.Values))
{
if (!first)
sb.Append("\nUNION ALL\n");
else
{
first = false;
}
var tableObjectName = edge.SourceNode.NodeTableObjectName;
string schema = tableObjectName.SchemaIdentifier.Value.ToLower();
string tableName = tableObjectName.BaseIdentifier.Value.ToLower();
string edgeName = edge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value.ToLower();
string bindTableName = _context.EdgeNodeBinding[new Tuple<string, string>(tableName, edgeName)];
// Distinguished between path and edge
//var sinkColumnName = edge.IsPath ? "COUNT(Sink)" : "[dbo].[GraphViewUDFGlobalNodeIdEncoder](Sink)";
sb.Append(
string.Format(@"
SELECT '{0}' as TableSchema,
'{1}' as TableName,
'{2}' as ColumnName,
'{3}' as Alias,
[dbo].[GraphViewUDFGlobalNodeIdEncoder](Src) as Src,
[dbo].[GraphViewUDFGlobalNodeIdEncoder](Sink) as Sink,
0 as IsReversed,
NULL as OriginalEdgeAlias
FROM [{0}_{1}_{2}_Sampling] as [{3}]", schema,
bindTableName,
edgeName,
edge.EdgeAlias));
var predicatesExpr = edge.RetrievePredicatesExpression();
if (predicatesExpr!=null)
sb.AppendFormat("\n WHERE {0}", predicatesExpr);
MatchEdge revEdge;
if (graph.ReversedEdgeDict.TryGetValue(edge.EdgeAlias, out revEdge))
{
sb.Append("\nUNION ALL\n");
var isEdgeView = revEdge.IsEdgeView;
var revTableObjectName = revEdge.SourceNode.NodeTableObjectName;
var revSchema = revTableObjectName.SchemaIdentifier.Value.ToLower();
var revEdgeName = revEdge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value.ToLower();
var revBindTableName = revEdge.BindNodeTableObjName.Identifiers.Last().Value.ToLower();
var revSamplingTableName = revSchema + "_" + revBindTableName + "_" + revEdgeName;
var revSrcTuple = WNamedTableReference.SchemaNameToTuple(revEdge.BindNodeTableObjName);
//var revSinkTuple = WNamedTableReference.SchemaNameToTuple(revEdge.SinkNode.NodeTableObjectName);
var originalEdgeName = edge.EdgeColumn.MultiPartIdentifier.Identifiers.Last().Value.ToLower();
// [node/nodeView]-[edgeView]->[node/nodeView]
if (isEdgeView)
{
revEdgeName = revSrcTuple.Item2 + "_" + originalEdgeName + "Reversed";
revSamplingTableName = revSrcTuple.Item1 + "_" + revSrcTuple.Item2 + "_" + revEdgeName;
}
sb.Append(
string.Format(@"
SELECT '{0}' as TableSchema,
'{1}' as TableName,
'{2}' as ColumnName,
'{3}' as Alias,
[dbo].[GraphViewUDFGlobalNodeIdEncoder](Src) as Src,
[dbo].[GraphViewUDFGlobalNodeIdEncoder](Sink) as Sink,
1 as IsReversed,
'{4}' as OriginalEdgeAlias
FROM [{5}_Sampling] as [{3}]", revSchema,
revBindTableName,
revEdgeName,
revEdge.EdgeAlias,
edge.EdgeAlias,
revSamplingTableName));
var revPredicatesExpr = revEdge.RetrievePredicatesExpression();
if (revPredicatesExpr != null)
sb.AppendFormat("\n WHERE {0}", revPredicatesExpr);
}
}
sb.Append("\n) as Edge \n");
sb.Append(String.Format(@"
INNER JOIN
[{0}] as [EdgeDegrees]
ON
[EdgeDegrees].[TableSchema] = [Edge].[TableSchema]
AND [EdgeDegrees].[TableName] = [Edge].[TableName]
AND [EdgeDegrees].[ColumnName] = [Edge].[ColumnName]", GraphViewConnection.MetadataTables[3]));
using (var command = Tx.Connection.CreateCommand())
{
command.Transaction = Tx;
command.CommandText = declareParameter + sb.ToString();
using (var reader = command.ExecuteReader())
{
var srcNodeStatisticsDict = graph.SourceNodeStatisticsDict;
while (reader.Read())
{
MatchEdge edge = null;
bool isReversed = reader["isReversed"].ToString().Equals("1");
if (!isReversed && !graph.TryGetEdge(reader["Alias"].ToString(), out edge))
throw new GraphViewException(string.Format("Edge {0} not exists", reader["Alias"].ToString()));
if (isReversed && !graph.TryGetEdge(reader["OriginalEdgeAlias"].ToString(), out edge))
throw new GraphViewException(string.Format("Edge {0} not exists", reader["OriginalEdgeAlias"].ToString()));
if (isReversed)
edge = graph.ReversedEdgeDict[edge.EdgeAlias];
var srcBytes = reader["Src"] as byte[];
var cursor = 0;
if (srcBytes != null)
{
var srcList = new List<long>();
while (cursor < srcBytes.Length)
{
var src = BitConverter.ToInt64(srcBytes, cursor);
cursor += 8;
srcList.Add(src);
}
var tmpEdge = new MatchEdge();
Statistics.UpdateEdgeHistogram(tmpEdge, srcList);
srcNodeStatisticsDict[new Tuple<string, bool>(edge.EdgeAlias, isReversed)] = tmpEdge.Statistics;
}
else
srcNodeStatisticsDict[new Tuple<string, bool>(edge.EdgeAlias, isReversed)] = null;
var sinkBytes = reader["Sink"] as byte[];
if (sinkBytes == null)
{
edge.Statistics = new Statistics
{
Density = 0,
Histogram = new Dictionary<long, Tuple<double, bool>>(),
MaxValue = 0,
RowCount = 0,
//Selectivity = 1.0
};
continue;
}
List<long> sinkList = new List<long>();
cursor = 0;
while (cursor < sinkBytes.Length)
{
var sink = BitConverter.ToInt64(sinkBytes, cursor);
cursor += 8;
sinkList.Add(sink);
}
Statistics.UpdateEdgeHistogram(edge, sinkList);
edge.AverageDegree = Convert.ToDouble(reader["AverageDegree"])*sinkList.Count*1.0/
Convert.ToInt64(reader["SampleRowCount"]);
var path = edge as MatchPath;
if (path != null)
{
if (path.AverageDegree > 1)
if (path.MaxLength != -1)
{
path.AverageDegree = Math.Pow(path.AverageDegree, path.MaxLength) -
(path.MinLength > 0
? Math.Pow(path.AverageDegree, path.MinLength - 1)
: 0);
}
else
path.AverageDegree = double.MaxValue;
}
}
}
// Retrieves density value for each node table
string tempTableName = Path.GetRandomFileName().Replace(".", "").Substring(0, 8);
var dbccDensityQuery = new StringBuilder();
dbccDensityQuery.Append(string.Format(@"CREATE TABLE #{0} (Density float, Len int, Col sql_variant);
INSERT INTO #{0} EXEC('", tempTableName));
Dictionary<Tuple<string, string>, List<MatchNode>> schemaTableToNodeListMapping =
new Dictionary<Tuple<string, string>, List<MatchNode>>();
foreach (var subGraph in graph.ConnectedSubGraphs)
{
foreach (var node in subGraph.Nodes.Values)
{
var tableTuple = WNamedTableReference.SchemaNameToTuple(node.NodeTableObjectName);
if (_graphMetaData.NodeViewMapping.ContainsKey(tableTuple))
{
node.GlobalNodeIdDensity = Statistics.DefaultDensity;
}
else
{
var nodeList = schemaTableToNodeListMapping.GetOrCreate(tableTuple);
nodeList.Add(node);
}
}
}
foreach (var tableTuple in schemaTableToNodeListMapping.Keys)
{
dbccDensityQuery.Append(string.Format(
"DBCC SHOW_STATISTICS (\"{0}.{1}\", [{0}{1}_PK_GlobalNodeId]) with DENSITY_VECTOR;\n",
tableTuple.Item1,
tableTuple.Item2));
}
dbccDensityQuery.Append("');\n");
dbccDensityQuery.Append(string.Format("SELECT Density FROM #{0} WHERE Col = 'GlobalNodeId'", tempTableName));
command.CommandText = dbccDensityQuery.ToString();
using (var reader = command.ExecuteReader())
{
foreach (var item in schemaTableToNodeListMapping)
{
double density;
if (!reader.Read())
density = Statistics.DefaultDensity;
else
{
density = Convert.ToDouble(reader["Density"]);
if (Math.Abs(density - 1.0) < 0.0001)
density = Statistics.DefaultDensity;
}
foreach (var node in item.Value)
{
node.GlobalNodeIdDensity = density;
}
}
}
}
}
/// <summary>
/// Item1: current node. A query will be sent to the server to fetch this node if this is the first time it appears in the whole list.
/// Item2: the traversalEdge whose sink is current node.
/// Item3: traversalEdges whose source is currentNode.
/// This list will either contain 0 or 1 traversal edge in the current version, and it will be pushed to server if possible.
/// Item4: backwardMatchingEdges.
/// Item5: forwardMatchingEdges.
/// </summary>
/// <param name="traversalChain"></param>
/// <returns></returns>
protected List <Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> > > GenerateTraversalOrderFromTraversalChain
(List <Tuple <MatchNode, MatchEdge, MatchNode, List <MatchEdge>, List <MatchEdge> > > traversalChain)
{
Dictionary <string, int> nodeFetchingOrderDict = new Dictionary <string, int>();
List <Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> > > optimizedTraversalOrder
= new List <Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> > >();
foreach (Tuple <MatchNode, MatchEdge, MatchNode, List <MatchEdge>, List <MatchEdge> > tuple in traversalChain)
{
MatchNode srcNode = tuple.Item1;
MatchEdge traversalEdge = tuple.Item2;
int nodeFetchingOrder;
if (nodeFetchingOrderDict.TryGetValue(srcNode.NodeAlias, out nodeFetchingOrder))
{
List <MatchEdge> traversalEdges = optimizedTraversalOrder[nodeFetchingOrder].Item3;
if (traversalEdges.Count == 0)
{
traversalEdges.Add(traversalEdge);
}
else
{
optimizedTraversalOrder.Add(
new Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> >(
srcNode,
null,
new List <MatchEdge> {
traversalEdge
},
new List <MatchEdge>(), new List <MatchEdge>()));
}
}
else
{
nodeFetchingOrderDict.Add(srcNode.NodeAlias, optimizedTraversalOrder.Count);
optimizedTraversalOrder.Add(
new Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> >(
srcNode,
null,
traversalEdge != null ? new List <MatchEdge> {
traversalEdge
} : new List <MatchEdge>(),
new List <MatchEdge>(), new List <MatchEdge>()));
}
if (traversalEdge != null)
{
MatchNode sinkNode = tuple.Item3;
List <MatchEdge> backwardEdges = tuple.Item4;
List <MatchEdge> forwardEdges = tuple.Item5;
nodeFetchingOrderDict.Add(sinkNode.NodeAlias, optimizedTraversalOrder.Count);
optimizedTraversalOrder.Add(
new Tuple <MatchNode, MatchEdge, List <MatchEdge>, List <MatchEdge>, List <MatchEdge> >(
sinkNode,
traversalEdge,
new List <MatchEdge>(),
backwardEdges, forwardEdges));
}
}
return(optimizedTraversalOrder);
}
/// <summary>
/// Span the table given the edge using cross apply
/// </summary>
/// <param name="tableRef"></param>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <param name="dumbNode"></param>
/// <returns></returns>
public WTableReference SpanTableRef(WTableReference tableRef, MatchEdge edge, string nodeAlias, string dumbNode, GraphMetaData metaData)
{
tableRef = new WUnqualifiedJoin
{
FirstTableRef = tableRef,
SecondTableRef = edge.ToSchemaObjectFunction(nodeAlias, dumbNode, metaData),
UnqualifiedJoinType = UnqualifiedJoinType.CrossApply,
};
return tableRef;
}
public ColumnStatistics GetEdgeStatistics(MatchEdge edge)
{
return(_edgeStatisticses[edge]);
}
public ColumnStatistics GetEdgeStatistics(MatchEdge edge)
{
return _edgeStatisticses[edge];
}
internal bool TryGetEdge(string alias, out MatchEdge edge)
{
return(this.GraphPattern.TryGetEdge(alias, out edge));
}
public void AddEdgeReference(MatchEdge edge)
{
var edgeAlias = edge.EdgeAlias;
if (_nodeTableDictionary.ContainsKey(edgeAlias) || _edgeDictionary.ContainsKey(edgeAlias))
throw new GraphViewException("Duplicate Alias");
_edgeDictionary.Add(edgeAlias,
new Tuple<WSchemaObjectName, WColumnReferenceExpression>(edge.SourceNode.NodeTableObjectName,
edge.EdgeColumn));
}
/// <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);
}
/// <summary>
/// Construct Graph from the match clause. The Graph can consist of multiple connected SubGraph.
/// Not supported in this version
/// </summary>
/// <param name="query"></param>
/// <returns></returns>
private MatchGraph ConstructGraph(WSelectQueryBlock query)
{
var unionFind = new UnionFind();
if (query.MatchClause == null)
return null;
var edgeTableReferenceDict = new Dictionary<string, List<string>>(StringComparer.CurrentCultureIgnoreCase);
var matchClause = query.MatchClause;
var nodes = new Dictionary<string, MatchNode>(StringComparer.CurrentCultureIgnoreCase);
var connectedSubGraphs = new List<ConnectedComponent>();
var subGrpahMap = new Dictionary<string, ConnectedComponent>(StringComparer.CurrentCultureIgnoreCase);
var parent = new Dictionary<string, string>(StringComparer.CurrentCultureIgnoreCase);
unionFind.Parent = parent;
HashSet<Tuple<string, string>> nodeTypes = new HashSet<Tuple<string, string>>();
//Construct Graph from Match Pattern
foreach (var path in matchClause.Paths)
{
var index = 0;
MatchEdge preEdge = null;
for (var count = path.PathNodeList.Count; index < count; ++index)
{
var currentNode = path.PathNodeList[index].Item1;
var currentEdge = path.PathNodeList[index].Item2;
var currentNodeExposedName = currentNode.BaseIdentifier.Value;
var nextNode = index != count - 1
? path.PathNodeList[index + 1].Item1
: path.Tail;
var nextNodeExposedName = nextNode.BaseIdentifier.Value;
var node = nodes.GetOrCreate(currentNodeExposedName);
if (node.NodeAlias == null)
{
node.NodeAlias = currentNodeExposedName;
node.Neighbors = new List<MatchEdge>();
node.External = false;
var nodeTable = _context[currentNodeExposedName] as WNamedTableReference;
if (nodeTable != null)
{
node.TableObjectName = nodeTable.TableObjectName;
if (node.TableObjectName.SchemaIdentifier == null)
node.TableObjectName.Identifiers.Insert(0, new Identifier { Value = "dbo" });
var nodeTypeTuple = WNamedTableReference.SchemaNameToTuple(node.TableObjectName);
if (!nodeTypes.Contains(nodeTypeTuple))
nodeTypes.Add(nodeTypeTuple);
}
}
if (currentEdge.AliasRole == AliasType.Default)
{
var currentEdgeName = currentEdge.MultiPartIdentifier.Identifiers.Last().Value;
if (edgeTableReferenceDict.ContainsKey(currentEdgeName))
{
edgeTableReferenceDict[currentEdgeName].Add(currentEdge.Alias);
}
else
{
edgeTableReferenceDict.Add(currentEdgeName, new List<string> { currentEdge.Alias });
}
}
var edge = new MatchEdge
{
SourceNode = node,
EdgeColumn = new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier
{
Identifiers = new List<Identifier>
{
new Identifier {Value = node.NodeAlias},
currentEdge.MultiPartIdentifier.Identifiers.Last()
}
}
},
EdgeAlias = currentEdge.Alias
};
if (preEdge != null)
{
preEdge.SinkNode = node;
}
preEdge = edge;
if (!parent.ContainsKey(currentNodeExposedName))
parent[currentNodeExposedName] = currentNodeExposedName;
if (!parent.ContainsKey(nextNodeExposedName))
parent[nextNodeExposedName] = nextNodeExposedName;
unionFind.Union(currentNodeExposedName, nextNodeExposedName);
node.Neighbors.Add(edge);
_context.AddEdgeReference(currentEdge.Alias, edge.SourceNode.TableObjectName, currentEdge);
}
var tailExposedName = path.Tail.BaseIdentifier.Value;
var tailNode = nodes.GetOrCreate(tailExposedName);
if (tailNode.NodeAlias == null)
{
tailNode.NodeAlias = tailExposedName;
tailNode.Neighbors = new List<MatchEdge>();
var nodeTable = _context[tailExposedName] as WNamedTableReference;
if (nodeTable != null)
{
tailNode.TableObjectName = nodeTable.TableObjectName;
if (tailNode.TableObjectName.SchemaIdentifier == null)
tailNode.TableObjectName.Identifiers.Insert(0, new Identifier { Value = "dbo" });
var nodeTypeTuple = WNamedTableReference.SchemaNameToTuple(tailNode.TableObjectName);
if (!nodeTypes.Contains(nodeTypeTuple))
nodeTypes.Add(nodeTypeTuple);
}
}
if (preEdge != null)
preEdge.SinkNode = tailNode;
}
// Put nodes into subgraphs
foreach (var node in nodes)
{
string root = unionFind.Find(node.Key);
if (!subGrpahMap.ContainsKey(root))
{
var subGraph = new ConnectedComponent();
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGrpahMap[root] = subGraph;
connectedSubGraphs.Add(subGraph);
subGraph.IsTailNode[node.Value] = false;
}
else
{
var subGraph = subGrpahMap[root];
subGraph.Nodes[node.Key] = node.Value;
foreach (var edge in node.Value.Neighbors)
{
subGraph.Edges[edge.EdgeAlias] = edge;
}
subGraph.IsTailNode[node.Value] = false;
}
}
// Replace Edge name alias with proper alias in the query
var replaceTableRefVisitor = new ReplaceTableRefVisitor();
replaceTableRefVisitor.Invoke(query, edgeTableReferenceDict);
// If a table alias in the MATCH clause is defined in an upper-level context,
// to be able to translate this MATCH clause, this table alias must be re-materialized
// in the FROM clause of the current context and joined with the corresponding table
// in the upper-level context.
var tableRefs = query.FromClause.TableReferences;
var tableSet = new HashSet<string>(StringComparer.CurrentCultureIgnoreCase);
var newTableRefs = new List<WTableReference>();
for (int index = 0; index < tableRefs.Count; ++index)
{
var table = tableRefs[index] as WNamedTableReference;
if (table == null)
{
newTableRefs.Add(tableRefs[index]);
continue;
}
var tableTuple = WNamedTableReference.SchemaNameToTuple(table.TableObjectName);
if (!nodeTypes.Contains(tableTuple))
{
newTableRefs.Add(table);
}
else
{
tableSet.Add(table.ExposedName.Value);
}
}
query.FromClause = new WFromClause
{
TableReferences = newTableRefs,
};
WBooleanExpression whereCondiction = null;
foreach (var node in nodes)
{
if (!tableSet.Contains(node.Key))
{
node.Value.External = true;
var newWhereCondition = new WBooleanComparisonExpression
{
ComparisonType = BooleanComparisonType.Equals,
FirstExpr = new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier { Value = node.Key },
new Identifier { Value = "GlobalNodeId" })
},
SecondExpr = new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier(
new Identifier { Value = node.Value.RefAlias },
new Identifier { Value = "GlobalNodeId" })
},
};
whereCondiction = WBooleanBinaryExpression.Conjunction(whereCondiction, newWhereCondition);
}
}
if (whereCondiction != null)
{
if (query.WhereClause == null)
{
query.WhereClause = new WWhereClause { SearchCondition = whereCondiction };
}
else
{
if (query.WhereClause.SearchCondition == null)
{
query.WhereClause.SearchCondition = whereCondiction;
}
else
{
query.WhereClause.SearchCondition = new WBooleanBinaryExpression
{
BooleanExpressionType = BooleanBinaryExpressionType.And,
FirstExpr = new WBooleanParenthesisExpression
{
Expression = query.WhereClause.SearchCondition
},
SecondExpr = new WBooleanParenthesisExpression
{
Expression = whereCondiction
}
};
}
}
}
var graph = new MatchGraph
{
ConnectedSubGraphs = connectedSubGraphs,
NodeTypesSet = nodeTypes,
};
unionFind.Parent = null;
return graph;
}
private void UpdateComponent(MatchComponent curComponent, CandidateJoinUnit candidateTree)
{
Dictionary <string, MatchNode> nodes = curComponent.Nodes;
Dictionary <MatchEdge, bool> edgeMaterializedDict = curComponent.EdgeMaterilizedDict;
Dictionary <MatchNode, List <MatchEdge> > unmaterializedNodeMapping = curComponent.UnmaterializedNodeMapping;
MatchNode root = candidateTree.TreeRoot;
if (!nodes.ContainsKey(root.NodeAlias))
{
nodes.Add(root.NodeAlias, new MatchNode(root));
}
curComponent.MaterializedNodeSplitCount[root] = 0;
List <Tuple <MaterializedOrder, MatchEdge> > inEdges =
candidateTree.PreMatIncomingEdges.Select(
e => new Tuple <MaterializedOrder, MatchEdge>(MaterializedOrder.Pre, e))
.Union(
candidateTree.PostMatIncomingEdges.Select(
e => new Tuple <MaterializedOrder, MatchEdge>(MaterializedOrder.Post, e)))
.ToList();
List <Tuple <MaterializedOrder, MatchEdge> > outEdges =
candidateTree.PreMatOutgoingEdges.Select(
e => new Tuple <MaterializedOrder, MatchEdge>(MaterializedOrder.Pre, e))
.Union(
candidateTree.PostMatOutgoingEdges.Select(
e => new Tuple <MaterializedOrder, MatchEdge>(MaterializedOrder.Post, e)))
.ToList();
if (inEdges.Any())
{
unmaterializedNodeMapping.Remove(root);
foreach (Tuple <MaterializedOrder, MatchEdge> t in inEdges)
{
MaterializedOrder order = t.Item1;
MatchEdge edge = t.Item2;
edgeMaterializedDict[edge] = true;
List <string> adjListProperties = this.PopulateAdjacencyListProperties(edge);
MatchNode node = curComponent.Nodes[edge.SourceNode.NodeAlias];
foreach (string adjListProperty in adjListProperties)
{
node.Properties.Add(adjListProperty);
}
}
}
if (outEdges.Any())
{
foreach (Tuple <MaterializedOrder, MatchEdge> t in outEdges)
{
MaterializedOrder order = t.Item1;
MatchEdge edge = t.Item2;
edgeMaterializedDict[edge] = true;
List <string> adjListProperties = this.PopulateAdjacencyListProperties(edge);
MatchNode node = curComponent.Nodes[edge.SourceNode.NodeAlias];
foreach (string adjListProperty in adjListProperties)
{
node.Properties.Add(adjListProperty);
}
}
}
List <MatchEdge> unmatEdges = candidateTree.UnmaterializedEdges;
foreach (MatchEdge unmatEdge in unmatEdges)
{
edgeMaterializedDict[unmatEdge] = false;;
List <MatchEdge> unmatNodeInEdges = unmaterializedNodeMapping.GetOrCreate(unmatEdge.SinkNode);
unmatNodeInEdges.Add(unmatEdge);
}
}
/// <summary>
/// Updates the statistics histogram for the edge given the sink id list.
/// Bucket size is pre-defined
/// </summary>
/// <param name="edge"></param>
/// <param name="sinkList">sink id of the edge sampling</param>
internal static void UpdateEdgeHistogram(MatchEdge edge, List <long> sinkList)
{
sinkList.Sort();
var rowCount = sinkList.Count;
var statistics = new Statistics
{
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);
}
// Generates 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);
}
edge.Statistics = statistics;
}
/// <summary>
/// Generate the Table-Valued Function by the edge given the node alias
/// </summary>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <returns></returns>
private static WTableReference EdgeToTableReference(MatchEdge edge, string nodeAlias)
{
var edgeColumn = edge.EdgeColumn;
var edgeIdentifiers = edge.EdgeColumn.MultiPartIdentifier.Identifiers;
if (nodeAlias != edgeIdentifiers.First().Value)
{
var identifiers = new List<Identifier>(edgeIdentifiers);
identifiers.RemoveAt(0);
identifiers.Insert(0, new Identifier
{
Value = nodeAlias
});
edgeColumn = new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier
{
Identifiers = identifiers
}
};
}
var columnName = edgeIdentifiers.Last().Value;
var deColIdentifiers = new Identifier[]
{
edgeColumn.MultiPartIdentifier.Identifiers.First(),
new Identifier {Value = columnName + "DeleteCol"}
};
var decoderFunction = new Identifier
{
Value = edge.SourceNode.TableObjectName.SchemaIdentifier.Value + '_' +
edge.SourceNode.TableObjectName.BaseIdentifier.Value + '_' +
columnName + '_' +
"Decoder",
};
var tableRef = new WSchemaObjectFunctionTableReference
{
SchemaObject = new WSchemaObjectName(
new Identifier {Value = "dbo"},
decoderFunction),
Parameters = new List<WScalarExpression>
{
edgeColumn,
new WColumnReferenceExpression
{
MultiPartIdentifier = new WMultiPartIdentifier(deColIdentifiers)
}
},
Alias = new Identifier
{
Value = edge.EdgeAlias,
}
};
return tableRef;
}
public void AddEdgeStatistics(MatchEdge edge, ColumnStatistics statistics)
{
_edgeStatisticses.Add(edge, statistics);
}
/// <summary>
/// Span the table given the edge using cross apply
/// </summary>
/// <param name="tableRef"></param>
/// <param name="edge"></param>
/// <param name="nodeAlias"></param>
/// <returns></returns>
public static WTableReference SpanTableRef(WTableReference tableRef, MatchEdge edge, string nodeAlias)
{
tableRef = new WUnqualifiedJoin
{
FirstTableRef = tableRef,
SecondTableRef = EdgeToTableReference(edge, nodeAlias),
UnqualifiedJoinType = UnqualifiedJoinType.CrossApply,
};
return tableRef;
}
public bool TryGetEdge(string key, out MatchEdge edge)
{
foreach (var subGraph in ConnectedSubGraphs)
{
if (subGraph.Edges.TryGetValue(key, out edge))
{
return true;
}
}
edge = null;
return false;
}
// Greate the MatchGraph of this AggregationBlock. If some free nodes and free edges are connected, they are in the same ConnectedComponent
internal HashSet <string> CreateMatchGraph(WMatchClause matchClause)
{
HashSet <string> freeNodesAndEdges = new HashSet <string>();
Dictionary <string, MatchPath> pathCollection = new Dictionary <string, MatchPath>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, MatchNode> nodeCollection = new Dictionary <string, MatchNode>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, MatchEdge> edgeCollection = new Dictionary <string, MatchEdge>(StringComparer.OrdinalIgnoreCase);
Dictionary <string, ConnectedComponent> subgraphCollection = new Dictionary <string, ConnectedComponent>(StringComparer.OrdinalIgnoreCase);
// we use Disjoint-set data structure to determine whether tables are in the same component or not.
UnionFind unionFind = new UnionFind();
foreach (ConnectedComponent subgraph in this.GraphPattern.ConnectedSubgraphs)
{
foreach (KeyValuePair <string, MatchNode> pair in subgraph.Nodes)
{
nodeCollection.Add(pair.Key, pair.Value);
unionFind.Add(pair.Key);
}
}
if (matchClause != null)
{
foreach (WMatchPath path in matchClause.Paths)
{
int index = 0;
bool outOfBlock = false;
MatchEdge edgeToSrcNode = null;
for (int count = path.PathEdgeList.Count; index < count; ++index)
{
WSchemaObjectName currentNodeTableRef = path.PathEdgeList[index].Item1;
WEdgeColumnReferenceExpression currentEdgeColumnRef = path.PathEdgeList[index].Item2;
WSchemaObjectName nextNodeTableRef = index != count - 1
? path.PathEdgeList[index + 1].Item1
: path.Tail;
string currentNodeExposedName = currentNodeTableRef.BaseIdentifier.Value;
string edgeAlias = currentEdgeColumnRef.Alias;
string nextNodeExposedName = nextNodeTableRef != null ? nextNodeTableRef.BaseIdentifier.Value : null;
// Get the source node of a path
if (!nodeCollection.ContainsKey(currentNodeExposedName))
{
continue;
}
MatchNode srcNode = nodeCollection[currentNodeExposedName];
// Get the edge of a path, and set required attributes
// Because the sourceNode is relative, we need to construct new edges or paths
// But they need to share the same predicates and proerties
MatchEdge edgeFromSrcNode;
if (currentEdgeColumnRef.MinLength == 1 && currentEdgeColumnRef.MaxLength == 1)
{
if (!edgeCollection.ContainsKey(edgeAlias))
{
edgeCollection[edgeAlias] = new MatchEdge()
{
LinkAlias = edgeAlias,
SourceNode = srcNode,
EdgeType = currentEdgeColumnRef.EdgeType,
Predicates = new List <WBooleanExpression>(),
BindNodeTableObjName = new WSchemaObjectName(),
IsReversed = false,
Properties = new List <string>(GraphViewReservedProperties.ReservedEdgeProperties)
};
unionFind.Add(edgeAlias);
}
edgeFromSrcNode = new MatchEdge
{
LinkAlias = edgeAlias,
SourceNode = srcNode,
EdgeType = edgeCollection[edgeAlias].EdgeType,
Predicates = edgeCollection[edgeAlias].Predicates,
BindNodeTableObjName = edgeCollection[edgeAlias].BindNodeTableObjName,
IsReversed = false,
Properties = edgeCollection[edgeAlias].Properties
};
}
else
{
if (!pathCollection.ContainsKey(edgeAlias))
{
pathCollection[edgeAlias] = new MatchPath
{
SourceNode = srcNode,
LinkAlias = edgeAlias,
Predicates = new List <WBooleanExpression>(),
BindNodeTableObjName = new WSchemaObjectName(),
MinLength = currentEdgeColumnRef.MinLength,
MaxLength = currentEdgeColumnRef.MaxLength,
ReferencePathInfo = false,
AttributeValueDict = currentEdgeColumnRef.AttributeValueDict,
IsReversed = false,
EdgeType = currentEdgeColumnRef.EdgeType,
Properties = new List <string>(GraphViewReservedProperties.ReservedEdgeProperties)
};
}
edgeFromSrcNode = new MatchPath
{
SourceNode = srcNode,
LinkAlias = edgeAlias,
Predicates = pathCollection[edgeAlias].Predicates,
BindNodeTableObjName = pathCollection[edgeAlias].BindNodeTableObjName,
MinLength = pathCollection[edgeAlias].MinLength,
MaxLength = pathCollection[edgeAlias].MaxLength,
ReferencePathInfo = false,
AttributeValueDict = pathCollection[edgeAlias].AttributeValueDict,
IsReversed = false,
EdgeType = pathCollection[edgeAlias].EdgeType,
Properties = pathCollection[edgeAlias].Properties
};
}
if (path.IsReversed)
{
unionFind.Union(edgeAlias, currentNodeExposedName);
}
else
{
unionFind.Union(currentNodeExposedName, edgeAlias);
}
if (edgeToSrcNode != null)
{
edgeToSrcNode.SinkNode = srcNode;
if (!(edgeToSrcNode is MatchPath))
{
// Construct reverse edge
MatchEdge reverseEdge = new MatchEdge
{
SourceNode = edgeToSrcNode.SinkNode,
SinkNode = edgeToSrcNode.SourceNode,
LinkAlias = edgeToSrcNode.LinkAlias,
Predicates = edgeToSrcNode.Predicates,
BindNodeTableObjName = edgeToSrcNode.BindNodeTableObjName,
IsReversed = true,
EdgeType = edgeToSrcNode.EdgeType,
Properties = edgeToSrcNode.Properties,
};
srcNode.ReverseNeighbors.Add(reverseEdge);
}
}
edgeToSrcNode = edgeFromSrcNode;
// Add this edge to node's neightbors
if (nextNodeExposedName != null)
{
if (path.IsReversed)
{
unionFind.Union(nextNodeExposedName, edgeAlias);
}
else
{
unionFind.Union(edgeAlias, nextNodeExposedName);
}
srcNode.Neighbors.Add(edgeFromSrcNode);
}
// Add this edge to node's dangling edges
else
{
srcNode.DanglingEdges.Add(edgeFromSrcNode);
}
}
if (path.Tail == null)
{
continue;
}
// Get destination node of a path
string tailExposedName = path.Tail.BaseIdentifier.Value;
if (!nodeCollection.ContainsKey(tailExposedName))
{
continue;
}
MatchNode destNode = nodeCollection[tailExposedName];
if (edgeToSrcNode != null)
{
edgeToSrcNode.SinkNode = destNode;
if (!(edgeToSrcNode is MatchPath))
{
// Construct reverse edge
MatchEdge reverseEdge = new MatchEdge
{
SourceNode = edgeToSrcNode.SinkNode,
SinkNode = edgeToSrcNode.SourceNode,
LinkAlias = edgeToSrcNode.LinkAlias,
Predicates = edgeToSrcNode.Predicates,
BindNodeTableObjName = edgeToSrcNode.BindNodeTableObjName,
IsReversed = true,
EdgeType = edgeToSrcNode.EdgeType,
Properties = edgeToSrcNode.Properties,
};
destNode.ReverseNeighbors.Add(reverseEdge);
}
}
}
}
// Use union find algorithmn to define which subgraph does a node belong to and put it into where it belongs to.
foreach (var node in nodeCollection)
{
freeNodesAndEdges.Add(node.Key);
string root = unionFind.Find(node.Key);
ConnectedComponent subGraph;
if (!subgraphCollection.ContainsKey(root))
{
subGraph = new ConnectedComponent();
subgraphCollection[root] = subGraph;
}
else
{
subGraph = subgraphCollection[root];
}
subGraph.Nodes[node.Key] = node.Value;
subGraph.IsTailNode[node.Value] = false;
foreach (MatchEdge edge in node.Value.Neighbors)
{
subGraph.Edges[edge.LinkAlias] = edge;
freeNodesAndEdges.Add(edge.LinkAlias);
}
foreach (MatchEdge edge in node.Value.DanglingEdges)
{
subGraph.Edges[edge.LinkAlias] = edge;
edge.IsDanglingEdge = true;
freeNodesAndEdges.Add(edge.LinkAlias);
}
if (node.Value.Neighbors.Count + node.Value.ReverseNeighbors.Count + node.Value.DanglingEdges.Count > 0)
{
node.Value.Properties.Add(GremlinKeyword.Star);
}
}
this.GraphPattern = new MatchGraph(subgraphCollection.Values.ToList());
return(freeNodesAndEdges);
}
public void AddEdgeStatistics(MatchEdge edge, ColumnStatistics statistics)
{
_edgeStatisticses.Add(edge, statistics);
}