private static void CostDecreaseForLeavingInlinedIndependent(SearchPlanEdge planEdge)
{
// considerably lower the costs for operations leaving the inlined independent part, so this is done early
if (planEdge.Target is SearchPlanEdgeNode) // we may leave the independent part only with an edge
{
if (planEdge.Source.PatternElement.OriginalIndependentElement != null) // when the start is a node from an inlined independent
{
SearchPlanEdgeNode edge = (SearchPlanEdgeNode)planEdge.Target;
if (edge.PatternEdgeSource.PatternElement.OriginalIndependentElement != null && edge.PatternEdgeTarget.PatternElement.OriginalIndependentElement == null ||
edge.PatternEdgeSource.PatternElement.OriginalIndependentElement == null && edge.PatternEdgeTarget.PatternElement.OriginalIndependentElement != null)
{ // and the edge is incident to elements inside and outside of the inlined independent
planEdge.Cost = (float)Math.Sqrt(Math.Sqrt(planEdge.Cost));
}
}
}
}
/// <summary>
/// Generates a scheduled search plan for a given search plan graph
/// </summary>
public static ScheduledSearchPlan ScheduleSearchPlan(SearchPlanGraph spGraph,
PatternGraph patternGraph, bool isNegativeOrIndependent, bool lazyNegativeIndependentConditionEvaluation)
{
// the schedule
List <SearchOperation> operations = new List <SearchOperation>();
// a set of search plan edges representing the currently reachable not yet visited elements
PriorityQueue <SearchPlanEdge> activeEdges = new PriorityQueue <SearchPlanEdge>();
// first schedule all preset elements
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Target.IsPreset && edge.Type != SearchOperationType.DefToBeYieldedTo)
{
foreach (SearchPlanEdge edgeOutgoingFromPresetElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPresetElement);
}
// note: here a normal preset is converted into a neg/idpt preset operation if in negative/independent pattern
SearchOperation newOp = new SearchOperation(
isNegativeOrIndependent ? SearchOperationType.NegIdptPreset : edge.Type,
edge.Target, spGraph.Root, 0);
operations.Add(newOp);
}
}
// then schedule all map with storage / pick from index / pick from storage / pick from name index elements not depending on other elements
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.MapWithStorage)
{
foreach (SearchPlanEdge edgeOutgoingFromPickedElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPickedElement);
}
SearchOperation newOp = new SearchOperation(edge.Type,
edge.Target, spGraph.Root, 0);
newOp.Storage = edge.Target.PatternElement.Storage;
newOp.StorageIndex = edge.Target.PatternElement.StorageIndex;
operations.Add(newOp);
}
}
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.PickFromStorage)
{
foreach (SearchPlanEdge edgeOutgoingFromPickedElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPickedElement);
}
SearchOperation newOp = new SearchOperation(edge.Type,
edge.Target, spGraph.Root, 0);
newOp.Storage = edge.Target.PatternElement.Storage;
operations.Add(newOp);
}
}
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.PickFromIndex)
{
foreach (SearchPlanEdge edgeOutgoingFromPickedElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPickedElement);
}
SearchOperation newOp = new SearchOperation(edge.Type,
edge.Target, spGraph.Root, 0);
newOp.IndexAccess = edge.Target.PatternElement.IndexAccess;
operations.Add(newOp);
}
}
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.PickByName)
{
foreach (SearchPlanEdge edgeOutgoingFromPickedElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPickedElement);
}
SearchOperation newOp = new SearchOperation(edge.Type,
edge.Target, spGraph.Root, 0);
newOp.NameLookup = edge.Target.PatternElement.NameLookup;
operations.Add(newOp);
}
}
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.PickByUnique)
{
foreach (SearchPlanEdge edgeOutgoingFromPickedElement in edge.Target.OutgoingEdges)
{
activeEdges.Add(edgeOutgoingFromPickedElement);
}
SearchOperation newOp = new SearchOperation(edge.Type,
edge.Target, spGraph.Root, 0);
newOp.UniqueLookup = edge.Target.PatternElement.UniqueLookup;
operations.Add(newOp);
}
}
// iterate over all reachable elements until the whole graph has been scheduled(/visited),
// choose next cheapest operation, update the reachable elements and the search plan costs
SearchPlanNode lastNode = spGraph.Root;
for (int i = 0; i < spGraph.Nodes.Length - spGraph.NumPresetElements - spGraph.NumIndependentStorageIndexElements; ++i)
{
foreach (SearchPlanEdge edge in lastNode.OutgoingEdges)
{
if (edge.Target.IsPreset)
{
continue;
}
if (edge.Target.PatternElement.Storage != null &&
edge.Target.PatternElement.GetPatternElementThisElementDependsOnOutsideOfGraphConnectedness() == null)
{
continue;
}
if (edge.Target.PatternElement.IndexAccess != null &&
edge.Target.PatternElement.GetPatternElementThisElementDependsOnOutsideOfGraphConnectedness() == null)
{
continue;
}
if (edge.Target.PatternElement.NameLookup != null &&
edge.Target.PatternElement.GetPatternElementThisElementDependsOnOutsideOfGraphConnectedness() == null)
{
continue;
}
if (edge.Target.PatternElement.UniqueLookup != null &&
edge.Target.PatternElement.GetPatternElementThisElementDependsOnOutsideOfGraphConnectedness() == null)
{
continue;
}
CostDecreaseForLeavingInlinedIndependent(edge);
activeEdges.Add(edge);
}
SearchPlanEdge minEdge = activeEdges.DequeueFirst();
lastNode = minEdge.Target;
SearchOperation newOp = new SearchOperation(minEdge.Type,
lastNode, minEdge.Source, minEdge.Cost);
newOp.Storage = minEdge.Target.PatternElement.Storage;
newOp.StorageIndex = minEdge.Target.PatternElement.StorageIndex;
newOp.IndexAccess = minEdge.Target.PatternElement.IndexAccess;
newOp.NameLookup = minEdge.Target.PatternElement.NameLookup;
newOp.UniqueLookup = minEdge.Target.PatternElement.UniqueLookup;
foreach (SearchOperation op in operations)
{
op.CostToEnd += minEdge.Cost;
}
operations.Add(newOp);
}
// remove the elements stemming from inlined independents
// they were added in the hope that they might help in matching this pattern,
// they don't if they are matched after the elements of this pattern (in fact they only increase the costs then)
RemoveInlinedIndependentElementsAtEnd(operations);
// insert inlined element identity check into the schedule in case neither of the possible assignments was scheduled
InsertInlinedElementIdentityCheckIntoSchedule(patternGraph, operations);
// insert inlined variable assignments into the schedule
InsertInlinedVariableAssignmentsIntoSchedule(patternGraph, operations);
// insert conditions into the schedule
InsertConditionsIntoSchedule(patternGraph.ConditionsPlusInlined, operations, lazyNegativeIndependentConditionEvaluation);
// schedule the initialization of all def to be yielded to elements and variables at the end,
// must come after the pattern elements (and preset elements), as they may be used in the def initialization
foreach (SearchPlanEdge edge in spGraph.Root.OutgoingEdges)
{
if (edge.Type == SearchOperationType.DefToBeYieldedTo &&
(!isNegativeOrIndependent || (edge.Target.PatternElement.pointOfDefinition == patternGraph && edge.Target.PatternElement.originalElement == null)))
{
SearchOperation newOp = new SearchOperation(
SearchOperationType.DefToBeYieldedTo,
edge.Target, spGraph.Root, 0);
newOp.Expression = edge.Target.PatternElement.Initialization;
operations.Add(newOp);
}
}
foreach (PatternVariable var in patternGraph.variablesPlusInlined)
{
if (var.defToBeYieldedTo &&
(!isNegativeOrIndependent || var.pointOfDefinition == patternGraph && var.originalVariable == null))
{
SearchOperation newOp = new SearchOperation(
SearchOperationType.DefToBeYieldedTo,
var, spGraph.Root, 0);
newOp.Expression = var.initialization;
operations.Add(newOp);
}
}
float cost = operations.Count > 0 ? operations[0].CostToEnd : 0;
return(new ScheduledSearchPlan(patternGraph, operations.ToArray(), cost));
}
/// <summary>
/// Generate search plan graph out of the plan graph,
/// search plan graph only contains edges chosen by the MSA algorithm.
/// Edges in search plan graph are given in the nodes by outgoing list, as needed for scheduling,
/// in contrast to incoming list in plan graph, as needed for MSA computation.
/// </summary>
/// <param name="planGraph">The source plan graph</param>
/// <returns>A new search plan graph</returns>
public static SearchPlanGraph GenerateSearchPlanGraph(PlanGraph planGraph)
{
SearchPlanNode searchPlanRoot = new SearchPlanNode("search plan root");
SearchPlanNode[] searchPlanNodes = new SearchPlanNode[planGraph.Nodes.Length];
SearchPlanEdge[] searchPlanEdges = new SearchPlanEdge[planGraph.Nodes.Length - 1 + 1]; // +1 for root
Dictionary <PlanNode, SearchPlanNode> planToSearchPlanNode = // for generating edges
new Dictionary <PlanNode, SearchPlanNode>(planGraph.Nodes.Length);
planToSearchPlanNode.Add(planGraph.Root, searchPlanRoot);
// generate the search plan graph nodes, same as plan graph nodes,
// representing pattern graph nodes and edges
int i = 0;
foreach (PlanNode planNode in planGraph.Nodes)
{
if (planNode.NodeType == PlanNodeType.Edge)
{
searchPlanNodes[i] = new SearchPlanEdgeNode(planNode, null, null);
}
else
{
searchPlanNodes[i] = new SearchPlanNodeNode(planNode);
}
planToSearchPlanNode.Add(planNode, searchPlanNodes[i]);
++i;
}
// generate the search plan graph edges,
// that are the plan graph edges chosen by the MSA algorithm, in reversed direction
// and add references to originating pattern elements
i = 0;
foreach (PlanNode planNode in planGraph.Nodes)
{
PlanEdge planEdge = planNode.IncomingMSAEdge;
searchPlanEdges[i] = new SearchPlanEdge(planEdge.Type, planToSearchPlanNode[planEdge.Source], planToSearchPlanNode[planEdge.Target], planEdge.Cost);
planToSearchPlanNode[planEdge.Source].OutgoingEdges.Add(searchPlanEdges[i]);
if (planNode.NodeType == PlanNodeType.Edge)
{
SearchPlanEdgeNode searchPlanEdgeNode = (SearchPlanEdgeNode)planToSearchPlanNode[planNode];
SearchPlanNode patElem;
if (planEdge.Target.PatternEdgeSource != null &&
planToSearchPlanNode.TryGetValue(planEdge.Target.PatternEdgeSource, out patElem))
{
searchPlanEdgeNode.PatternEdgeSource = (SearchPlanNodeNode)patElem;
searchPlanEdgeNode.PatternEdgeSource.OutgoingPatternEdges.Add(searchPlanEdgeNode);
}
if (planEdge.Target.PatternEdgeTarget != null &&
planToSearchPlanNode.TryGetValue(planEdge.Target.PatternEdgeTarget, out patElem))
{
searchPlanEdgeNode.PatternEdgeTarget = (SearchPlanNodeNode)patElem;
searchPlanEdgeNode.PatternEdgeTarget.IncomingPatternEdges.Add(searchPlanEdgeNode);
}
}
++i;
}
return(new SearchPlanGraph(searchPlanRoot, searchPlanNodes, searchPlanEdges));
}
