public static bool DependsOnAny(this BoundExpression condition, IEnumerable <ValueSlot> valueSlots)
{
var finder = new ValueSlotDependencyFinder();
finder.VisitExpression(condition);
return(finder.ValueSlots.Overlaps(valueSlots));
}
private bool ConjunctionHasOuterReference(HashSet <ValueSlot> definedValueSet, BoundExpression conjunction)
{
var valueSlotFinder = new ValueSlotDependencyFinder();
valueSlotFinder.VisitExpression(conjunction);
return(!valueSlotFinder.ValueSlots.All(definedValueSet.Contains));
}
private static void BuildGraph(List <BoundRelation> relations, List <BoundExpression> predicates, out ICollection <JoinNode> nodes, out ICollection <JoinEdge> edges)
{
var nodeByRelation = relations.Select(r => new JoinNode(r)).ToDictionary(n => n.Relation);
nodes = nodeByRelation.Values;
edges = new List <JoinEdge>();
var edgeByNodes = new Dictionary <ValueTuple <JoinNode, JoinNode>, JoinEdge>();
var relationByValueSlot = relations.SelectMany(r => r.GetDefinedValues(), ValueTuple.Create)
.ToDictionary(t => t.Item2, t => t.Item1);
var dependencyFinder = new ValueSlotDependencyFinder();
foreach (var predicate in predicates)
{
dependencyFinder.ValueSlots.Clear();
dependencyFinder.VisitExpression(predicate);
var referencedSlots = dependencyFinder.ValueSlots;
var referencedRelations = referencedSlots.Where(v => relationByValueSlot.ContainsKey(v))
.Select(v => relationByValueSlot[v])
.ToImmutableArray();
if (referencedRelations.Length == 2)
{
var left = nodeByRelation[referencedRelations[0]];
var right = nodeByRelation[referencedRelations[1]];
var leftRight = ValueTuple.Create(left, right);
var rightLeft = ValueTuple.Create(right, left);
JoinEdge edge;
if (!edgeByNodes.TryGetValue(leftRight, out edge))
{
if (!edgeByNodes.TryGetValue(rightLeft, out edge))
{
edge = new JoinEdge(left, right);
left.Edges.Add(edge);
right.Edges.Add(edge);
edges.Add(edge);
edgeByNodes.Add(leftRight, edge);
}
}
edge.Conditions.Add(predicate);
}
}
}
protected override BoundRelation RewriteFilterRelation(BoundFilterRelation node)
{
// Check for null rejecting conditions.
var dependencyFinder = new ValueSlotDependencyFinder();
foreach (var conjunction in Expression.SplitConjunctions(node.Condition))
{
dependencyFinder.ValueSlots.Clear();
dependencyFinder.VisitExpression(conjunction);
var slots = dependencyFinder.ValueSlots;
var nullRejectedSlots = slots.Where(v => NullRejection.IsRejectingNull(conjunction, v));
foreach (var valueSlot in nullRejectedSlots)
{
AddNullRejectedTable(valueSlot);
}
}
return(base.RewriteFilterRelation(node));
}
protected override BoundRelation RewriteJoinRelation(BoundJoinRelation node)
{
// Get declared tables of left and right
var leftDefinedValues = node.Left.GetDefinedValues().ToImmutableArray();
var rightDefinedValues = node.Right.GetDefinedValues().ToImmutableArray();
// Replace outer joins by left-/right-/inner joins
if (node.JoinType == BoundJoinType.RightOuter ||
node.JoinType == BoundJoinType.FullOuter)
{
if (IsAnyNullRejected(leftDefinedValues))
{
var newType = node.JoinType == BoundJoinType.RightOuter
? BoundJoinType.Inner
: BoundJoinType.LeftOuter;
node = node.Update(newType, node.Left, node.Right, node.Condition, node.Probe, node.PassthruPredicate);
}
}
if (node.JoinType == BoundJoinType.LeftOuter ||
node.JoinType == BoundJoinType.FullOuter)
{
if (IsAnyNullRejected(rightDefinedValues))
{
var newType = node.JoinType == BoundJoinType.LeftOuter
? BoundJoinType.Inner
: BoundJoinType.RightOuter;
node = node.Update(newType, node.Left, node.Right, node.Condition, node.Probe, node.PassthruPredicate);
}
}
// After converting an outer join to an inner one we can
// sometimes eliminate the whole join.
if (node.JoinType == BoundJoinType.Inner)
{
if (node.Left is BoundConstantRelation && !node.Left.GetDefinedValues().Any())
{
return(RewriteRelation(WrapWithFilter(node.Right, node.Condition)));
}
if (node.Right is BoundConstantRelation && !node.Right.GetDefinedValues().Any())
{
return(RewriteRelation(WrapWithFilter(node.Left, node.Condition)));
}
}
// Analyze AND-parts of Condition
if (node.JoinType != BoundJoinType.FullOuter)
{
var dependencyFinder = new ValueSlotDependencyFinder();
foreach (var conjunction in Expression.SplitConjunctions(node.Condition))
{
// Check if we can derive from this conjunction that a table it depends on
// is null-rejected.
dependencyFinder.ValueSlots.Clear();
dependencyFinder.VisitExpression(conjunction);
var slots = dependencyFinder.ValueSlots;
var nullRejectedSlots = slots.Where(v => NullRejection.IsRejectingNull(conjunction, v));
foreach (var valueSlot in nullRejectedSlots)
{
if (node.JoinType != BoundJoinType.LeftOuter && leftDefinedValues.Contains(valueSlot))
{
AddNullRejectedTable(valueSlot);
}
else if (node.JoinType != BoundJoinType.RightOuter && rightDefinedValues.Contains(valueSlot))
{
AddNullRejectedTable(valueSlot);
}
}
}
}
// Visit children
return(base.RewriteJoinRelation(node));
}
public void Record(BoundExpression expression)
{
_finder.VisitExpression(expression);
}