protected override BoundRelation RewriteJoinRelation(BoundJoinRelation node)
{
node = (BoundJoinRelation)base.RewriteJoinRelation(node);
var needsRewriting = NeedsRewriting(node);
if (!needsRewriting)
{
return(node);
}
var node1 = (BoundJoinRelation)Instatiator.Instantiate(node);
var node2 = (BoundJoinRelation)Instatiator.Instantiate(node);
var leftOuterJoin = node1.Update(BoundJoinType.LeftOuter, node1.Left, node1.Right, node1.Condition, null, null);
var leftAntiSemiJoin = node1.Update(BoundJoinType.LeftAntiSemi, node2.Right, node2.Left, node2.Condition, null, null);
var computedValueSlots = node.Left.GetOutputValues().Select(v => v.Duplicate()).ToImmutableArray();
var computedValues = computedValueSlots.Select(v => new BoundComputedValue(Expression.Null(), v));
var compute = new BoundComputeRelation(leftAntiSemiJoin, computedValues);
var project = new BoundProjectRelation(compute, computedValueSlots.Concat(leftAntiSemiJoin.GetOutputValues()));
var concatValueSlots = node.GetOutputValues().ToImmutableArray();
var firstOutputs = leftOuterJoin.GetOutputValues().ToImmutableArray();
var secondOutputs = project.GetOutputValues().ToImmutableArray();
var unifiedValues = new BoundUnifiedValue[concatValueSlots.Length];
for (var i = 0; i < unifiedValues.Length; i++)
{
unifiedValues[i] = new BoundUnifiedValue(concatValueSlots[i], new[] { firstOutputs[i], secondOutputs[i] });
}
return(new BoundConcatenationRelation(new BoundRelation[] { leftOuterJoin, project }, unifiedValues));
}
private BoundRelation InstantiateCommonTableExpression(ImmutableArray <ValueSlot> outputValues, CommonTableExpressionSymbol symbol)
{
var prototype = symbol.Anchor.Relation;
var prototypeOutputValues = prototype.GetOutputValues();
var mapping = outputValues.Zip(prototypeOutputValues, (v, k) => new KeyValuePair <ValueSlot, ValueSlot>(k, v));
var instantiatedRelation = Instatiator.Instantiate(prototype, mapping);
return(RewriteRelation(instantiatedRelation));
}
private BoundRelation InstantiateRecursiveCommonTableExpression(ImmutableArray <ValueSlot> outputValues, CommonTableExpressionSymbol symbol)
{
// TableSpoolPusher
// Concat
// Compute (Recursion := 0)
// <Anchor>
// Assert (Recursion <= 100)
// Inner Join
// Compute (Recursion := Recursion + 1)
// TableSpoolPopper
// Concat
// Filter <RecursiveJoinPredicate1>
// <RecursiveMember1>
// Filter <RecursiveJoinPredicate2>
// <RecursiveMember2>
var valueSlotFactory = outputValues.First().Factory;
// Create output values
var unionRecusionSlot = valueSlotFactory.CreateTemporary(typeof(int));
var concatValueSlots = outputValues.Add(unionRecusionSlot);
// Create anchor
var anchor = RewriteRelation(Instatiator.Instantiate(symbol.Anchor.Relation));
var anchorValues = anchor.GetOutputValues().ToImmutableArray();
var initRecursionSlot = valueSlotFactory.CreateTemporary(typeof(int));
var initRecursionDefinition = new BoundComputedValue(Expression.Literal(0), initRecursionSlot);
var initRecursion = new BoundComputeRelation(anchor, ImmutableArray.Create(initRecursionDefinition));
var initRecursionOutputs = anchorValues.Add(initRecursionSlot);
// Create TableSpoolPopper
var tableSpoolPopperSlots = initRecursionOutputs.Select(v => v.Duplicate()).ToImmutableArray();
var tableSpoolPopper = new BoundTableSpoolPopper(tableSpoolPopperSlots);
var anchorRecursionCounter = tableSpoolPopperSlots.Last();
var inc = Expression.Plus(Expression.Value(anchorRecursionCounter), Expression.Literal(1));
var incRecursionSlot = valueSlotFactory.CreateTemporary(typeof(int));
var incRecursionDefinition = new BoundComputedValue(inc, incRecursionSlot);
var incRecursion = new BoundComputeRelation(tableSpoolPopper, ImmutableArray.Create(incRecursionDefinition));
// Create recursive members
var recursiveRewriter = new CommonTableExpressionInstantiator(symbol);
var recursiveMembers = new List <BoundRelation>(symbol.RecursiveMembers.Length);
var recursiveMemberOutputs = new List <ImmutableArray <ValueSlot> >(symbol.RecursiveMembers.Length);
var anchorReferences = tableSpoolPopperSlots.RemoveAt(tableSpoolPopperSlots.Length - 1);
foreach (var recursiveMember in symbol.RecursiveMembers)
{
var recursivePrototype = recursiveMember.Relation;
var mapping = CreateRecursiveMemberInstanceValueSlotMapping(symbol, anchorReferences, recursivePrototype);
var recursiveInstance = Instatiator.Instantiate(recursivePrototype, mapping);
var recursiveRelation = recursiveRewriter.RewriteRelation(recursiveInstance);
var recursiveRelationOutputs = recursiveRelation.GetOutputValues().ToImmutableArray();
recursiveMembers.Add(recursiveRelation);
recursiveMemberOutputs.Add(recursiveRelationOutputs);
}
// Concatenate recursive members
var recursiveConcatValues = Enumerable
.Range(0, concatValueSlots.Length - 1)
.Select(i =>
{
var slot = valueSlotFactory.CreateTemporary(concatValueSlots[i].Type);
return(new BoundUnifiedValue(slot, recursiveMemberOutputs.Select(o => o[i])));
})
.ToImmutableArray();
var hasSingleRecursiveMember = recursiveMembers.Count == 1;
var recursiveConcat = hasSingleRecursiveMember ? recursiveMembers.Single() : new BoundConcatenationRelation(recursiveMembers, recursiveConcatValues);
var recursionOutputs = hasSingleRecursiveMember ? recursiveMemberOutputs.Single() : recursiveConcatValues.Select(u => u.ValueSlot).ToImmutableArray();
// Create inner join
var join = new BoundJoinRelation(BoundJoinType.Inner, incRecursion, recursiveConcat, null, null, null);
var joinOutputs = recursionOutputs.Add(incRecursionSlot);
var recursiveProjection = new BoundProjectRelation(join, joinOutputs);
// Create assert
var assertCondition = Expression.LessThan(Expression.Value(incRecursionSlot), Expression.Literal(100));
var assert = new BoundAssertRelation(recursiveProjection, assertCondition, Resources.MaximumRecursionLevelExceeded);
// Create top level concat
var concatValues = concatValueSlots.Select((v, i) =>
{
var slots = new[]
{
initRecursionOutputs[i],
joinOutputs[i]
};
return(new BoundUnifiedValue(v, slots));
});
var concatInputs = new BoundRelation[] { initRecursion, assert };
var concat = new BoundConcatenationRelation(concatInputs, concatValues);
var tableSpoolPusher = new BoundTableSpoolPusher(concat);
return(new BoundProjectRelation(tableSpoolPusher, concatValueSlots.Take(concatValueSlots.Length - 1)));
}