private Iterator BuildAssert(BoundAssertRelation relation)
{
var input = BuildRelation(relation.Input);
var allocation = BuildRowBufferAllocation(relation.Input, input.RowBuffer);
var predicate = BuildPredicate(relation.Condition, true, allocation);
return(new AssertIterator(input, predicate, relation.Message));
}
protected override BoundExpression RewriteSingleRowSubselect(BoundSingleRowSubselect node)
{
var relation = RewriteRelation(node.Relation);
var factory = node.Value.Factory;
// TODO: If the query is guranteed to return a single, e.g. if it is a aggregated but not grouped,
// we should not emit the additional aggregation and assertion.
// 1. We need to know whether it returns more then one row.
var valueSlot = node.Value;
var anyOutput = factory.CreateTemporary(valueSlot.Type);
var countOutput = factory.CreateTemporary(typeof(int));
var anyAggregateSymbol = BuiltInAggregates.Any;
var anyAggregatable = anyAggregateSymbol.Definition.CreateAggregatable(valueSlot.Type);
var countAggregatedSymbol = BuiltInAggregates.Count;
var countAggregatable = countAggregatedSymbol.Definition.CreateAggregatable(typeof(int));
var aggregates = new[]
{
new BoundAggregatedValue(anyOutput, anyAggregateSymbol, anyAggregatable, Expression.Value(valueSlot)),
new BoundAggregatedValue(countOutput, countAggregatedSymbol, countAggregatable, Expression.Literal(0))
};
var aggregation = new BoundGroupByAndAggregationRelation(relation, Enumerable.Empty <BoundComparedValue>(), aggregates);
// 2. Now we can assert that the number of rows returned is at most one.
var condition = Expression.LessThan(Expression.Value(countOutput), Expression.Literal(1));
var message = Resources.SubqueryReturnedMoreThanRow;
var assertRelation = new BoundAssertRelation(aggregation, condition, message);
var subquery = new Subquery(SubqueryKind.Subselect, anyOutput, assertRelation, CurrentPassthru);
var subqueries = _subqueryStack.Peek();
subqueries.Add(subquery);
return(Expression.Value(anyOutput));
}
private static CardinalityEstimate EstimateAssertRelation(BoundAssertRelation relation)
{
// TODO: If we knew more about the asser (such as MAX(1) or MAX(100)) we'd be able to give better estimates.
return(Estimate(relation.Input));
}
protected override BoundRelation RewriteAssertRelation(BoundAssertRelation node)
{
_recorder.Record(node.Condition);
return(base.RewriteAssertRelation(node));
}
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)));
}
