private static CardinalityEstimate EstimateStreamAggregatesRelation(BoundStreamAggregatesRelation relation)
{
if (!relation.Groups.Any())
{
return(CardinalityEstimate.SingleRow);
}
return(CardinalityEstimate.Unknown);
}
protected override BoundRelation RewriteStreamAggregatesRelation(BoundStreamAggregatesRelation node)
{
var aggregates = RemoveUnusedSlots(node.Aggregates, a => a.Output);
node = node.Update(node.Input, node.Groups, aggregates);
_recorder.Record(node.Aggregates);
_recorder.Record(node.Groups);
return(base.RewriteStreamAggregatesRelation(node));
}
private Iterator BuildStreamAggregatesRelation(BoundStreamAggregatesRelation relation)
{
var input = BuildRelation(relation.Input);
var allocation = BuildRowBufferAllocation(relation.Input, input.RowBuffer);
var aggregators = relation.Aggregates
.Select(a => a.Aggregatable.CreateAggregator())
.ToImmutableArray();
var argumentFunctions = relation.Aggregates
.Select(a => BuildFunction(a.Argument, allocation))
.ToImmutableArray();
var groupEntries = relation.Groups
.Select(g => allocation[g.ValueSlot])
.ToImmutableArray();
var comparers = relation.Groups.Select(v => v.Comparer).ToImmutableArray();
return(new StreamAggregateIterator(input, groupEntries, comparers, aggregators, argumentFunctions));
}
