private DryadQueryNode VisitJoin(QueryNodeInfo outerSource,
QueryNodeInfo innerSource,
QueryNodeType nodeType,
LambdaExpression outerKeySelector,
LambdaExpression innerKeySelector,
LambdaExpression resultSelector,
Expression comparerExpr,
Expression queryExpr)
{
DryadQueryNode outerChild = this.Visit(outerSource);
DryadQueryNode innerChild = this.Visit(innerSource);
DryadQueryNode joinNode = null;
Type keyType = outerKeySelector.Type.GetGenericArguments()[1];
if (comparerExpr == null && !TypeSystem.HasDefaultEqualityComparer(keyType))
{
throw DryadLinqException.Create(HpcLinqErrorCode.ComparerMustBeSpecifiedOrKeyTypeMustBeIEquatable,
string.Format(SR.ComparerMustBeSpecifiedOrKeyTypeMustBeIEquatable, keyType),
queryExpr);
}
// The comparer object:
object comparer = null;
if (comparerExpr != null)
{
ExpressionSimplifier<object> evaluator = new ExpressionSimplifier<object>();
comparer = evaluator.Eval(comparerExpr);
}
if (outerChild.IsDynamic || innerChild.IsDynamic)
{
// Well, let us do the simplest thing for now
outerChild = new DryadHashPartitionNode(outerKeySelector,
comparerExpr,
StaticConfig.DefaultPartitionCount,
queryExpr,
outerChild);
if (IsMergeNodeNeeded(outerChild))
{
outerChild = new DryadMergeNode(false, false, queryExpr, outerChild);
}
innerChild = new DryadHashPartitionNode(innerKeySelector,
comparerExpr,
StaticConfig.DefaultPartitionCount,
queryExpr,
innerChild);
if (IsMergeNodeNeeded(innerChild))
{
innerChild = new DryadMergeNode(false, false, queryExpr, innerChild);
}
joinNode = new DryadJoinNode(nodeType,
"Hash" + nodeType,
outerKeySelector,
innerKeySelector,
resultSelector,
comparerExpr,
queryExpr,
outerChild,
innerChild);
return joinNode;
}
bool isOuterDescending = outerChild.OutputDataSetInfo.orderByInfo.IsDescending;
bool isInnerDescending = innerChild.OutputDataSetInfo.orderByInfo.IsDescending;
// Partition outer and inner if needed
if (outerChild.OutputPartition.ParType == PartitionType.Range &&
outerChild.OutputPartition.HasKeys &&
outerChild.OutputPartition.IsPartitionedBy(outerKeySelector, comparer))
{
if (innerChild.OutputPartition.ParType != PartitionType.Range ||
!innerChild.OutputPartition.IsPartitionedBy(innerKeySelector, comparer) ||
!outerChild.OutputPartition.IsSamePartition(innerChild.OutputPartition))
{
// Range distribute inner using outer's partition.
innerChild = outerChild.OutputPartition.CreatePartitionNode(innerKeySelector, innerChild);
if (IsMergeNodeNeeded(innerChild))
{
innerChild = new DryadMergeNode(false, false, queryExpr, innerChild);
}
}
}
else if (innerChild.OutputPartition.ParType == PartitionType.Range &&
innerChild.OutputPartition.HasKeys &&
innerChild.OutputPartition.IsPartitionedBy(innerKeySelector, comparer))
{
// Range distribute outer using inner's partition.
outerChild = innerChild.OutputPartition.CreatePartitionNode(outerKeySelector, outerChild);
if (IsMergeNodeNeeded(outerChild))
{
outerChild = new DryadMergeNode(false, false, queryExpr, outerChild);
}
}
else if (outerChild.OutputPartition.ParType == PartitionType.Hash &&
outerChild.OutputPartition.IsPartitionedBy(outerKeySelector, comparer))
{
if (innerChild.OutputPartition.ParType != PartitionType.Hash ||
!innerChild.OutputPartition.IsPartitionedBy(innerKeySelector, comparer) ||
!outerChild.OutputPartition.IsSamePartition(innerChild.OutputPartition))
{
innerChild = new DryadHashPartitionNode(innerKeySelector,
comparerExpr,
outerChild.OutputPartition.Count,
queryExpr,
innerChild);
if (IsMergeNodeNeeded(innerChild))
{
innerChild = new DryadMergeNode(false, false, queryExpr, innerChild);
}
}
}
else if (innerChild.OutputPartition.ParType == PartitionType.Hash &&
innerChild.OutputPartition.IsPartitionedBy(innerKeySelector, comparer))
{
outerChild = new DryadHashPartitionNode(outerKeySelector,
comparerExpr,
innerChild.OutputPartition.Count,
queryExpr,
outerChild);
if (IsMergeNodeNeeded(outerChild))
{
outerChild = new DryadMergeNode(false, false, queryExpr, outerChild);
}
}
else
{
// No luck. Hash partition both outer and inner
int parCnt = Math.Max(outerChild.OutputPartition.Count, innerChild.OutputPartition.Count);
if (parCnt > 1)
{
outerChild = new DryadHashPartitionNode(outerKeySelector,
comparerExpr,
parCnt,
queryExpr,
outerChild);
if (IsMergeNodeNeeded(outerChild))
{
outerChild = new DryadMergeNode(false, false, queryExpr, outerChild);
}
innerChild = new DryadHashPartitionNode(innerKeySelector,
comparerExpr,
parCnt,
queryExpr,
innerChild);
if (IsMergeNodeNeeded(innerChild))
{
innerChild = new DryadMergeNode(false, false, queryExpr, innerChild);
}
}
}
// Perform either merge or hash join
string opName = "Hash";
if (outerChild.IsOrderedBy(outerKeySelector, comparer))
{
if (!innerChild.IsOrderedBy(innerKeySelector, comparer) ||
isOuterDescending != isInnerDescending)
{
// Sort inner if unsorted
innerChild = new DryadOrderByNode(innerKeySelector, comparerExpr,
isOuterDescending, queryExpr, innerChild);
}
opName = "Merge";
}
else if (innerChild.IsOrderedBy(innerKeySelector, comparer))
{
if (!outerChild.IsOrderedBy(outerKeySelector, comparer) ||
isOuterDescending != isInnerDescending)
{
// Sort outer if unsorted
outerChild = new DryadOrderByNode(outerKeySelector, comparerExpr,
isInnerDescending, queryExpr, outerChild);
}
opName = "Merge";
}
joinNode = new DryadJoinNode(nodeType,
opName + nodeType,
outerKeySelector,
innerKeySelector,
resultSelector,
comparerExpr,
queryExpr,
outerChild,
innerChild);
return joinNode;
}
internal virtual string Visit(DryadJoinNode node,
CodeMemberMethod vertexMethod,
string[] readerNames,
string[] writerNames)
{
return node.AddVertexCode(vertexMethod, readerNames, writerNames);
}
