private DryadQueryNode VisitPartitionOp(string opName,
QueryNodeInfo source,
QueryNodeType nodeType,
Expression controlExpr,
MethodCallExpression queryExpr)
{
DryadQueryNode resNode;
if (nodeType == QueryNodeType.TakeWhile &&
controlExpr.Type.GetGenericArguments().Length != 2)
{
// The "indexed" version.
resNode = this.Visit(source);
// The following block used to be skipped for resNode.OutputPartition.Count == 1,
// which causes compilation error (bug 13593)
// @@TODO[p3] : implement a working optimization for nPartition==1 that calls
// directly to Linq TakeWhile.
// Note: the test is: if (resNode.IsDynamic || resNode.OutputPartition.Count > 1)
{
resNode.IsForked = true;
bool isLong = (queryExpr.Method.Name == "LongTakeWhile");
DryadQueryNode offsetNode = this.CreateOffset(isLong, queryExpr, resNode);
// Create (x, y) => GroupIndexedTakeWhile(x, y, controlExpr)
Type ptype1 = typeof(IEnumerable<>).MakeGenericType(resNode.OutputTypes[0]);
Type ptype2 = typeof(IEnumerable<>).MakeGenericType(typeof(IndexedValue<long>));
ParameterExpression param1 = Expression.Parameter(ptype1, HpcLinqCodeGen.MakeUniqueName("x"));
ParameterExpression param2 = Expression.Parameter(ptype2, HpcLinqCodeGen.MakeUniqueName("y"));
string methodName = "GroupIndexed" + queryExpr.Method.Name;
MethodInfo minfo = typeof(HpcLinqEnumerable).GetMethod(methodName);
minfo = minfo.MakeGenericMethod(resNode.OutputTypes[0]);
Expression body = Expression.Call(minfo, param1, param2, controlExpr);
Type type = typeof(Func<,,>).MakeGenericType(ptype1, ptype2, body.Type);
LambdaExpression procFunc = Expression.Lambda(type, body, param1, param2);
resNode = new DryadApplyNode(procFunc, queryExpr, resNode, offsetNode);
}
}
else if (!source.IsForked &&
(nodeType == QueryNodeType.Take || nodeType == QueryNodeType.TakeWhile) &&
(source.OperatorName == "OrderBy" || source.OperatorName == "OrderByDescending"))
{
resNode = this.Visit(source.children[0].child);
bool isDescending = (source.OperatorName == "OrderByDescending");
MethodCallExpression sourceQueryExpr = (MethodCallExpression)source.queryExpression;
LambdaExpression keySelectExpr = HpcLinqExpression.GetLambda(sourceQueryExpr.Arguments[1]);
Expression comparerExpr = null;
if (sourceQueryExpr.Arguments.Count == 3)
{
comparerExpr = sourceQueryExpr.Arguments[2];
}
resNode = this.PromoteConcat(
source.children[0].child,
resNode,
delegate(DryadQueryNode x) {
DryadQueryNode y = new DryadOrderByNode(keySelectExpr, comparerExpr,
isDescending, sourceQueryExpr, x);
return FirstStagePartitionOp(opName, nodeType, controlExpr, queryExpr, y);
});
if (resNode.IsDynamic || resNode.OutputPartition.Count > 1)
{
// Need a mergesort
resNode = new DryadMergeNode(keySelectExpr, comparerExpr, isDescending, false, sourceQueryExpr, resNode);
}
}
else
{
resNode = this.Visit(source);
if (nodeType == QueryNodeType.Take || nodeType == QueryNodeType.TakeWhile)
{
resNode = this.PromoteConcat(
source, resNode,
x => FirstStagePartitionOp(opName, nodeType, controlExpr, queryExpr, x));
}
}
resNode = new DryadPartitionOpNode(opName, nodeType, controlExpr, false, queryExpr, resNode);
return resNode;
}
internal virtual string Visit(DryadPartitionOpNode node,
CodeMemberMethod vertexMethod,
string[] readerNames,
string[] writerNames)
{
return node.AddVertexCode(vertexMethod, readerNames, writerNames);
}