private DLinqQueryNode VisitConcat(QueryNodeInfo source, MethodCallExpression queryExpr)
{
DLinqQueryNode[] childs = new DLinqQueryNode[source.Children.Count];
for (int i = 0; i < source.Children.Count; ++i)
{
childs[i] = this.Visit(source.Children[i].Child);
}
DLinqQueryNode resNode = new DLinqConcatNode(queryExpr, childs);
int parCount = resNode.OutputPartition.Count;
if (!resNode.IsDynamic && parCount > StaticConfig.MaxPartitionCount)
{
// Too many partitions, need to repartition
int newParCount = parCount / 2;
DLinqQueryNode countNode = new DLinqBasicAggregateNode(null, AggregateOpType.LongCount,
true, false, queryExpr, resNode);
DLinqQueryNode mergeCountNode = new DLinqMergeNode(true, queryExpr, countNode);
// Apply node for s => IndexedCount(s)
Type paramType = typeof(IEnumerable<>).MakeGenericType(typeof(long));
ParameterExpression param = Expression.Parameter(paramType, "s");
MethodInfo minfo = typeof(DryadLinqHelper).GetMethod("IndexedCount");
minfo = minfo.MakeGenericMethod(typeof(long));
Expression body = Expression.Call(minfo, param);
Type funcType = typeof(Func<,>).MakeGenericType(param.Type, body.Type);
LambdaExpression indexedCountFunc = Expression.Lambda(funcType, body, param);
DLinqQueryNode indexedCountNode = new DLinqApplyNode(indexedCountFunc, queryExpr, mergeCountNode);
// HashPartition(x => x.index, parCount)
param = Expression.Parameter(body.Type.GetGenericArguments()[0], "x");
Expression keySelectBody = Expression.Property(param, "Index");
funcType = typeof(Func<,>).MakeGenericType(param.Type, keySelectBody.Type);
LambdaExpression keySelectExpr = Expression.Lambda(funcType, keySelectBody, param);
DLinqQueryNode distCountNode = new DLinqHashPartitionNode(keySelectExpr,
null,
parCount,
queryExpr,
indexedCountNode);
// Apply node for (x, y) => AddPartitionIndex(x, y, newParCount)
ParameterExpression param1 = Expression.Parameter(body.Type, "x");
Type paramType2 = typeof(IEnumerable<>).MakeGenericType(resNode.OutputTypes[0]);
ParameterExpression param2 = Expression.Parameter(paramType2, "y");
minfo = typeof(DryadLinqHelper).GetMethod("AddPartitionIndex");
minfo = minfo.MakeGenericMethod(resNode.OutputTypes[0]);
body = Expression.Call(minfo, param1, param2, Expression.Constant(newParCount));
funcType = typeof(Func<,,>).MakeGenericType(param1.Type, param2.Type, body.Type);
LambdaExpression addIndexFunc = Expression.Lambda(funcType, body, param1, param2);
DLinqQueryNode addIndexNode = new DLinqApplyNode(addIndexFunc, queryExpr, distCountNode, resNode);
// HashPartition(x => x.index, x => x.value, newParCount)
param = Expression.Parameter(body.Type.GetGenericArguments()[0], "x");
body = Expression.Property(param, "Index");
funcType = typeof(Func<,>).MakeGenericType(param.Type, body.Type);
keySelectExpr = Expression.Lambda(funcType, body, param);
body = Expression.Property(param, "Value");
funcType = typeof(Func<,>).MakeGenericType(param.Type, body.Type);
LambdaExpression resultSelectExpr = Expression.Lambda(funcType, body, param);
resNode = new DLinqHashPartitionNode(keySelectExpr,
resultSelectExpr,
null,
newParCount,
false,
queryExpr,
addIndexNode);
resNode = new DLinqMergeNode(true, queryExpr, resNode);
}
return resNode;
}
internal virtual string Visit(DLinqConcatNode node,
CodeMemberMethod vertexMethod,
string[] readerNames,
string[] writerNames)
{
return node.AddVertexCode(vertexMethod, readerNames, writerNames);
}
private DLinqQueryNode PromoteConcat(QueryNodeInfo source,
DLinqQueryNode sourceNode,
Func<DLinqQueryNode, DLinqQueryNode> func)
{
DLinqQueryNode resNode = sourceNode;
if ((resNode is DLinqConcatNode) && !source.IsForked)
{
DLinqQueryNode[] children = resNode.Children;
DLinqQueryNode[] newChildren = new DLinqQueryNode[children.Length];
for (int i = 0; i < children.Length; i++)
{
children[i].Parents.Remove(resNode);
newChildren[i] = func(children[i]);
}
resNode = new DLinqConcatNode(source.QueryExpression, newChildren);
}
else
{
resNode = func(resNode);
}
return resNode;
}
