我正在使用Microsoft.AnalysisServices.adomdClient.dll文件连接到Azure Analysis Service，以便在Azure函数中执行DAX查询，我需要它在JSON中吐出。 下面是如何做的，但是当有大量的记录时，我看到在将响应转换为JSON时会出现延迟。 Analysis service在2秒内响应，但将响应屏蔽到json需要40秒以上的时间。 有人能提出一个更好的办法吗
AdomdCommand cmd = new AdomdCommand(query, _connect);
public List<Dictionary<string, object>> Results { get; } = new List<Dictionary<string, object>>();
var reader = cmd.ExecuteReader();
var schemeTable = reader.GetSchemaTable();
ISet<string> columnSet = new HashSet<string>();
foreach (DataRow row in schemeTable.Rows)
{
String columnName = row[0].ToString();
columnSet.Add(columnName);
}
while (reader.Read())
{
Dictionary<string, object> columns = new Dictionary<string, object>();
foreach (string columnName in columnSet)
{
var value = reader[reader.GetOrdinal(columnName)];
if (value != null)
{
columns.Add(columnName, value);
}
else
{
columns.Add(columnName, null);
}
}
Results.Add(columns);
}
JsonConvert.SerializeObject(Results)
我在GitHub上有一个示例:microsoft/azure-analysis-services-http-sample。 它将结果从AdomdDataReader以JSON的形式流到输出流。 流可以是MemoryStream或（在我的例子中）HttpResponse流。
public static async Task WriteResultsToStream(object results, Stream stream, CancellationToken cancel)
{
if (results == null)
{
return;
}
if (results is AdomdDataReader rdr)
{
var encoding = new System.Text.UTF8Encoding(false);
using (var tw = new StreamWriter(stream,encoding,1024*4,true))
using (var w = new Newtonsoft.Json.JsonTextWriter(tw))
{
await w.WriteStartObjectAsync(cancel);
var rn = "rows";
await w.WritePropertyNameAsync(rn);
await w.WriteStartArrayAsync(cancel);
while (rdr.Read())
{
await w.WriteStartObjectAsync(cancel);
for (int i = 0; i < rdr.FieldCount; i++)
{
string name = rdr.GetName(i);
object value = rdr.GetValue(i);
await w.WritePropertyNameAsync(name, cancel);
await w.WriteValueAsync(value, cancel);
}
await w.WriteEndObjectAsync(cancel);
}
await w.WriteEndArrayAsync(cancel);
await w.WriteEndObjectAsync(cancel);
await w.FlushAsync();
await tw.FlushAsync();
await stream.FlushAsync();
}
}
else if (results is CellSet cs)
{
throw new NotSupportedException("CellSet results");
}
else
{
throw new InvalidOperationException("Unexpected result type");
}
}
