111 lines
4.3 KiB
C#
111 lines
4.3 KiB
C#
using System;
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using System.Collections.Generic;
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using TDengineDriver;
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using TDengineDriver.Impl;
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using System.Runtime.InteropServices;
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namespace TDengineExample
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{
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public class AsyncQueryExample
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{
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static void Main()
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{
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IntPtr conn = GetConnection();
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try
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{
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QueryAsyncCallback queryAsyncCallback = new QueryAsyncCallback(QueryCallback);
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TDengine.QueryAsync(conn, "select * from meters", queryAsyncCallback, IntPtr.Zero);
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Thread.Sleep(2000);
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}
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finally
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{
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TDengine.Close(conn);
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}
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}
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static void QueryCallback(IntPtr param, IntPtr taosRes, int code)
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{
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if (code == 0 && taosRes != IntPtr.Zero)
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{
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FetchRawBlockAsyncCallback fetchRowAsyncCallback = new FetchRawBlockAsyncCallback(FetchRawBlockCallback);
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TDengine.FetchRawBlockAsync(taosRes, fetchRowAsyncCallback, param);
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}
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else
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{
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throw new Exception($"async query data failed,code:{code},reason:{TDengine.Error(taosRes)}");
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}
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}
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// Iteratively call this interface until "numOfRows" is no greater than 0.
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static void FetchRawBlockCallback(IntPtr param, IntPtr taosRes, int numOfRows)
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{
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if (numOfRows > 0)
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{
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Console.WriteLine($"{numOfRows} rows async retrieved");
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IntPtr pdata = TDengine.GetRawBlock(taosRes);
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List<TDengineMeta> metaList = TDengine.FetchFields(taosRes);
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List<object> dataList = LibTaos.ReadRawBlock(pdata, metaList, numOfRows);
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for (int i = 0; i < dataList.Count; i++)
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{
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if (i != 0 && (i + 1) % metaList.Count == 0)
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{
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Console.WriteLine("{0}\t|", dataList[i]);
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}
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else
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{
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Console.Write("{0}\t|", dataList[i]);
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}
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}
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Console.WriteLine("");
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TDengine.FetchRawBlockAsync(taosRes, FetchRawBlockCallback, param);
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}
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else
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{
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if (numOfRows == 0)
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{
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Console.WriteLine("async retrieve complete.");
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}
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else
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{
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throw new Exception($"FetchRawBlockCallback callback error, error code {numOfRows}");
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}
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TDengine.FreeResult(taosRes);
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}
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}
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static IntPtr GetConnection()
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{
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string host = "localhost";
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short port = 6030;
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string username = "root";
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string password = "taosdata";
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string dbname = "power";
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var conn = TDengine.Connect(host, username, password, dbname, port);
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if (conn == IntPtr.Zero)
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{
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throw new Exception("Connect to TDengine failed");
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}
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else
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{
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Console.WriteLine("Connect to TDengine success");
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}
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return conn;
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}
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}
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}
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// //output:
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// // Connect to TDengine success
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// // 8 rows async retrieved
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// // 1538548685500 | 11.8 | 221 | 0.28 | california.losangeles | 2 |
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// // 1538548696600 | 13.4 | 223 | 0.29 | california.losangeles | 2 |
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// // 1538548685000 | 10.8 | 223 | 0.29 | california.losangeles | 3 |
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// // 1538548686500 | 11.5 | 221 | 0.35 | california.losangeles | 3 |
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// // 1538548685000 | 10.3 | 219 | 0.31 | california.sanfrancisco | 2 |
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// // 1538548695000 | 12.6 | 218 | 0.33 | california.sanfrancisco | 2 |
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// // 1538548696800 | 12.3 | 221 | 0.31 | california.sanfrancisco | 2 |
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// // 1538548696650 | 10.3 | 218 | 0.25 | california.sanfrancisco | 3 |
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// // async retrieve complete. |