fix: remove download overhead for Queries (#181)

Author: bednar

CHANGELOG.md

@@ -12,6 +12,7 @@
 ### Bug Fixes
 1. [#168](https://github.com/influxdata/influxdb-client-csharp/pull/168): DateTime is always serialized into UTC
 1. [#169](https://github.com/influxdata/influxdb-client-csharp/pull/169): Fixed domain structure for Flux AST
+1. [#181](https://github.com/influxdata/influxdb-client-csharp/pull/181): Removed download overhead for Queries
 
 ### Dependencies
 1. [#175](https://github.com/influxdata/influxdb-client-csharp/pull/175): Updated dependencies of `InfluxDB.Client`:

Client.Core/Internal/AbstractQueryClient.cs

@@ -113,7 +113,12 @@ private async Task Query(RestRequest query, Action<ICancellable, Stream> consume
                     consumer(cancellable, responseStream);
                 };
 
-                await Task.Run(() => { RestClient.DownloadData(query, true); }).ConfigureAwait(false);
+                var restResponse = await RestClient.ExecuteAsync(query, Method.POST).ConfigureAwait(false);
+                if (restResponse.ErrorException != null)
+                {
+                    throw restResponse.ErrorException;
+                }
+                
                 if (!cancellable.IsCancelled())
                 {
                     onComplete();
@@ -147,7 +152,12 @@ private void QuerySync(RestRequest query, Action<ICancellable, Stream> consumer,
                     consumer(cancellable, responseStream);
                 };
 
-                RestClient.DownloadData(query, true);
+                var restResponse = RestClient.Execute(query, Method.POST);
+                if (restResponse.ErrorException != null)
+                {
+                    throw restResponse.ErrorException;
+                }
+                
                 if (!cancellable.IsCancelled())
                 {
                     onComplete();

Client.Legacy/FluxClient.cs

@@ -423,7 +423,7 @@ private async Task<IRestResponse> ExecuteAsync(RestRequest request)
         {
             BeforeIntercept(request);
 
-            var response = await Task.Run(() => RestClient.Execute(request)).ConfigureAwait(false);
+            var response = await RestClient.ExecuteAsync(request).ConfigureAwait(false);
 
             RaiseForInfluxError(response, response.Content);
 

Client.Test/QueryApiTest.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using InfluxDB.Client.Core;
+using InfluxDB.Client.Core.Flux.Domain;
+using InfluxDB.Client.Core.Test;
+using NUnit.Framework;
+using WireMock.RequestBuilders;
+
+namespace InfluxDB.Client.Test
+{
+    [TestFixture]
+    public class QueryApiTest : AbstractMockServerTest
+    {
+        private InfluxDBClient _influxDbClient;
+        private QueryApi _queryApi;
+
+        private const string Data =
+            "#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,dateTime:RFC3339,string,string,string,string,double\n"
+            + "#group,false,false,false,false,false,false,false,false,false,false\n"
+            + "#default,_result,,,,,,,,,\n"
+            + ",result,table,_start,_stop,_time,id,_field,_measurement,host,_value\n"
+            + ",,0,1970-01-01T00:00:10Z,1970-01-01T00:00:20Z,1970-01-01T00:00:10Z,ab,free,mem,A,12.25\n"
+            + ",,0,1970-01-01T00:00:10Z,1970-01-01T00:00:20Z,1970-01-01T00:00:10Z,cd,free,mem,A,13.00\n";
+
+        [SetUp]
+        public new void SetUp()
+        {
+            var options = InfluxDBClientOptions.Builder
+                .CreateNew()
+                .Url(MockServerUrl)
+                .AuthenticateToken("token")
+                .Org("my-org")
+                .Build();
+            
+            _influxDbClient = InfluxDBClientFactory.Create(options);
+            _influxDbClient.SetLogLevel(LogLevel.Body);
+            _queryApi = _influxDbClient.GetQueryApi();
+        }
+
+        [Test]
+        public async Task ParallelRequest()
+        {
+            MockServer
+                .Given(Request.Create().WithPath("/api/v2/query").UsingPost())
+                .RespondWith(CreateResponse(Data));
+
+            var stopWatch = new Stopwatch();
+            stopWatch.Start();
+            
+            var tasks = new List<Task<List<FluxTable>>>();
+            foreach (var _ in Enumerable.Range(0, 100))
+            {
+                tasks.Add(_queryApi.QueryAsync("from(bucket:\"my-bucket\") |> range(start: 0)", "my-org"));
+            }
+            await Task.WhenAll(tasks);
+            
+            var ts = stopWatch.Elapsed;
+            Assert.LessOrEqual(ts.TotalSeconds, 10, $"Elapsed time: {ts}");
+        }
+    }
+}