Queryable Linq query hangs indefinitely when trying to execute it via a WebApi application

[mariana-gendler]

I am trying to execute the following query using the Influx.Client.Linq "Queryable" API:

var converter = new NumericSeriesEntryConverter(seriesId, tenant, storage);
var memberResolver = new NumericSeriesEntryMemberResolver();
var queryAPI = influxClient.GetQueryApi(converter);

 var query = from s in InfluxDBQueryable<NumericSeriesEntry>.Queryable(bucket, org, queryAPI, memberResolver)
                where s.SeriesId == seriesId
                select s;

The following line hangs indefinitely without any errors:
List<NumericSeriesEntry> results = query.ToList();

Executing the same logic via a .NET application works as expected, meaning that I am able to retrieve the results successfully

According the call stack, the logic hangs in the following method:

InfluxDB.Client.Linq.dll!InfluxDB.Client.Linq.Internal.InfluxDBQueryExecutor.ExecuteCollection<InfluxDBPOCWebApi.Entities.NumericSeriesEntry>
[External Code]
InfluxDBPOCWebApi.dll!InfluxDBPOCWebApi.Controllers.NumericSeriesEntryController.Get() Line 38
[External Code]

[bednar]

Hi @mariana-gendler,

thanks for feedback.

I am not able to simulate the hangs 😞. I've try it with this testing app: https://github.com/influxdata/influxdb-client-csharp/tree/feat/linq-prototype/Examples.WebApi and everything works correctly.

But I also improved a InfluxDBQueryExecutor.ExecuteCollection to bring better solution for transform Async response from QueryApi to a synchronous LINQ results.

Could you please test your code with new version?

dotnet add package InfluxDB.Client.Linq --version 1.15.0-dev.linq.7

Could you also share a little bit more how your WebApi stack looks like?

Regards

[mtstowe81]

Hi @bednar,

@mariana-gendler provided a sample application that reproduces the issue for us. please reference attached file. I will ask her to re-test with your fix as well.

Thanks
InfluxDBPOCWebApi.zip

[mariana-gendler]

Hi @bednar ,
Unfortunately, the issue still reproduces with the latest version of the code.
Please refer to the attached sample application that reproduces the issue and let me know if you have any questions

[mariana-gendler]

@bednar ,
Also wanted to mention that your samples contain a .NET core WebAPI application where as our existing legacy service is built on top of .NET standard WebAPI application so there might be some difference in that perspective

[bednar]

@mtstowe81, @mariana-gendler

thanks for detail information. I just tried your InfluxDBPOCWebApi with Visual Studio for Mac and everything works:

Which platform do you use? How do you start your WebApp?

[mariana-gendler]

@bednar ,
We run it directly from Visual studio in debug mode. The operation system is Windows 10. We have tried so far on two different developer machines and both have the same issue.
I will try to reproduce it on a Virtual machine in Microsoft Azure to try to confirm that it's not related to any corporate machine issues.
In the meantime, if you could try to execute this application on a Windows machine and see if the issue reproduces it would be very helpful.

[bednar]

@mariana-gendler how much data do you have in InfluxDB? Maybe there is too much data…

Could you try limit the amount of data by something like: Take(10) or where s.Timestamp > new DateTime(2021, 01, 20, 8, 20, 15, DateTimeKind.Utc)?

[mariana-gendler]

@bednar ,
I have only one record for the seriesId that I'm using and I can successfully retrieve it while executing this code from a .NET application but not the WebAPI application.
In addition to this being reproducible on two developer machines, I managed to reproduce it on a Virtual Machine I just deployed on the Azure cloud.
This virtual machine is running Windows 10 and only has Visual Studio 2017 installed.

Please see the attached screenshot with the line of code and the call stack

[bednar]

I am able to reproduce it too - Win 10 + Latest Visual Studio. I will try to figure out where is problem and fix it as soon as possible.

[bednar]

@mariana-gendler the issue is fixed in a latest preview version of library:

dotnet add package InfluxDB.Client.Linq --version 1.15.0-dev.linq.8

The problem was in transforming asynchronous response from InfluxDB into synchronous result in LINQ provider. I had to add a synchronous version of query into our QueryApi and use it in LINQ provider:

• influxdb-client-csharp/Client/QueryApi.cs

  Line 290 in 22f6f2b

  public List<T> QuerySync<T>(Query query, string org)

• influxdb-client-csharp/Client.Linq/Internal/QueryExecutor.cs

  Line 65 in 5a199bd

  return _queryApi.QuerySync<T>(query, _org);

[mariana-gendler]

@bednar ,
I can confirm that the issue is resolved in the latest version you provided.
Thanks a lot for the quick response!

[deanasheehan]

Thanks @bednar