System.Threading.Tasks.TaskCanceledException: A task was canceled

[Matthias De Ridder]

We have a baseline server which we use to execute tests on our development code. These tests are executed every day. The create a new database, import a lot of data after which the tests are executed.

Since last week, we receive a lot of these exceptions during our data import:

[System.Threading.Tasks.TaskCanceledException]

System.Threading.Tasks.TaskCanceledException: A task was canceled.

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

   at Raven.Client.Extensions.TaskExtensions2.ResultUnwrap[T](Task`1 task) in c:\Builds\RavenDB-Stable-3.0\Raven.Client.Lightweight\Extensions\TaskExtensions2.cs:line 59

   at Raven.Client.Connection.ServerClient.Batch(IEnumerable`1 commandDatas) in c:\Builds\RavenDB-Stable-3.0\Raven.Client.Lightweight\Connection\ServerClient.cs:line 295

   at Raven.Client.Document.DocumentSession.SaveChanges() in c:\Builds\RavenDB-Stable-3.0\Raven.Client.Lightweight\Document\DocumentSession.cs:line 715

We are using the 3684 unstable version. When we are receiving this error, we are trying to save batches of 128 documents to the database. We googled if there was already a solution for this error, but we only found this mention so far.

Is this a known issue? What is causing this exception? Is there a way to solve this?

[Maxim Buryak]

Hi,

Could you share your logs?

see http://ravendb.net/docs/article-page/2.5/csharp/server/deployment/docs-debug-logging

Best Regards,

Hibernating Rhinos Ltd  

Maxim Buryak l Core Team Developer l Mobile:+972-54-217-7751

Office: +972-4-622-7811 l Fax: +972-153-4-622-7811

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[Matthias De Ridder]

Yes, of course. I will post them as soon as possible.

I want to add we installed the latest unstable and encountered the same exception.

Op maandag 27 juli 2015 10:23:01 UTC+2 schreef Maxim Buryak:

[Oren Eini (Ayende Rahien)]

This is usually an indication of a timeout.

Are you updating a document that is being referenced by a lot of LoadDocument?

Hibernating Rhinos Ltd  

Oren Eini l CEO l Mobile: + 972-52-548-6969

[Matthias De Ridder]

We are creating a new database. In the steps where the exception occurs, the documents are inserted for the first time.

Op maandag 27 juli 2015 10:52:19 UTC+2 schreef Oren Eini:

[Oren Eini (Ayende Rahien)]

Can it be this issue?

http://ayende.com/blog/171169/production-postmortem-the-case-of-the-intransigent-new-database

[Matthias De Ridder]

I don't think so. We receive the exception after the database is created and is already populated with 1,000,000+ documents. The exception always occurs in the same step, but at random intervals. 

I have run the I/O test and these are our result. I'm currently importing the data again with the NLog configuration activated.

[Oren Eini (Ayende Rahien)]

Can you pipe this through Fiddler?

Hibernating Rhinos Ltd  

Oren Eini l CEO l Mobile: + 972-52-548-6969

Office: +972-4-622-7811 l Fax: +972-153-4-622-7811

 

[Matthias De Ridder]

I assume you mean our baseline test? I'll look to set it up.

What exactly are you looking for from Fiddler?

[Oren Eini (Ayende Rahien)]

To see what the responses are over the wire

[Matthias De Ridder]

This is the log and capture from when the error occurred. From what I can see, the log does not show a lot of information. In the capture file, request id 5720 and up are the ones that went wrong.

​

 Capture.saz

​

[Oren Eini (Ayende Rahien)]

You are saving 12 - 14 MB in each request, and they complete in about 30 seconds each.

That is what is causing the timeout exception. Try using a smaller batch size, 32, for example. Or using bulk insert.

Hibernating Rhinos Ltd  

Oren Eini l CEO l Mobile: + 972-52-548-6969

Office: +972-4-622-7811 l Fax: +972-153-4-622-7811

 

[Matthias De Ridder]

Thank you. We will give it a try.

Op maandag 27 juli 2015 14:22:47 UTC+2 schreef Oren Eini:

[Kamran Ayub]

On this note Oren, is it possible for Raven to write this info to Trace? Request size and duration... would help with debugging these issues on a non-local machine.

[Oren Eini (Ayende Rahien)]

See: 

http://ayende.com/blog/167713/ravendb-3-0-ops-live-tracing-logging-for-production

http://ayende.com/blog/168516/what-is-new-in-ravendb-3-0-operations-production-view

You can get those from RavenDB directly.

Hibernating Rhinos Ltd  

Oren Eini l CEO l Mobile: + 972-52-548-6969

Office: +972-4-622-7811 l Fax: +972-153-4-622-7811

 

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[Kamran Ayub]

Awesome, thank you.

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