For some reason Azure SQL does not seem to be picking with my MultipleActiveResultSets=True in the connection string of my dotnet core app.
my apps connection string looks like this
Server=tcp:xxx.database.windows.net,1433;Initial Catalog=xxx;User ID=xxx;Password=xxxxx;MultipleActiveResultSets=True;Encrypt=True;"
I still keep getting this error
A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe.
All my code has awaits when using async methods so I have no idea what else to do because this code works with local sql.
I am using DI with my DbContext and adding the service like this
services.AddDbContext<Models.Database.DBContext>();
Any help would be greatly appreciated.
UPDATE
The problem was in my Startup.cs. I missed it. OnTokenValidated had a method which was calling dbcontext but i never awaited the result. Didn't see any errors from the IDE cause normally it will warn you about not awaiting an async method. Updated the method with an await and added OnTokenValidated = async context. All fine now.
This
A second operation started on this context before a previous operation
completed. Any instance members are not guaranteed to be thread safe.
Is an EF error, not a SQL Server error. So MultipleActiveResultSets is irrelevant.
All my code has awaits when using async methods . . .I am using DI with my DbContext
So probably your DI is allowing a DbContext instance to be shared between requests.
Related
I have a quarkus application with an async endpoint that creates an entity with default properties, starts a new thread within the request method and executes a long running job and then returns the entity as a response for the client to track.
#POST
#Transactional
public Response startJob(#NonNull JsonObject request) {
// create my entity
JobsRecord job = new JobsRecord();
// set default properties
job.setName(request.getString("name"));
// make persistent
jobsRepository.persist(job);
// start the long running job on a different thread
Executor.execute(() -> longRunning(job));
return Response.accepted().entity(job).build();
}
Additionally, the long running job will make updates to the entity as it runs and so it must also be transactional. However, the database entity just doesn't get updated.
These are the issues I am facing:
I get the following warnings:
ARJUNA012094: Commit of action id 0:ffffc0a80065:f2db:5ef4e1c7:0 invoked while multiple threads active within it.
ARJUNA012107: CheckedAction::check - atomic action 0:ffffc0a80065:f2db:5ef4e1c7:0 commiting with 2 threads active!
Seems like something that should be avoided.
I tried using #Transaction(value = TxType.REQUIRES_NEW) to no avail.
I tried using the API Approach instead of the #Transactional approach on longRunning as mentioned in the guide as follows:
#Inject UserTransaction transaction;
.
.
.
try {
transaction.begin();
jobsRecord.setStatus("Complete");
jobsRecord.setCompletedOn(new Timestamp(System.currentTimeMillis()));
transaction.commit();
} catch (Exception e) {
e.printStackTrace();
transaction.rollback();
}
but then I get the errors: ARJUNA016051: thread is already associated with a transaction! and ARJUNA016079: Transaction rollback status is:ActionStatus.COMMITTED
I tried both the declarative and API based methods again this time with context propagation enabled. But still no luck.
Finally, based on the third approach, I thought keeping the #Transactional on the Http request handler and leaving longRunning as is without declarative or API based transaction approaches would work. However the database still does not get updated.
Clearly I am misunderstanding how JTA and context propagation works (among other things).
Is there a way (or even a design pattern) that allows me to update database entities asynchronously in a quarkus web application? Also why wouldn't any of the approaches I took have any effect?
Using quarkus 1.4.1.Final with ext: [agroal, cdi, flyway, hibernate-orm, hibernate-orm-panache, hibernate-validator, kubernetes-client, mutiny, narayana-jta, rest-client, resteasy, resteasy-jackson, resteasy-mutiny, smallrye-context-propagation, smallrye-health, smallrye-openapi, swagger-ui]
You should return an async type from your JAX-RS resource method, the transaction context will then be available when the async stage executes. There is some relevant documentation in the quarkus guide on context propagation.
I would start by looking at the one of the reactive examples such as the getting started quickstart. Try annotating each resource endpoint with #Transactional and the async code will run with a transaction context.
I am having problems getting the Microsoft.Azure.Documents library to initialize the client in an azure worker role. I'm using Nuget Package 0.9.1-preview.
I have mimicked what was done in the example for azure document
When running locally through the emulator I can connect fine with the documentdb and it runs as expected. When running in the worker role, I am getting a series of NullReferenceException and then ArgumentNullException.
The bottom System.NullReferenceException that is highlighted above has this call stack
so the nullReferenceExceptions start in this call at the new DocumentClient.
var endpoint = "myendpoint";
var authKey = "myauthkey";
var enpointUri = new Uri(endpoint);
DocumentClient client = new DocumentClient(endpointUri, authKey);
Nothing changes between running it locally vs on the worker role other then the environment (obviously).
Has anyone gotten DocumentDb to work on a worker role or does anyone have an idea why it would be throwing null reference exceptions? The parameters getting passed into the DocumentClient() are filled.
UPDATE:
I tried to rewrite it being more generic which helped at least let the worker role run and let me attached a debugger. It is throwing the error on the new DocumentClient. Seems like some security passing is null. Both the required parameters on initialization are not null. Is there a security setting I need to change for my worker role to be able to connect to my documentdb? (still works locally fine)
UPDATE 2:
I can get the instance to run in release mode, but not debug mode. So it must be something to do with some security setting or storage setting that is misconfigured I guess?
It seems I'm getting System.Security.SecurityExceptions - only when using The DocumentDb - queues do not give me that error. All Call Stacks for that error seem to be with System.Diagnostics.EventLog. The very first Exception I see in the Intellitrace Summary is System.Threading.WaitHandleCannotBeOpenedException.
More Info
Intellitrace summary exception data:
top is the earliest and bottom is the latest (so System.Security.SecurityException happens first then the NullReference)
The solution for me to get rid of the security exception and null reference exception was to disable intellitrace. Once I did that, I was able to deploy and attach debugger and see everything working.
Not sure what is between the null in intellitrace and the DocumentClient, but hopefully it's just in relation to the nuget and it will be fixed in the next iteration.
unable to repro.
I created a new Worker Role. Single instance. Added authkey & endoint config to cscfg.
Created private static DocumentClient at WorkerRole class level
Init DocumentClient in OnStart
Dispose DocumentClient in OnStop
In RunAsync inside loop,
execute a query Works as expected.
Test in emulator works.
Deployed as Release to Production slot. works.
Deployed as Debug to Staging with Remote Debug. works.
Attached VS to CloudService, breakpoint hit inside loop.
Working solution : http://ryancrawcour.blob.core.windows.net/samples/AzureCloudService1.zip
I'm using MVC4 ApiController to upload data to Azure Blob. Here is the sample code:
public Task PostAsync(int id)
{
return Task.Factory.StartNew(() =>
{
// CloudBlob.UploadFromStream(stream);
});
}
Does this code even make sense? I think ASP.NET is already processing the request in a worker thread, so running UploadFromStream in another thread doesn't seem to make sense since it now uses two threads to run this method (I assume the original worker thread is waiting for this UploadFromStream to finish?)
So my understanding is that async ApiController only makes sense if we are using some built-in async methods such as HttpClient.GetAsync or SqlCommand.ExecuteReaderAsync. Those methods probably use I/O Completion Ports internally so it can free up the thread while doing the actual work. So I should change the code to this?
public Task PostAsync(int id)
{
// only to show it's using the proper async version of the method.
return TaskFactory.FromAsync(BeginUploadFromStream, EndUploadFromStream...)
}
On the other hand, if all the work in the Post method is CPU/memory intensive, then the async version PostAsync will not help throughput of requests. It might be better to just use the regular "public void Post(int id)" method, right?
I know it's a lot questions. Hopefully it will clarify my understanding of async usage in the ASP.NET MVC. Thanks.
Yes, most of what you say is correct. Even down to the details with completion ports and such.
Here is a tiny error:
I assume the original worker thread is waiting for this UploadFromStream to finish?
Only your task thread is running. You're using the async pipeline after all. It does not wait for the task to finish, it just hooks up a continuation. (Just like with HttpClient.GetAsync).
I have below application:
Its windows console .NET 3.0 application
I'm creating 20 workloads and assigning them to threadpool to process.
Each thread in ThreadPool creates WCF Client and calls service with request created using workload assigned.
Sometimes on production servers[12 core machines], I get following exception:
There was an error reflecting type 'xyz' while invoking operation using WCF client. This starts appearing in all threads. After sometime it suddenly disappears and starts appearing again.
Code:
Pseudo Code:
for(int i=0;i<20;i++)
{
MultiThreadedProcess proc =new MultThreadedProcess(someData[i]);
ThreadPool.QueueUserWorkItem(proc.CallBack,i);
}
In Class MultiThreadedProcess, I do something like this:
public void Callback(object index)
{
MyServiceClient client = new MyServiceClient();
MyServiceResponse response =client.SomeOperation(new MyServiceRequest(proc.SomeData));
client.close();
//Process Response
}
Can anyone suggest some resolutions for this problem?
If you can turn on diagnostic, appears to me serialization issue, there might be chance that certain data members/values are not able to de-serialized properly for operation call.
I have a .NET 4.5 WCF client app that uses the async/await pattern to make volumes of calls. My development machine is dual-proc with 8gb RAM (production will be 5 CPU with 8gb RAM at Amazon AWS) . The remote WCF service called by my code uses out and ref parameters on a web method that I need. My code instances a proxy client each time, writes any results to a public ConcurrentDictionary, and then returns null.
I ran Perfmon, watching the thread count on the system, and it goes between 28-30. It takes hours for my client to complete the volumes of calls that are made. Yes, hours. The remote service is backed by a big company, they have many servers to receive my WCF calls, so the more calls I can throw at them, the better.
I think that things are actually still happening synchronously, even though the method that makes the WCF call is decorated with "async" because the proxy method cannot have "await". Is that true?
My code looks like this:
async private void CallMe()
{
Console.WriteLine( DateTime.Now );
var workTasks = this.AnotherConcurrentDict.Select( oneB => GetData( etcetcetc ).Cast<Task>().ToList();
await Task.WhenAll( workTasks );
}
private async Task<WorkingBits> GetData(etcetcetc)
{
var commClient = new RemoteClient();
var cpResponse = new GetPackage();
var responseInfo = commClient.GetData( name, password , ref (cpResponse.aproperty), filterid , out cpResponse.Identifiers);
foreach (var onething in cpResponse.Identifiers)
{
// add to the ConcurrentDictionary
}
return null; // I already wrote to the ConcurrentDictionary so no need to return anything
responseInfo is not awaitable beacuse the WCF call has ref and out parameters.
I was thinking that way to speed this up is not to put async/await in this method, but instead create a wrapper method where I can make things await/async, but I am not that is the smartest/safest way to work it.
What is a smart way to get more outbound calls to the service (expand IO completion thread pool, trick calls into running in the background so Task.WhenAll can complete quicker)?
Thanks for all ideas/samples/pointers. I am hitting a bottleneck somewhere.
1) Make sure you're really calling it asynchronously, rather than just blocking on the calls. Code samples would help here.
2) You may need to do this:
ServicePointManager.DefaultConnectionLimit = 100;
By default it only allows 2 simultaneous connections to the same server.
3) Make sure you dispose the proxy object after the call is complete so you're not tying up resources.
If you're doing things asynchronously the threadpool size shouldn't be a bottleneck. To get a better idea of what kind of problem you're having, you can use Interlocked.Increment and Interlocked.Decrement to track the number of pending calls and see if it's being limited somewhere.
You could also substitute your real call with a call to a very simple method that you know will not have any bottlenecks, to see if the problem is in the client or server.