Can Quartz JobExecutionContext getScheduledFireTime() return null value? - quartz-scheduler

I am trying to call getScheduledFireTime() on JobExecutionContext object of Quartz. But, I am getting a null value.
Additional info: I am using quartz-mongodb jobstore.
This happens only during the first time a trigger fires.
Is it correct? If so, under what situations does Quartz return null for this value?

After a sleepless night, I found out that it is a bug in quartz-mongodb jobstore. Created a pull request with the fix. Waiting for the next release of the job store.

Related

Query not invalidated correctly in react-query

I am doing a mutation with the useMutation hook of React-Query. Inside the onSuccess callback, I am calling queryClient.invalidateQueries(['key']) to invalidate another query. That other query gets called again but the data is incorrect (it should be updated). I took a look at the Network tab and seems like the second query is made before the first one succeeds as you can see in the following image:
In the backend, I put a sleep function to wait before sending the response of the second query. It worked and the second query actually returned the correct data, meaning there is some kind of race condition just because the second query is not sent after the first one succeeds.
When I use onSettled, the query is made after the first one, but I want to use onSuccess because onSettled also fires when there is an error.
I figured out what was happening. I was not returning a Promise in the queryFn function of react-query, so React Query couldn't resolve it and know when the first query finished.

Firestore trigger temporal information

Hi so i understand firestore write triggers run out of order with respect to time. Is is possible to get timestamp information on when a write occured within the trigger functions execution context?
If you're using the Firebase CLI to deploy, every background function is delivered an EventContext object as its second parameter. You can use its timestamp property. Or, you can have the client write it into the document.
I assume something similar is available for the context object provided to code deployed by gcloud.

How to resolve: The transaction operation cannot be performed Exception

I am getting this error, and I have not been able to resolve:
System.Data.SqlClient.SqlException: 'The transaction operation cannot be performed because there are pending requests working on this transaction.'
What is going on is that a usual data operation is taking place as part of a Controller Action.
At the same time, there is a Filter that is running that logs the action to a database.
this._orderEntryContext.ServerLog.Add(serverLog);
return this._orderEntryContext.SaveChanges() > 0;
This is where the error occurs.
So it seems to me that there is two SaveChanges going on at the same time, and so the transaction gets fouled up.
Not sure how to resolve. They are both using the same context that is gotten through DI. A workaround was to create a second context manually, but I would rather stick to the DI pattern. But I don't know how to create a second Db Context in DI, or even if that is a good idea.
Perhaps I should be using SaveChangesAsync() on both calls to ensure that they do not step on each other?
Turns out the answer to this was to make the Context a transient service:
services.AddDbContext<OrderEntryContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")), ServiceLifetime.Transient);
Then, I changed all repositories to also be transient:
services.AddTransient<AssociateRepository, AssociateRepository>();

playframework 1.2.x: await / async and JPA transactions

I have a PUT request that is too long to run. I'd like to make it async, using continuations (await/promise feature).
I create a job (LongJobThatUpdatesThePassedEntity) that modifies my entity
public static void myLongPut(#required Long id, String someData) {
MyJpaModel myJpaModel = MyJpaModel.findById(id);
//straightforward modifications
updateMyJpaModel(someData);
myJpaModel.save();
//long processing modifications to entity, involving WS calls
Promise<String> delayedResult = new LongJobThatUpdatesThePassedEntity(id).now();
await(delayedResult);
render(myJpaModel.refresh());
}
How are the DB transactions managed?
is there a commit before the job's call?
the job has it's own DB transaction?
if there is an issue in the LongJobThatUpdatesThePassedEntity that rollsback, the modifications done in updateMyJpaModel are persisted?
can I do render(myJpaModel.refresh()) at the end?
will it contain the straighforward modifications and the long ones?
thank's
I can answer most of your question for Play 1.4.3, which is the version I'm currently using. I don't expect that much has changed since Play 1.2.
How are the DB transactions managed?
Play! handles the transactions for jobs and controller actions using an "invocation", which is a Play-specific concept. In short, for any invocation, each plugin gets a chance to do some setup and cleanup before and after the invoked method runs. For database access, the JPAPlugin.withinFilter method starts and closes the transaction using the JPA class's helper methods.
is there a commit before the job's call?
When you call await(Future<T>), it has the effect of closing the current transaction and starting a new one. The specific mechanism is that it throws a "Suspend" exception, which bubbles up to PlayHandler$NettyInvocation and causes the afterInvocation callbacks to be called. This causes JPAPlugin.afterInvocation to call
JPA.closeTx() which either commits or rollsback the transaction, as appropriate.
When the Job exits and the await() continuation is resumed. This is also handled as an invocation, so the transaction is started in the same way as before, using JPAPlugin.withinFilter(). However, unlike before, the controller action is not the target of the invocation, but instead ActionInvoker.invoke() calls invokeWithContinuation, which restores the saved continuation state and resumes execution by returning from await().
JPA.withTransaction looks like it has some special logic to retain the same entity manager across the continuation suspend/resume. I think without this, you wouldn't be able to call refresh().
In your code, I think there's a race condition between when await() closes the transaction and the Job starts its transaction. That is, it's possible that the Job's transaction begins before the controller commits the "before await" transaction. To avoid this, you can explicitly call JPA.closeTx() before calling Job.now().
Based on code inspection, it looks like the way Play! is implemented, it so happens that the Job will exit and the Job's transaction will be closed before the "after await()" transaction is opened. I don't know if any
documentation that says this is an intended part of the await() contract, so if this is essential for your appliaction, you can avoid using undocumented behavior by committing the transaction just before your Job.doJobWithResult() method returns.
the job has it's own DB transaction?
Yes, unless its annotated to not have a transaction.
if there is an issue in the LongJobThatUpdatesThePassedEntity that rollsback, the modifications done in updateMyJpaModel are persisted?
Based on the explanation above, each of the three transactions are independent. If one is rolled back, I don't see how it would affect the others.

Obtain ServiceDeploymentId in TrackingParticipant

In WF4, I've created a descendant of TrackingParticipant. In the Track method, record.InstanceId gives me the GUID of the workflow instance.
I'm using the SqlWorkflowInstanceStore for persistence. By default records are automatically deleted from the InstancesTable when the workflow completes. I want to keep it that way to keep the transaction database small.
This creates a problem for reporting, though. My TrackingParticipant will log the instance ID to a reporting table (along with other tracking information), but I'll want to join to the ServiceDeploymentsTable. If the workflow is complete, that GUID won't be in the InstancesTable, so I won't be able to look up the ServiceDeploymentId.
How can I obtain the ServiceDeploymentId in the TrackingParticipant? Alternately, how can I obtain it in the workflow to add it to a CustomTrackingRecord?
You can't get the ServiceDeploymentId in the TrackingParticipant. Basically the ServiceDeploymentId is an internal detail of the SqlWorkflowInstanceStore.
I would either set the SqlWorkflowInstanceStore to not delete the worklow instance upon completion and do so myself at some later point in time after saving the ServiceDeploymentId with the InstanceId.
An alternative is to use auto cleanup with the SqlWorkflowInstanceStore and retreive the ServiceDeploymentId when the first tracking record is generated. At that point the workflow is not complete so the original instance record is still there.