What is the internal mechanism for persisting data using Quartz Scheduler?
I went through internet but didn't find clear description.
It would be great if you suggest the same to work in hibernate platform.
When you use Quartz Scheduler in your project you should have a file for its properties which is called quartz.properties. In this file you should determine your persistence mechanism by using parameter: org.quartz.jobStore.class
The value for this parameter can be the followings:
org.quartz.impl.jdbcjobstore.JobStoreCMT: it means that you want to persist in a database and transactions are managed by a container (Like Weblogic, JBoss, ...)
org.quartz.impl.jdbcjobstore.JobStoreTX: it means that you want to persist in a database and transactions are NOT managed by a container. this option is used mostly when you run Quartz Scheduler as a standing alone application.
org.quartz.simpl.RAMJobStore: This option actually is not recommended in production environment because according this parameter Quartz persists jobs and triggers just in RAM!
org.terracotta.quartz.TerracottaJobStore: The last option is using Terracotta Server as your persistence unit, Quartz says that it is the fastest way.
I myself prefer first option, it is straightforward and more reliable I think.
You can read more about this configuration here.
And about hibernate, quartz will manage the persistence tasks, like rollback and persist, and you wont being involved in this process.
Related
I've been looking at using service fabric as a platform for a new solution that we are building and I am getting hung up on data / stage management. I really like the concept of reliable services and the actor model and as we have started to prototype out some things it seems be working well.
With that beings said I am getting hung up on state management and how I would use it in a 'real' project. I am also a little concerned with how the data feels like a black box that I can't interrogate or manipulate directly if needed. A couple scenarios I've thought about are:
How would I share state between two developers on a project? I have an Actor and as long as I am debugging the actor my state is maintained, replicated, etc. However when I shut it down the state is all lost. More importantly someone else on my team would need to set up the same data as I do, this is fine for transactional data - but certain 'master' data should just be constant.
Likewise I am curious about how I would migrate data changes between environments. We periodically pull production data down form our SQL Azure instance today to keep our test environment fresh, we also push changes up from time to time depending on the requirements of the release.
I have looked at the backup and restore process, but it feels cumbersome, especially in the development scenario. Asking someone to (or scripting the) restore on every partition of every stateful service seems like quite a bit of work.
I think that the answer to both of these questions is that I can use the stateful services, but I need to rely on an external data store for anything that I want to retain. The service would check for state when it was activated and use the stateful service almost as a write-through cache. I'm not suggesting that this needs to be a uniform design choice, more on a service by service basis - depending on the service needs.
Does that sound right, am I overthinking this, missing something, etc?
Thanks
Joe
If you want to share Actor state between developers, you can use a shared cluster. (in Azure or on-prem). Make sure you always do upgrade-style deployments, so state will survive. State is persisted if you configure the Actor to do so.
You can migrate data by doing a backup of all replica's of your service and restoring them on a different cluster. (have the service running and trigger data-loss). It's cumbersome yes, but at this time it's the only way. (or store state externally)
Note that state is safe in the cluster, it's stored on disk and replicated. There's no need to have an external store, provided you do regular state backups and keep them outside the cluster. Stateful services can be more than just caches.
Exploring (Ado)JobStore (data base job store in general) I met subjects like clustering, load balancing and sharing jobs' work data state across multiple applications.
But I think I didn't find a JobStore subject that covers my scenario.
I need to run Quartz Jobs in Windows Service and I need to be able to change configuration of Triggers in other application (in Admin panel in web application) and the Triggers to be applied by the Quartz in my Windows Service automatically (Quartz tracks changes and applies them).
Is it possible to do this by using AdoJobStore/Clustering mechanism? I mean in terms of JobStore's features, so by using Quartz scheduler API. Not by using SQL and changing data in Quartz tables directly or any other workarounds (according to Quartz's Best Practices doc).
The Quartz.NET scheduler can be accessed remotely, independently of job stores. Since you already have a web app you can add a reference to the remote scheduler and use the API to administer jobs, triggers etc.
I'm learning Quartz and I've gone through the tutorials. I used the RAM JOB store. Now I want to move it to jdbc job store. I've created database and configured it. But the scheduler has not started. What is the values that I've to populate it with the database.
You don't need to populate the database. It is highly recommended to NOT write directly to quartz tables: http://quartz-scheduler.org/documentation/best-practices.
Just configure the scheduler programmatically by adding triggers and job details as described in example: http://quartz-scheduler.org/documentation/quartz-2.2.x/examples/Example1.
Quartz can store jobs on database so its not volatile.
But if i have two application(web-application and web service) ,
how can i share this store between applications.
That is if one application select a job to run other application informed.And when one application fail it will continue to run
I realise this is a late reply, but for anyone else who might find this useful...
Quartz is designed with clustered environments in mind, specifically for what you're asking. You can point both of your applications (web service and web application) to the same Quartz job database, and Quartz itself will manage locking the jobs so that they still only run according to their schedule.
In your Quartz config make sure you're using:
org.quartz.jobStore.class=org.quartz.impl.jdbcjobstore.JobStoreTX
... And then duplicate the Quartz setup across both your applications, ensuring they both point to the same database.
I think it should take care of itself! Search for "Quartz clustering" if you need more info.
I've been playing with examples I downloaded with the book Drools JBoss Rules 5.0. To my relief they work :) Drools Flow has been my point of interest as a possible workflow engine replacement.
As I'm trying to wrap my head around things, I've been wondering how a premature death of a rulesflow process gets restarted? What I'm mean is say a process is bouncing from one node to another like expected, then the containing process dies due to a crash, restart or whatever. Is the current node/place of the ruleflow process retained, and can it just continue from that point on system restart? If so how?
The group I work for is very Java EE centric with JBoss being our favorite application server. I see examples of Drools leveraging Spring's persistence and bean lookup support.
Are there examples of doing the same with JBoss?
If you persist the state of the process instances and tasks in the database. Even if the VM was down and restart again, you can retrieve the process instances.
Use the
To create the session
ksession = JPAKnowledgeService.newStatefulKnowledgeSession(kbase,null,env)
To load the session with the session id.
ksession = JPAKnowledgeService.loadStatefulKnowledgeSession( sessionId, kbase,
You only need to know the session id. Session information will be store in SessionInfo table. Download the example project below.
http://dl.dropbox.com/u/2634115/drools-test.zip
The example is using Btm with H2 database, it also work well with mysql-connector-java-5.1.13 with Btm. Note that the process that are complete will be automatically deleted from the database.
You are looking at the basic concept of Process Migration. During what is known as strong migration, a process can be stopped on one machine and the entire state of the process migrated to another machine (including the program counter and all existing stacks). Before you go thinking that this is completely insane, think about this from a JVM perspective. Since you're application is already being run in virtual hardware; it isn't hard to stop the application and pick it back up where it left off since it is completely virtualized.
If you would like another example, look at VMWare; an entire machine can be paused and migrated to another machine and started again. It's very interesting stuff and usually relates mainly to Distributed Computing where you might have hundreds of agents that need to migrate from machine to machine as some go down for maintenance.
I realize that I didn't give an example of this through JBoss; but giving a background on what exactly you're looking for can give you a much better insight into what to look for going forward.