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Activiti BPMN Engine: store custom property in Database

i use the latest Acitiviti 5.22.0 engine (to be more concrete i use Alfresco Process Services 1.6.3) and i have implemented a Spring bean that gets executed every 10 minutes to generate a JSON representation of all my processes (process name, startDate, endDate, current taskName(s) and assignee(s)), to send them to an audit server. The problem is, that i only need to send all changed processes since the last run.
I do not want to send the JSON as soon as a process changes but to do a batch update of my audit system every 10 minutes.
To accomplish this, i've tried different approaches. My latest one:
Create a event listener bean that listens to all PROCESS_STARTED, PROCESS_COMPLETED, PROCESS_CANCELLED, TASK_COMPLETED, ...
Every time the event is triggered, store a process variable "_dirty" and set it to true
Every 10 minutes (wenn my JSON-bean is executed) query for all processes with the "_dirty" variable set to true
After sending the JSON to the audit system, set all "_dirty" process variables to false.
The problem with this approach: I am not able to update the "_dirty" variable after a process is ended. At least i don't know how.
My second approach would be to to store the processInstanceId on every event into a "global" property, but i don't know how to store this "global" property into database in case the server restarts. Is there a way to persist a property or an Entity into DB without creating an extra table, DAO, etc.?
Any ideas on how to solve this task? All tips are very much appreciated!

AFAIK, There's no such option
But you look at this. and see if it can be helpful in your case.
https://www.activiti.org/userguide/#_database_tables

As Linus suggested: This is not possible, so I needed some completely different approach.
I am creating an Ad-Hoc task now and store my properties as a local task variable. The Ad-Hoc task is owned by a system account and not assigned to anybody. This way I can make sure, no one of my real users tries to "complete" the task. Also I've written some code to generate the task if needed, so in case i want to clean it, it is created automatically the next time i want to store data.
Creating an Ad-Hoc task is quite easy by using org.activiti.engine.TaskService autowiring into my class.
Task task = taskService.newTask();
task.setDelegationState(DelegationState.PENDING);
task.setName("Some name goes here");
task.setTenantId("your tenant id (if any)");
task.setOwner("your system accounts ID");
task.setCategory("i use a special category to later query for the task");
taskService.saveTask(task);
After saving the task to the database, I can use the taskService to store and retrieve variables like this:
taskService.setVariableLocal(task.getId(), "variableKey", "variableValue");
Or query for the task like this:
Task task = taskService.createTaskQuery().taskDelegationState(DelegationState.PENDING).taskCategory("your special category").singleResult();
Not a very nice solution (I recommend having the task cached in a bean or something, so you don't need to query it all the time or even cache its values or something), but it works.

Alternative to checking database value in a while loop

I have a scenario where I check for a specific value in the Database every 10 seconds or so. And, if the value is YES, then I execute a bunch of shell scripts from a Java application.
Now, the value in database is only updated to YES once in a while depending on the user submitting a job on a web page. Therefore, running a while loop to check for this value in database seems to be a very bad design and I would like to implement a much cleaner approach using listeners (Observer design pattern).
How would such an implementation look like? Any examples I can follow to do this?

Yes there is much better job. So there is something called binlog reader in mysql. Thats how master and slave sync is done in mysql cluster database.
So either you write your own logic over https://github.com/shyiko/mysql-binlog-connector-java which gets all the chane event on table
or use https://github.com/zendesk/maxwell to read events from particular table and whenver any change in value is there check if it matches your condition and excute the script or java application on basis of that instead of running it as a cron.

The general idea is to use DB triggers, register DB listener from Java side and be notified from DB side when some event has happened.
Pls review proposed solutions
How to implement a db listener in Java

Spark window function with synthetic timestamp?

Say I have a datafile with records where each record has a timestamp, like this:
foo,bar,blaz,timestamp1
foo,flibble,baz,timestamp2
bleh,foo,gnarly,timestamp3
...
and I want to process this using Spark, in a way that requires using the window() function. Is there any way to read these records, and get each one into the DStream so that the timestamp that will be used by the window() function is provided by my code explicitly (based on parsing the timestamp field in the input records in this case)?

No, the default Spark processing is based on the system time. And if you want to build the window using the event time. I suggest you use up "updateStateByKey" function to handle the logic inside the update function.

How to update table value based on the time line

Can anyone please suggest me the best approach for my requirement? I need to automatically update the table value after some specified time, using Java and MySQL as the database.

Using Quartz scheduler you can achieve this. You need to create one job and run that job at the required time so that it will fetch the data from the database and according to that you will do what's needed.
Quartz Scheduler Tutorial

Create a timer in Java.
Add a task to timer that updates value to MySQL.
Start timer
Example of Java Timer API: here

How to make a database listener with java?

Greetings all
I want to do something like a trigger or a listener (I don't know what) that will listen on a specific database table, and with each new record inserted on this table, do some java code, I mean that it detects that a new record was inserted and get it's data if it's possible
I need some guide about how this process can be accomplished ?
I am using Spring-Hibernate-PostgreSQL

This is what LISTEN/NOTIFY was created for.
The only drawback is that you will need to have some kind of background thread that polls the database on a regular basis to see if any notifications are available.
You can also use the code from the Postgres Wiki to have a starting point

I assume you mean that the DB content is added through your hibernate code.
If so, consult this previous answer of mine for how to set up Hibernate Event Listeners with Spring.
Otherwise, a-horse-with-no-name's answer should be best.

You could add an Interceptor to your Hibernate configuration to detect save events.