quarkus-scheduler: Timestamps of the current run and the previous run are indistinguishable

[JBartscher]

Hi all,

I have noticed a peculiarity in the extension quarkus-scheduler that I am not sure if it is a bug or if I am simply using the lib incorrectly.
The issue is that the quarkus-scheduler uses the ScheduledExecution class to map the context of a task scheduled by the scheduler. This allows the execution time to be determined using the getScheduledFireTime() function. The trigger can also be accessed using getTrigger(). This in turn offers the function getPreviousFireTime() to terminate the last run of the task.

Now the curious thing: these two timestamps are identical.

Am I using the scheduler and its methods incorrectly or is this an actual bug?

Ive set up a minimal example to test this behavior if anyone want to have a look at it.
https://github.com/JBartscher/scheduler-ctx-timestamp-bug

Ive tested it with Quarkus in Version 3.10.1

[quarkus-bot[bot]]

/cc @manovotn (scheduler), @mkouba (scheduler)

[manovotn]

I found a very similar Quarkus issue that might be of interest to you - #37567

@mkouba's answer there says:

The reason why the Trigger#getPreviousFireTime() is sometimes the same as ScheduledExecution.getFireTime() is that trigger is a mutable object that reflects the current state whereas the ScheduledExecution is immutable. In other words, ScheduledExecution.getFireTime() always returns the same value whereas Trigger#getPreviousFireTime() returns the actual value.

I also tried looking into Quartz's API which have very similar methods (see here) but nonexistent javadoc to explain what the diff should be :-/

[mkouba]

Yes, so the difference between Trigger and ScheduledExecution is that the trigger is bound to a scheduled method/job whereas the scheduled execution is bound to a particular invocation of @Scheduled method or job registered programmatically with Scheduler.newJob().

The trigger is a stateful object, that is used to test if a scheduled job should be executed. In other words, both Trigger#getNextFireTime() and Trigger#getPreviousFireTime() may return different values in time.

The ScheduledExecution, on the other hand, is an immutable snapshot and both ScheduledExecution#getFireTime()and ScheduledExecution#getScheduledFireTime() always returns the same value.

Note that you can also obtain the trigger with the Scheduler#getScheduledJob(String) method, i.e. outside a specific scheduled execution.