I'm new to Quartz.Net and I'm wondering what happens if a job is scheduled in the past? Is an exception thrown? Is it run immediately? I'm wondering if I need to guard for this condition when I schedule jobs.
You will get an exception if the trigger you are adding would never fire. There is a distinction here to note: you can schedule start time to be in the past but there needs to be some future time for the trigger to fire. So having start time of NOW()-1d is fine if you have firing happening after the time you add the trigger (EndTimeUtc in the future AND schedule that permits futher fires from now).
So you should check that GetNextFireTimeUtc returns non-null value for trigger you are adding.
Related
I've set up the quartz scheduler to ignore misfires and move on to the next fire time (using .WithMisfireHandlingInstructionNextWithRemainingCount() and .WithMisfireHandlingInstructionDoNothing()). This works fine but if there is no next fire time the trigger will just keep the old next fire time that has already misfired and wait for it to fire (it will never fire because it is in the past).
The way I'm testing this is pausing a trigger and waiting for the fire times to pass/misfire. The trigger's state is updated to COMPLETE only after resuming and remains in the database. I want the trigger to remove itself from the database (like it normally does when complete). I also want the trigger to complete without me having to resume the trigger but that's a bonus.
So the problem was I was setting the start time (using .StartAt() method) to the start time of the intervals I was using. For example, let's say it is currently 9am on June 23rd. If I had a trigger that runs daily starting at 3am then the start time of the daily interval is 3am. However, I was also setting the start time of the trigger to 3am, which is in the past. This ended up causing me many issues.
I am running workflow on the AWS console. I saw there is a Event Type called "TimerFired" in the console. What does it do?
TimerFired event is generated when timer scheduled through StartTimer decision fires. It also causes a new decision being scheduled to give decider chance to handle the timer event.
TL:DR; Is it possible to create a custom trigger that only fires if some flag is set? Is it possible to deploy the job with a trigger with a huge delay while we know a large data event is happening, and then deploy an update to the job with the trigger having a normal or no delay once that event is finished?
Following on from: Remove duplicates across window triggers/firings
The situation where this happens the most problematically (millions of duplicate firings) is when we're doing a backfill of old data. Given we know when this was happening I was wondering if we could implement a custom trigger that doesn't fire while a flag is set. Is that something that would be possible? Alternatively, could we deploy the job with a trigger that includes a huge delay while backfill is going on, and then issue an update with the normal trigger when it's finished?
Dataflow does not yet support custom triggers, or triggers based on some separate piece of metadata. However, you can change the frequency of a processing time trigger with Update; just change the value of the plusDelay() builder function and run with --update as normal.
In my application I use a winevent hook to get focus changes system-wide. Because there are no timing problems, I use an out-of-context hook, even if I know that it is slow. If there are multiple events fired quickly on after another, the system queues them and gives them to the hook callback function in the right order.
Now I would like to process only the newest focus change. So if there are already other messages in the queue, I want the callback function to stop and restart with the parameters of the newest message. Is there a way to do that?
When you receive a focus change, create an asynchronous notification to yourself, and cancel any previous notification(s) that may still be pending.
You can use PostMessage() and PeekMessage(PM_REMOVE) for that. Post a custom message to yourself, removing any previous custom message(s) that are still in the queue.
Or, you can use TTimer/SetTimer() to (re)start a timer on each focus change, and then process the last change when the timer elapses.
Either way, only the last notification will be processed once the messages slow down.
i want implement a windows services scheduled task.
I already created windows service. In a service i have implemented a timer.The timer is initialized at class interval. The timers interval is set in the start method of service and also it is enabled in the start method of the service. After timers elapsed event is fire i have done some actions.
My problem is that, i am in a dilemma. Lets say the action i have done in Elapsed event, lets say take one hour and the timers interval is set to half an hour. so there are chances that even if the previous call to elapsed event has not ended new call to elapsed event will occur.
my question will there be any conflict or is it ok or shall i use threads.
please give some advice
You can stop the timer at the begining of your long running method, then start it again at the end:
Timer.Change(Timeout.Infinite, Timeout.Infinite)
// do long task ...
Timer.Change(dueTime,period)