Threading.Task.Run Submits Twice But Only On Some Calls

Question

Friends: this problem has me flummoxed.

This code submits the same job twice UNLESS I log it!

' optionally log to a textfile before call
If bLog Then LogProcess("Before run")

' this only processes once regardless of 
ExecuteSQL($"UPDATE [Process] SET [timesRepeated] += 1, [dateStarted] = '{Now}' WHERE [id] = {iID}")

Dim oBackground As New Background

' this thing spawns two of the some - but not all - jobs!
Dim t1 As Task = Task.Run(Sub() CallByName(oBackground, sProcessKey, CallType.Method, iID))

' optionally log to a textfile following call
If bLog Then LogProcess("After run")

This happens as part of a background processing routine that is called by an internal timer.

I've verified that the timer is only spawned once and only fires once per "heatbeat".

If this routine is called with bLog = True, I get single executions. If bLog = False, SOME processes (sProcessKey) get called twice at the exact same time. I have logging in these routines as well.

Any thoughts?

Thanks in advance.

Answer 1

I hope this helps someone else. It's not a solution, only a work-around:

Since delaying processing by just a bit (via logging in this case) worked, I added a snooze factor, thusly:

If bLog Then 
   LogProcess("After run")
Else
   Thread.Sleep(1000)
End If

This solves the issue, but obviously, delays processing for 1 second.