Timer trigger not fired on the schedule if function execution takes longer than the specified schedule.

[safihamid]

Created a timer trigger function with the schedule of 1 minute and the body of the function had a CPU intensive operation taking 2 minutes to complete.

The function was being called on a random schedule longer than 2 minutes.

If this is by design because timers run singleton then we should document this.

Here was my function:
using System;

public static void Run(TimerInfo myTimer, TraceWriter log)
{
log.Info($"C# Timer trigger function executed at: {DateTime.Now}");
DateTime now = DateTime.Now;

  int k = 1;
  int seconds = 120;

    while (DateTime.Now.Subtract(now) < TimeSpan.FromSeconds(seconds))
    {
        for (int i = 0; i < 1000; i++)
        {
                k += i ;
        }
    }

log.Info($"C# Timer trigger finished function execution at: {DateTime.Now}");
}

[mathewc]

If your function execution takes longer than the timer interval, another execution won't be triggered until after the current invocation completes. The next execution is scheduled after the current execution completes.

This is mentioned in the doc here.