Improve support in PDI Job Watcher for Jobs that do not use CPU during the interval

By design, the Job Watcher performance data collector does not collect data on jobs that do not use CPU during the interval.

Jobs that are blocked by waits such as a database record lock or an object lock are often in a long wait and do not use CPU for several intervals. There types of blocked waits are also some of the most common type of waits that need investigation by the average user.

However, in PDI, working with these jobs/threads is problematic.

First of all, the chart that shows the job/thread over time gives no clue that there are missing intervals. It looks like a normal chart. But if you hover over a bar, the flyover shows the interval number and going from one bar to another you can figure out that there are missing intervals. These charts should better visually convey the amount of time the thread was in a blocked wait.

Second, when displayng Interval Details for these threads, you cannot go from one interval to the next - the next interval results in an error. You have to go back to the signature of that thread (which reloads that chart) to display the interval details for the next available interval. The interval details will be the same until the thread is out of the blocked wait - so displaying the same wait information when going from interval to interval, until the interval when the thread uses CPU, would greatly improve the usability.

Given that jobs blocked by long waits are one of the more common reasons for investigating job watcher data, the usability of investigating these jobs needs to be improved.