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I am a java application with JFR enable, which generated the attached file I am new to using JFR can so I need help reading the file. I need help reading the file. When did the application start and stopped, how much memory was used, what are the orange and pink bars what do they indicate?

There is no data after 1:28:00 PM. what does that mean?

enter image description here

Kire Haglin
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Neha
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2 Answers2

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It means exactly what you see, there has been no data. Maybe it makes it clear if you see some examples on this topic.

I recommend you the following videos:

  1. Introduction to JDK Flight Recorder by Java
  2. Short Java Mission Control demo by Java
  3. Complete Youtube Playlist explaining Java Mission Control by Oracle Learning
  4. Tutorial by Ajay Wadhara

A few weeks ago I had the same questions like you and found these videos on youtube. They are really helpful.

Matécsa Andrea
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A flight recording can be taken from any time period when your application was running. Hence, JMC cannot (usually) know when your application was stopped. Sometimes, if you did indeed emit the flight recording on JVM shutdown (for example using command line parameters), you can have a VM Shutdown event, and then you can truly know when your application was shutting down.

JVM start time, if you need it, can be seen under JVM Internals: enter image description here

Mostly JDK Mission Control concerns itself with the events that have been captured. You can look at the time range covered by any selection of events in the properties view: enter image description here

For the red bars that cut through all the charts, they correspond to stop-the-world phases, for example by GC. You can hover over them to get more info: enter image description here

If there is no data, there simply is no data. ;) Maybe you had a timed recording that stopped capturing that particular kind of data after that time?

Hirt
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  • The way JMC displays charts is usually by taking the start time of the first event in the recording and the end time of the last event as the min/max of the y-axis. This means that the chart can look much larger than the time you asked to be profiled. We're working on helping reduce the confusion regarding this in JMC 8.0.0. – Henrik Dafgård May 28 '20 at 12:44