I think it depends on your configurations. - Are you using on-heap/off-heap managed memory? (configured by 'taskmanager.memory.off-heap', by default is false)
- Is managed memory pre-allocated? (configured by 'taskmanager.memory.preallocate', by default is ffalse) If managed memory is pre-allocated, then the allocated memory segments will never be released. If it's not pre-allocated, memory segments should be released when the task is finished, but the actual memory will not be de-allocated until next GC. Since the job is finished, there may not be enough heap activities to trigger the GC. If on-heap memory is used, you may not be able to observe the decreasing of TM memory usage, because JVM heap size does not scale down. Only if off-heap memory is used, you might be able to observe the decreasing of TM memory usage after a GC, but not from a jmap dump because jmap dumps heap memory usage only. Besides, I don't think you need to worry about whether memory is released after one job is finished. Sometimes flink/jvm do not release memory after jobs/tasks finished, so that it can be reused directly by other jobs/tasks, for the purpose of reducing allocate/deallocated overheads and optimizing performance. Thank you~ Xintong Song On Thu, Oct 10, 2019 at 7:55 PM Timothy Victor <vict...@gmail.com> wrote: > After a batch job finishes in a flink standalone cluster, I notice that > the memory isn't freed up. I understand Flink uses it's own memory > manager and just allocates a large tenured byte array that is not GC'ed. > But does the memory used in this byte array get released when the batch > job is done? > > The scenario I am facing is that I am running a series of scheduled batch > jobs on a standalone cluster with 1 TM and 1 Slot. I notice that after a > job is complete the memory used in the TM isn't freed up. I can confirm > this by running jmap dump. > > Has anyone else run into this issue? This is on 1.9. > > Thanks > > Tim >
