Difference between “on-heap” and “off-heap”

by

The on-heap store refers to objects that will be present in the Java heap (and also subject to GC). On the other hand, the off-heap store refers to (serialized) objects that are managed by EHCache, but stored outside the heap (and also not subject to GC). As the off-heap store continues to be managed in memory, it is slightly slower than the on-heap store, but still faster than the disk store.

The internal details involved in management and usage of the off-heap store aren’t very evident in the link posted in the question, so it would be wise to check out the details of Terracotta BigMemory, which is used to manage the off-disk store. BigMemory (the off-heap store) is to be used to avoid the overhead of GC on a heap that is several Megabytes or Gigabytes large. BigMemory uses the memory address space of the JVM process, via direct ByteBuffers that are not subject to GC unlike other native Java objects.

More Related Contents:

  1. Recommendations for a heap analysis tool for Java? [closed]
  2. Heap space out of memory
  3. Java Refuses to Start – Could not reserve enough space for object heap
  4. Steps in the memory allocation process for Java objects
  5. How can I create a memory leak in Java?
  6. Increase heap size in Java
  7. Java using much more memory than heap size (or size correctly Docker memory limit)
  8. Get OS-level system information
  9. How to find a Java Memory Leak
  10. Java maximum memory on Windows XP
  11. How do I monitor the computer’s CPU, memory, and disk usage in Java?
  12. Using HeapDumpOnOutOfMemoryError parameter for heap dump for JBoss
  13. Calculate size of Object in Java [duplicate]
  14. java.lang.OutOfMemoryError: Java heap space
  15. How are integers internally represented at a bit level in Java?
  16. How to set the maximum memory usage for JVM?
  17. boolean[] vs. BitSet: Which is more efficient?
  18. Setting JVM heap size at runtime
  19. General strategy to resolve Java memory leak?
  20. Memory leak when redeploying application in Tomcat
  21. is memory leak? why java.lang.ref.Finalizer eat so much memory
  22. Does variable = null set it for garbage collection
  23. Why does the (Oracle) JVM have a fixed upper limit for memory usage (-Xmx)?
  24. Why does appending “” to a String save memory?
  25. Understanding max JVM heap size – 32bit vs 64bit
  26. Can the JVM max heap size be dynamic?
  27. How to determine the size of an object in Java
  28. java.lang.OutOfMemoryError: Java heap space with NetBeans
  29. Java very large heap sizes [closed]
  30. How to set Java heap size (Xms/Xmx) inside Docker container?

Leave a Comment