Object eviction

Ray Core
1

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Hi there,

I wanted to ask about the concept of object eviction. Do I undestand correctly that Ray evicts an object from the shared store and stores it in-process memory of a worker? Or does eviction mean complete removal of the object?

2

It’s in this order:

  1. if you put some (big enough) objects to Ray, it’s in shared memory
  2. during the work, an object may have multiple copies in different workers, and Ray may choose to remove some copies on memory pressure. This will always keep at least 1 copy of them
  3. for a worker, if it’s on memory pressure, it may choose to spill which means it moves the objects to disk.
  4. If an object has no references anywhere, it can be deleted including the last copy.
3

Hi @Ruiyang_Wang, thanks for the response. Just one clarification. Does eviction mean that an object is removed from shared memory and there are no references neither in RAM nor on disk?