[jira] [Created] (HIVE-21686) Brute Force eviction can lead to a random uncontrolled eviction pattern.

["slim bouguerra (JIRA)" <ji...@apache.org>]

slim bouguerra created HIVE-21686:
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             Summary: Brute Force eviction can lead to a random uncontrolled eviction pattern.
                 Key: HIVE-21686
                 URL: https://issues.apache.org/jira/browse/HIVE-21686
             Project: Hive
          Issue Type: Bug
            Reporter: slim bouguerra
            Assignee: slim bouguerra


Current logic used by brute force eviction can lead to a perpetual random eviction pattern.
For instance if the cache build a small pocket of free memory where the total size is greater than incoming allocation request, the allocator will randomly evict block that fits a particular size.
This can happen over and over therefore all the eviction will be random.
In Addition this random eviction will lead a leak in the linked list maintained by the policy since it does not know anymore about what is evicted and what not.




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