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From "Jing Zhao (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HDFS-9876) shouldProcessOverReplicated should not count number of pending replicas
Date Mon, 29 Feb 2016 23:01:18 GMT
Jing Zhao created HDFS-9876:
-------------------------------

             Summary: shouldProcessOverReplicated should not count number of pending replicas
                 Key: HDFS-9876
                 URL: https://issues.apache.org/jira/browse/HDFS-9876
             Project: Hadoop HDFS
          Issue Type: Sub-task
            Reporter: Takuya Fukudome
            Assignee: Jing Zhao


Currently when checking if we should process over-replicated block in {{addStoredBlock}},
we count both the number of reported replicas and pending replicas. However, {{processOverReplicatedBlock}}
chooses excess replicas only among all the reported storages of the block. So in a situation
where we have over-replicated replica/internal blocks which only reside in the pending queue,
we will not be able to choose any extra replica to delete.

For contiguous blocks, this causes {{chooseExcessReplicasContiguous}} to do nothing. But for
striped blocks, this may cause endless loop in {{chooseExcessReplicasStriped}} in the following
while loop:
{code}
      while (candidates.size() > 1) {
        List<DatanodeStorageInfo> replicasToDelete = placementPolicy
            .chooseReplicasToDelete(nonExcess, candidates, (short) 1,
                excessTypes, null, null);
{code}



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