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Date: Mon, 29 Feb 2016 23:01:18 +0000 (UTC)
From: "Jing Zhao (JIRA)" <jira@apache.org>
To: hdfs-dev@hadoop.apache.org
Message-ID: <JIRA.12945657.1456786835000.177658.1456786878173@Atlassian.JIRA>
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Subject: [jira] [Created] (HDFS-9876) shouldProcessOverReplicated should not
 count number of pending replicas
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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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