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https://issues.apache.org/jira/browse/HADOOP-803?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12466546
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Raghu Angadi commented on HADOOP-803:
-------------------------------------
The bug is in the following patch. Very costly oversight: The does not affect
equals() but affects Block.comparedTo().
public int compareTo(Object o) {
- Block b = (Block) o;
- if (getBlockId() < b.getBlockId()) {
- return -1;
- } else if (getBlockId() == b.getBlockId()) {
- return 0;
- } else {
- return 1;
- }
+ long diff = getBlockId() - ((Block)o).getBlockId();
+ return ( diff < 0 ) ? -1 : ( ( diff > 0 ) ? 1 : 0 );
}
e.g: 'diff' wont be < 0 when blocks ids are LONG_MAX and -10.
changing this to following fixes it.
+ Block b = (Block)o;
+ return ( blkid < b.blkid ) ? -1 :
+ ( ( blkid > b.blkid ) ? 1 : 0 );
Now TestSmallBlocks patch does not fail.
> Reducing memory consumption on Namenode : Part 1
> ------------------------------------------------
>
> Key: HADOOP-803
> URL: https://issues.apache.org/jira/browse/HADOOP-803
> Project: Hadoop
> Issue Type: Bug
> Components: dfs
> Reporter: Raghu Angadi
> Assigned To: Raghu Angadi
> Fix For: 0.11.0
>
> Attachments: block-refs-2.patch, block-refs-3.patch,
> block-refs-5.patch, HADOOP-803.patch
>
>
> There appears to be some places in Namenode that allow reducing memory
> consumption without intrusive code or feature changes. This bug is an initial
> attempt making those changes. Please include your thoughts as well.
> One change I am planning to make :
> Currently one copy of each block exists for each of the replicas and one copy
> for blockMap. I think they are all supposed to be same.
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