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https://issues.apache.org/jira/browse/HDFS-1353?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jakob Homan updated HDFS-1353:
------------------------------

    Attachment: HDFS-1353-y20-2.patch

Uploading updated patch.  We changed the fix a bit to not bump the RPC protocol 
version since it's a minor fix.  Not for commit to Apache.

> Remove most of getBlockLocation optimization
> --------------------------------------------
>
>                 Key: HDFS-1353
>                 URL: https://issues.apache.org/jira/browse/HDFS-1353
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: name-node
>    Affects Versions: 0.21.0
>            Reporter: Jakob Homan
>            Assignee: Jakob Homan
>             Fix For: 0.22.0
>
>         Attachments: Benchmarking results.xlsx, 
> HDFS-1353-optmized-wire-not-to-be-committed.patch, HDFS-1353-y20-2.patch, 
> HDFS-1353-y20.patch, HDFS-1353.patch
>
>
> <This description is not valid. See comment.>
> HDFS-1081 optimized the number of block access tokens (BATs) created in a 
> single call to getBlockLocations, as this is an expensive operation.  
> However, that JIRA put off another optimization which was then made possible, 
> which is to just send a single block access token across the wire (and 
> maintain a single BAT on the client side).  This JIRA is for implementing 
> that optimization.  Since a single BAT is generated for all the blocks, we 
> just write that single BAT to the wire, rather than writing n BATs for n 
> blocks, as is currently done.  This turns out to be a useful optimization for 
> files with very large numbers of blocks, as the new lone BAT is much larger 
> than was a BAT previously.

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