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https://issues.apache.org/jira/browse/HDFS-516?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jay Booth updated HDFS-516:
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Status: Patch Available (was: Open)
Here's the initial patch. I have some pretty decent byte-consistency and
integration tests wrapping it but no actual applications built using it. I
started on a SequenceFileSearcher that implemented binary search but dealing
with the sync points was sticky so it's not working yet (and commented out,
with associated failing test). I'm hoping to get that working in the next
couple weeks when I have some time as an example along with doing a performance
comparison between nutch FsDirectory using DistributedFileSystem and
RadFileSystem to see if this shows the gains that I'm thinking it will. My
only change to core HDFS was to add getFile() to FSDatasetInterface so that the
RadNode (plugged into datanode via ServicePlugin) can open FileChannels.
> Low Latency distributed reads
> -----------------------------
>
> Key: HDFS-516
> URL: https://issues.apache.org/jira/browse/HDFS-516
> Project: Hadoop HDFS
> Issue Type: New Feature
> Reporter: Jay Booth
> Priority: Minor
> Attachments: radfs.patch
>
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> I created a method for low latency random reads using NIO on the server side
> and simulated OS paging with LRU caching and lookahead on the client side.
> Some applications could include lucene searching (term->doc and doc->offset
> mappings are likely to be in local cache, thus much faster than nutch's
> current FsDirectory impl and binary search through record files (bytes at
> 1/2, 1/4, 1/8 marks are likely to be cached)
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