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https://issues.apache.org/jira/browse/HADOOP-17362?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Work on HADOOP-17362 started by Ahmed Hussein.
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> Doing hadoop ls on Har file triggers too many RPC calls
> -------------------------------------------------------
>
>                 Key: HADOOP-17362
>                 URL: https://issues.apache.org/jira/browse/HADOOP-17362
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: fs
>            Reporter: Ahmed Hussein
>            Assignee: Ahmed Hussein
>            Priority: Major
>
> [~daryn] has noticed that Invoking hadoop ls on HAR is taking too much of 
> time.
> The har system has multiple deficiencies that significantly impacted 
> performance:
> # Parsing the master index references ranges within the archive index. Each 
> range required re-opening the hdfs input stream and seeking to the same 
> location where it previously stopped.
> # Listing a har stats the archive index for every "directory". The per-call 
> cache used a unique key for each stat, rendering the cache useless and 
> significantly increasing memory pressure.
> # Determining the children of a directory scans the entire archive contents 
> and filters out children. The cached metadata already stores the exact child 
> list.
> # Globbing a har's contents resulted in unnecessary stats for every leaf path.
>  



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