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https://issues.apache.org/jira/browse/HBASE-26032?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Wei-Chiu Chuang updated HBASE-26032:
------------------------------------
    Priority: Minor  (was: Major)

> Make HRegion.getStores() an O(1) operation
> ------------------------------------------
>
>                 Key: HBASE-26032
>                 URL: https://issues.apache.org/jira/browse/HBASE-26032
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Wei-Chiu Chuang
>            Assignee: Wei-Chiu Chuang
>            Priority: Minor
>         Attachments: Screen Shot 2021-06-24 at 3.56.33 PM.png
>
>
> This is a relatively minor issue, but I did spot HRegion.getStores() popping 
> up in my profiler.
> Checking the code, I realized that HRegion.getStores() allocates a new array 
> list in it, converting the Collection<> to List<>. But it also makes it an O( 
> n ) in space and time complexity.
> This conversion appears mostly unnecessary, because we only iterate the 
> stores in production code, and so the new ArrayList object is thrown away 
> immediately. Only in a number of test code where we index into the stores.



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