[jira] [Commented] (HIVE-23540) Fix Findbugs Warnings in EncodedColumnBatch

["Gopal Vijayaraghavan (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-23540?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17114567#comment-17114567 ] 

Gopal Vijayaraghavan commented on HIVE-23540:
---------------------------------------------

Not a direct concern, but singleton access seems to hurt LLAP a fair bit.

{code}
-    private List<MemoryBuffer> cacheBuffers;
+    private List<MemoryBuffer> cacheBuffers = Collections.emptyList();
{code}

is the sort of thing which causes false-sharing with multi-threaded access patterns (because a NULL check is zero cost memory access, while a singleton needs to be loaded from corresponding memory zone - near or far).

Was that actually a warning to fix?

> Fix Findbugs Warnings in EncodedColumnBatch
> -------------------------------------------
>
>                 Key: HIVE-23540
>                 URL: https://issues.apache.org/jira/browse/HIVE-23540
>             Project: Hive
>          Issue Type: Improvement
>          Components: storage-api
>            Reporter: David Mollitor
>            Assignee: David Mollitor
>            Priority: Minor
>         Attachments: HIVE-23540.1.patch
>
>




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