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https://issues.apache.org/jira/browse/HBASE-5056?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13445635#comment-13445635
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stack commented on HBASE-5056:
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@Chris I don't think so.  When I look at attached profiler output, it looks 
like the NullInstance is allocated in HbaseObjectWritable.  It might be gone in 
trunk because we should be by-passing HbaseObjectWritable now we are pb all the 
time but would have to check in profiler again (Not sure how the hfile2 relates 
after this much time has passed).
                
> [performance] On upload, 4% of memory allocations are NullInstance
> ------------------------------------------------------------------
>
>                 Key: HBASE-5056
>                 URL: https://issues.apache.org/jira/browse/HBASE-5056
>             Project: HBase
>          Issue Type: Improvement
>          Components: performance
>            Reporter: stack
>              Labels: noob
>         Attachments: NullInstanceHotSpotMemAllocation.html
>
>
> Profiling a PE upload, I see that 4% of memory allocations are instances of 
> NullInstance (caveat profiler's give distorted view of running app as does PE 
> when it comes to real-world workloads).  See attached profiler output.  Looks 
> like we could save a bunch on object creation if we had our own 
> WritableFactories instance that treated stuff like NullInstance special 
> creating a Singleton NullInstance per declared class type returning these 
> instead of creating new ones.

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