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phraktle

opened on Nov 30, 2020

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Hi,

I'm interested in decoding integers from an off-heap direct buffer, but I currently see no way of doing this without copying them to the heap. Is there a suggested method of doing this? Is there a fundamental (eg. performance) reason why this is not implemented or is it just to avoid the complexity?

Thanks,
Viktor

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1. lemire commented on Nov 30, 2020

   

   lemire

   on Nov 30, 2020

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    Is there a fundamental (eg. performance) reason why this is not implemented or is it just to avoid the complexity?

   Does the following help?

   Java Buffer types versus native arrays: which is faster?
   https://lemire.me/blog/2020/11/30/java-buffer-types-versus-native-arrays-which-is-faster/
2. lemire commented on Dec 1, 2020

   

   lemire

   on Dec 1, 2020

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   If someone would like to propose pull requests leveraging Buffer types, I would be eager to review it. However, one has to be mindful of the performance considerations... and it is not trivial...

   The complexity is not much of an issue. One could almost entirely automate the conversion process with a script.

   However, it would be easy for a user to get bad performance, through no fault of their own, by misusing the Buffer types. So one would need to add good documentation/guidance.
3. huang-jesse commented on Nov 1, 2023

   

   huang-jesse

   on Nov 1, 2023

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   Good insight. I recently implemented a TSDB using DirectByteBuffer to hold int data, because I didn't want a transfer station (and wanted to save memory), so I did not use native arrays .

   However, your opinion makes sense. native arrays may provide better performance compared to ByteBuffer.

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