acking-you opened a new pull request, #16930:
URL: https://github.com/apache/datafusion/pull/16930
## Which issue does this PR close?
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- Closes #16928.
## Rationale for this change
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## What changes are included in this PR?
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## Are these changes tested?
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## Are there any user-facing changes?
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## Some thoughts
In current computing frameworks, all computation results are in the form of
immutable shared ownership, which leads to many situations where new buffers
have to be created instead of reusing existing ones.
For example, in the case of early exit optimization, it should be possible
to reuse and modify `lhs` to return the result.
However, doing so under the current framework would lead to memory safety
issues. For instance, the `evaluate` implementation of the Column expression
reuses the original `Arc` to obtain the result instead of creating a new one,
while in other cases a new structure is created (which can be safely modified).
If there were a way to internally indicate whether the current result is
newly created or reuses an `Arc`, and if we could design a mutable API for this
scenario, it might be possible to reduce unnecessary copies in many computation
processes across DataFusion.
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