acking-you opened a new pull request, #16930:
URL: https://github.com/apache/datafusion/pull/16930
## Which issue does this PR close?
<!--
We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases. You can
link an issue to this PR using the GitHub syntax. For example `Closes #123`
indicates that this PR will close issue #123.
-->
- Closes #16928.
## Rationale for this change
<!--
Why are you proposing this change? If this is already explained clearly in
the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand your
changes and offer better suggestions for fixes.
-->
## What changes are included in this PR?
<!--
There is no need to duplicate the description in the issue here but it is
sometimes worth providing a summary of the individual changes in this PR.
-->
## Are these changes tested?
<!--
We typically require tests for all PRs in order to:
1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code
If tests are not included in your PR, please explain why (for example, are
they covered by existing tests)?
-->
## Are there any user-facing changes?
<!--
If there are user-facing changes then we may require documentation to be
updated before approving the PR.
-->
No
<!--
If there are any breaking changes to public APIs, please add the `api
change` label.
-->
## 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.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
