nuno-faria opened a new pull request, #17622:
URL: https://github.com/apache/datafusion/pull/17622
## Which issue does this PR close?
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- Closes #17597.
## Rationale for this change
The original code was referencing a record batch for each line in the limit,
which was causing the `arrow_select::interleave_record_batch` to allocate
vectors with billions of elements. For example, if we had 32 batches and `LIMIT
50000`, those 32 batches would be referenced 50k times. The new version uses
only one reference per existing batch, limiting the memory used as well as
improving the execution time:
```sql
> select *
from lineitem
order by l_comment;
-- Elapsed 1.804 seconds.
-- would OOM before
> select *
from lineitem
order by l_comment
limit 50000;
-- Elapsed 0.625 seconds.
```
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## What changes are included in this PR?
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sometimes worth providing a summary of the individual changes in this PR.
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- Updated the way the record batches and indices are created in
`topk/mod.rs`.
## Are these changes tested?
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2. Serve as another way to document the expected behavior of the code
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Yes.
## Are there any user-facing changes?
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No.
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