Skip to content

minor: More comments to read_spill_as_stream #21713

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
2010YOUY01 merged 2 commits into from
Apr 20, 2026
Merged

minor: More comments to read_spill_as_stream #21713

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
a46cfde
comment to `read_spill_as_stream`
2010YOUY01 Apr 18, 2026
8a89c0c
review: more comment
2010YOUY01 Apr 19, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 16 additions & 3 deletions datafusion/physical-plan/src/spill/spill_manager.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -160,9 +160,22 @@ impl SpillManager {
Ok(file.map(|f| (f, max_record_batch_size)))
}

/// Reads a spill file as a stream. The file must be created by the current `SpillManager`.
/// This method will generate output in FIFO order: the batch appended first
/// will be read first.
/// Reads a spill file as a stream. The file must be created by the current
Copy link
Copy Markdown
Contributor

@comphead comphead Apr 18, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

what would happen if file created by another SpillManager? would the file be ignored or crash?

Copy link
Copy Markdown
Contributor Author

@2010YOUY01 2010YOUY01 Apr 19, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I looked at the code—it appears to succeed silently, and error would be propagated to the stream consumer due to a schema mismatch.
I’ve updated the comment to indicate this may lead to undefined behavior.
We could be more defensive here; I’ll send a follow-up patch to make it fail fast.

/// `SpillManager`; otherwise behavior is undefined.
///
/// Output is produced in FIFO order: the batch appended first is read first.
///
/// # Arg `max_record_batch_memory`
///
/// Most callers should pass `None`. This is mainly useful for the
/// memory-limited sort-preserving merge path.
///
/// When provided, this value is used only as a validation hint. If a
/// decoded batch exceeds this threshold, a debug-level log message is
/// emitted.
///
/// That path uses the maximum spilled batch size to conservatively estimate
/// the merge degree when merging multiple sorted runs.
pub fn read_spill_as_stream(
&self,
spill_file_path: RefCountedTempFile,
Expand Down
Loading