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new 75538c8c5e doc: More comments to `concat_batches` (#10178)
75538c8c5e is described below
commit 75538c8c5e69d192a191c0dab4bf78ba148b6e98
Author: Yongting You <[email protected]>
AuthorDate: Mon Jun 22 23:06:59 2026 +0800
doc: More comments to `concat_batches` (#10178)
# Which issue does this PR close?
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# Rationale for this change
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This adds more documentation for `concat_batches()`. Both points have
caused bugs or inefficiencies in DataFusion, so I think they are worth
documenting, even if the `StringArray` offset issue is slightly outside
the scope of this function.
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---
arrow-select/src/concat.rs | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arrow-select/src/concat.rs b/arrow-select/src/concat.rs
index bb85d7035a..88faf98872 100644
--- a/arrow-select/src/concat.rs
+++ b/arrow-select/src/concat.rs
@@ -593,6 +593,16 @@ fn concat_fallback(arrays: &[&dyn Array], capacity:
Capacities) -> Result<ArrayR
/// The output batch has the specified `schemas`; The schema of the
/// input are ignored.
///
+/// # Notes
+///
+/// - Callers should budget for peak memory use to approach 2x the input
+/// size, as the input batches and output arrays co-exist during
construction.
+/// - Arrays with `i32` offsets, such as `StringArray` and `BinaryArray`, only
+/// support up to ~2GiB of payloads. Concatenating large arrays of these
types
+/// can cause offset overflows.
+///
+/// # Errors
+///
/// Returns an error if the types of underlying arrays are different.
pub fn concat_batches<'a>(
schema: &SchemaRef,
