(datafusion) branch db/cache-cores created (now c4c745e53e)

[bl...@apache.org]

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blaginin pushed a change to branch db/cache-cores
in repository https://gitbox.apache.org/repos/asf/datafusion.git


      at c4c745e53e cached `get_available_parallelism`

This branch includes the following new commits:

     new c4c745e53e cached `get_available_parallelism`

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(datafusion) 01/01: cached `get_available_parallelism`

[bl...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

blaginin pushed a commit to branch db/cache-cores
in repository https://gitbox.apache.org/repos/asf/datafusion.git

commit c4c745e53ebfac6d87f492bf005578b2a36fa696
Author: blaginin <gi...@blaginin.me>
AuthorDate: Fri Mar 20 19:50:33 2026 +0000

    cached `get_available_parallelism`
---
 datafusion/common/src/utils/mod.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/datafusion/common/src/utils/mod.rs b/datafusion/common/src/utils/mod.rs
index 075a189c37..9752574002 100644
--- a/datafusion/common/src/utils/mod.rs
+++ b/datafusion/common/src/utils/mod.rs
@@ -40,7 +40,7 @@ use std::cmp::{Ordering, min};
 use std::collections::HashSet;
 use std::num::NonZero;
 use std::ops::Range;
-use std::sync::Arc;
+use std::sync::{Arc, LazyLock};
 use std::thread::available_parallelism;
 
 /// Applies an optional projection to a [`SchemaRef`], returning the
@@ -923,10 +923,15 @@ pub fn combine_limit(
 ///
 /// This is a wrapper around `std::thread::available_parallelism`, providing a default value
 /// of `1` if the system's parallelism cannot be determined.
+///
+/// The result is cached after the first call.
 pub fn get_available_parallelism() -> usize {
-    available_parallelism()
-        .unwrap_or(NonZero::new(1).expect("literal value `1` shouldn't be zero"))
-        .get()
+    static PARALLELISM: LazyLock<usize> = LazyLock::new(|| {
+        available_parallelism()
+            .unwrap_or(NonZero::new(1).expect("literal value `1` shouldn't be zero"))
+            .get()
+    });
+    *PARALLELISM
 }
 
 /// Converts a collection of function arguments into a fixed-size array of length N


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