(datafusion) branch main updated: Improve ergonomics for ExecutionPlanMetricsSet and MetricsSet (#21762)

[gi...@apache.org]

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The following commit(s) were added to refs/heads/main by this push:
     new ff844be198 Improve ergonomics for ExecutionPlanMetricsSet and MetricsSet (#21762)
ff844be198 is described below

commit ff844be198821863f013c47d527cf879ba783636
Author: Gabriel <45...@users.noreply.github.com>
AuthorDate: Wed Apr 22 15:13:48 2026 +0200

    Improve ergonomics for ExecutionPlanMetricsSet and MetricsSet (#21762)
    
    ## 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.
    -->
    
    - None
    
    ## 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.
    -->
    
    Sometimes, when an `ExecutionPlan` implementation is complex, different
    metrics are collected from different structs that compose the whole
    execution plan.
    
    These metrics need to eventually be served from the single entrypoint
    `ExecutionPlan::metrics()` or `DataSource::metrics()`, and the current
    api does not have good methods for merging several
    `ExecutionPlanMetricsSet` coming from different sources into a single
    one.
    
    ## 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.
    -->
    
    Add some basic conversion and iteration methods for `MetricsSet` and
    `ExecutionPlanMetricsSet`, in order to improve ergonomics around these
    structs.
    
    ## 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)?
    -->
    
    This is purely just basic std trait implementations and method exposure,
    so as long as the code compiles, I don't think it needs further tests.
    
    ## Are there any user-facing changes?
    
    People will see some more available methods in the `MetricsSet` and
    `ExecutionPlanMetricsSet` structs for ergonomics.
    
    <!--
    If there are user-facing changes then we may require documentation to be
    updated before approving the PR.
    -->
    
    <!--
    If there are any breaking changes to public APIs, please add the `api
    change` label.
    -->
---
 datafusion/physical-expr-common/src/metrics/mod.rs | 87 ++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/datafusion/physical-expr-common/src/metrics/mod.rs b/datafusion/physical-expr-common/src/metrics/mod.rs
index 8d877713ca..285e856635 100644
--- a/datafusion/physical-expr-common/src/metrics/mod.rs
+++ b/datafusion/physical-expr-common/src/metrics/mod.rs
@@ -30,6 +30,7 @@ use std::{
     borrow::Cow,
     fmt::{self, Debug, Display},
     sync::Arc,
+    vec::IntoIter,
 };
 
 // public exports
@@ -432,6 +433,38 @@ impl Display for MetricsSet {
     }
 }
 
+impl IntoIterator for MetricsSet {
+    type Item = Arc<Metric>;
+    type IntoIter = IntoIter<Self::Item>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.metrics.into_iter()
+    }
+}
+
+impl<'a> IntoIterator for &'a MetricsSet {
+    type Item = &'a Arc<Metric>;
+    type IntoIter = std::slice::Iter<'a, Arc<Metric>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.metrics.iter()
+    }
+}
+
+impl Extend<Arc<Metric>> for MetricsSet {
+    fn extend<I: IntoIterator<Item = Arc<Metric>>>(&mut self, iter: I) {
+        self.metrics.extend(iter);
+    }
+}
+
+impl FromIterator<Arc<Metric>> for MetricsSet {
+    fn from_iter<T: IntoIterator<Item = Arc<Metric>>>(iter: T) -> Self {
+        Self {
+            metrics: iter.into_iter().collect(),
+        }
+    }
+}
+
 /// A set of [`Metric`]s for an individual operator.
 ///
 /// This structure is intended as a convenience for execution plan
@@ -465,6 +498,14 @@ impl ExecutionPlanMetricsSet {
     }
 }
 
+impl From<MetricsSet> for ExecutionPlanMetricsSet {
+    fn from(metrics: MetricsSet) -> Self {
+        Self {
+            inner: Arc::new(Mutex::new(metrics)),
+        }
+    }
+}
+
 /// `name=value` pairs identifying a metric. This concept is called various things
 /// in various different systems:
 ///
@@ -752,6 +793,52 @@ mod tests {
         };
     }
 
+    #[test]
+    fn test_extend() {
+        let mut metrics = MetricsSet::new();
+        let m1 = Arc::new(Metric::new(MetricValue::OutputRows(Count::new()), None));
+        let m2 = Arc::new(Metric::new(MetricValue::SpillCount(Count::new()), None));
+
+        metrics.extend([Arc::clone(&m1), Arc::clone(&m2)]);
+        assert_eq!(metrics.iter().count(), 2);
+
+        let m3 = Arc::new(Metric::new(MetricValue::SpilledBytes(Count::new()), None));
+        metrics.extend(std::iter::once(Arc::clone(&m3)));
+        assert_eq!(metrics.iter().count(), 3);
+    }
+
+    #[test]
+    fn test_collect() {
+        let m1 = Arc::new(Metric::new(MetricValue::OutputRows(Count::new()), None));
+        let m2 = Arc::new(Metric::new(MetricValue::SpillCount(Count::new()), None));
+
+        let metrics: MetricsSet =
+            vec![Arc::clone(&m1), Arc::clone(&m2)].into_iter().collect();
+        assert_eq!(metrics.iter().count(), 2);
+
+        let empty: MetricsSet = std::iter::empty().collect();
+        assert_eq!(empty.iter().count(), 0);
+    }
+
+    #[test]
+    fn test_into_iterator_by_ref() {
+        let mut metrics = MetricsSet::new();
+        metrics.push(Arc::new(Metric::new(
+            MetricValue::OutputRows(Count::new()),
+            None,
+        )));
+        metrics.push(Arc::new(Metric::new(
+            MetricValue::SpillCount(Count::new()),
+            None,
+        )));
+
+        let mut count = 0;
+        for _m in &metrics {
+            count += 1;
+        }
+        assert_eq!(count, 2);
+    }
+
     #[test]
     fn test_sorted_for_display() {
         let metrics = ExecutionPlanMetricsSet::new();


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