feat: support stateless physical plans

datafusion/datasource-parquet/src/opener.rs

@@ -1303,10 +1303,8 @@ mod test {
     }
 
     fn make_dynamic_expr(expr: Arc<dyn PhysicalExpr>) -> Arc<dyn PhysicalExpr> {
-        Arc::new(DynamicFilterPhysicalExpr::new(
-            expr.children().into_iter().map(Arc::clone).collect(),
-            expr,
-        ))
+        let children = expr.children().into_iter().map(Arc::clone).collect();
+        Arc::new(DynamicFilterPhysicalExpr::new(expr, children))
     }
 
     #[tokio::test]

datafusion/execution/src/metrics/mod.rs

@@ -89,9 +89,9 @@ pub struct Metric {
 ///   will be shown.
 /// - When set to `summary`, only metrics with type `MetricType::Summary` are shown.
 ///
-/// # Difference from `EXPLAIN ANALYZE VERBOSE`:  
-/// The `VERBOSE` keyword controls whether per-partition metrics are shown (when specified),  
-/// or aggregated metrics are displayed (when omitted).  
+/// # Difference from `EXPLAIN ANALYZE VERBOSE`:
+/// The `VERBOSE` keyword controls whether per-partition metrics are shown (when specified),
+/// or aggregated metrics are displayed (when omitted).
 /// In contrast, the `analyze_level` configuration determines which categories or
 /// levels of metrics are displayed.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -213,6 +213,16 @@ impl MetricsSet {
         Default::default()
     }
 
+    /// Return a number of metrics.
+    pub fn len(&self) -> usize {
+        self.metrics.len()
+    }
+
+    /// Check if the set is empty.
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     /// Add the specified metric
     pub fn push(&mut self, metric: Arc<Metric>) {
         self.metrics.push(metric)