imply debug for CacheManager

datafusion/core/src/datasource/listing/table.rs

@@ -992,10 +992,6 @@ mod tests {
     use arrow::record_batch::RecordBatch;
     use datafusion_common::assert_contains;
     use datafusion_common::GetExt;
-    use datafusion_execution::cache::cache_manager::CacheManagerConfig;
-    use datafusion_execution::cache::cache_unit;
-    use datafusion_execution::cache::cache_unit::DefaultFileStatisticsCache;
-    use datafusion_execution::runtime_env::{RuntimeConfig, RuntimeEnv};
     use datafusion_expr::LogicalPlanBuilder;
     use rstest::*;
     use std::collections::HashMap;

datafusion/execution/src/cache/cache_manager.rs

@@ -19,6 +19,7 @@ use crate::cache::CacheAccessor;
 use datafusion_common::{Result, Statistics};
 use object_store::path::Path;
 use object_store::ObjectMeta;
+use std::fmt::{Debug, Formatter};
 use std::sync::Arc;
 
 /// The cache of listing files statistics.
@@ -28,7 +29,13 @@ use std::sync::Arc;
 pub type FileStatisticsCache =
     Arc<dyn CacheAccessor<Path, Arc<Statistics>, Extra = ObjectMeta>>;
 
-#[derive(Default)]
+impl Debug for dyn CacheAccessor<Path, Arc<Statistics>, Extra = ObjectMeta> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Cache name: {} with length: {}", self.name(), self.len())
+    }
+}
+
+#[derive(Default, Debug)]
 pub struct CacheManager {
     file_statistic_cache: Option<FileStatisticsCache>,
 }

datafusion/execution/src/cache/cache_unit.rs

@@ -89,6 +89,10 @@ impl CacheAccessor<Path, Arc<Statistics>> for DefaultFileStatisticsCache {
     fn clear(&self) {
         self.statistics.clear()
     }
+
+    fn name(&self) -> String {
+        "DefaultFileStatisticsCache".to_string()
+    }
 }
 
 #[cfg(test)]

datafusion/execution/src/cache/mod.rs

@@ -47,4 +47,6 @@ pub trait CacheAccessor<K, V>: Send + Sync {
     }
     /// Removes all entries from the cache.
     fn clear(&self);
+    /// Return the cache name.
+    fn name(&self) -> String;
 }