Add metadata_load_time metric

datafusion/core/src/datasource/physical_plan/parquet/metrics.rs

@@ -55,6 +55,8 @@ pub struct ParquetFileMetrics {
     pub page_index_rows_matched: Count,
     /// Total time spent evaluating parquet page index filters
     pub page_index_eval_time: Time,
+    /// Total time spent reading and parsing metadata from the footer
+    pub metadata_load_time: Time,
 }
 
 impl ParquetFileMetrics {
@@ -116,6 +118,10 @@ impl ParquetFileMetrics {
             .with_new_label("filename", filename.to_string())
             .subset_time("page_index_eval_time", partition);
 
+        let metadata_load_time = MetricBuilder::new(metrics)
+            .with_new_label("filename", filename.to_string())
+            .subset_time("metadata_load_time", partition);
+
         Self {
             predicate_evaluation_errors,
             row_groups_matched_bloom_filter,
@@ -131,6 +137,7 @@ impl ParquetFileMetrics {
             statistics_eval_time,
             bloom_filter_eval_time,
             page_index_eval_time,
+            metadata_load_time,
         }
     }
 }

datafusion/core/src/datasource/physical_plan/parquet/opener.rs

@@ -118,6 +118,7 @@ impl FileOpener for ParquetOpener {
         Ok(Box::pin(async move {
             let options = ArrowReaderOptions::new().with_page_index(enable_page_index);
 
+            let mut metadata_timer = file_metrics.metadata_load_time.timer();
             let metadata =
                 ArrowReaderMetadata::load_async(&mut reader, options.clone()).await?;
             let mut schema = metadata.schema().clone();
@@ -133,6 +134,8 @@ impl FileOpener for ParquetOpener {
             let metadata =
                 ArrowReaderMetadata::try_new(metadata.metadata().clone(), options)?;
 
+            metadata_timer.stop();
+
             let mut builder =
                 ParquetRecordBatchStreamBuilder::new_with_metadata(reader, metadata);