fix: stack overflow when loading large equality deletes

crates/iceberg/src/arrow/caching_delete_file_loader.rs

@@ -330,7 +330,7 @@ impl CachingDeleteFileLoader {
         mut stream: ArrowRecordBatchStream,
         equality_ids: HashSet<i32>,
     ) -> Result<Predicate> {
-        let mut result_predicate = AlwaysTrue;
+        let mut row_predicates = Vec::new();
         let mut batch_schema_iceberg: Option<Schema> = None;
         let accessor = EqDelRecordBatchPartnerAccessor;
 
@@ -374,10 +374,29 @@ impl CachingDeleteFileLoader {
                         row_predicate = row_predicate.and(cell_predicate)
                     }
                 }
-                result_predicate = result_predicate.and(row_predicate.not());
+                row_predicates.push(row_predicate.not().rewrite_not());
             }
         }
-        Ok(result_predicate.rewrite_not())
+
+        // All row predicates are combined to a single predicate by creating a balanced binary tree.
+        // Using a simple fold would result in a deeply nested predicate that can cause a stack overflow.
+        while row_predicates.len() > 1 {
+            let mut next_level = Vec::with_capacity(row_predicates.len().div_ceil(2));
+            let mut iter = row_predicates.into_iter();
+            while let Some(p1) = iter.next() {
+                if let Some(p2) = iter.next() {
+                    next_level.push(p1.and(p2));
+                } else {
+                    next_level.push(p1);
+                }
+            }
+            row_predicates = next_level;
+        }
+
+        match row_predicates.pop() {
+            Some(p) => Ok(p),
+            None => Ok(AlwaysTrue),
+        }
     }
 }
 
@@ -912,4 +931,51 @@ mod tests {
             result.err()
         );
     }
+
+    #[tokio::test]
+    async fn test_large_equality_delete_batch_stack_overflow() {
+        let tmp_dir = TempDir::new().unwrap();
+        let table_location = tmp_dir.path().as_os_str().to_str().unwrap();
+        let file_io = FileIO::from_path(table_location).unwrap().build().unwrap();
+
+        // Create a large batch of equality deletes
+        let num_rows = 20_000;
+        let col_y_vals: Vec<i64> = (0..num_rows).collect();
+        let col_y = Arc::new(Int64Array::from(col_y_vals)) as ArrayRef;
+
+        let schema = Arc::new(arrow_schema::Schema::new(vec![
+            Field::new("y", arrow_schema::DataType::Int64, false).with_metadata(HashMap::from([(
+                PARQUET_FIELD_ID_META_KEY.to_string(),
+                "2".to_string(),
+            )])),
+        ]));
+
+        let record_batch = RecordBatch::try_new(schema.clone(), vec![col_y]).unwrap();
+
+        // Write to file
+        let path = format!("{}/large-eq-deletes.parquet", &table_location);
+        let file = File::create(&path).unwrap();
+        let props = WriterProperties::builder()
+            .set_compression(Compression::SNAPPY)
+            .build();
+        let mut writer = ArrowWriter::try_new(file, schema, Some(props)).unwrap();
+        writer.write(&record_batch).unwrap();
+        writer.close().unwrap();
+
+        let basic_delete_file_loader = BasicDeleteFileLoader::new(file_io.clone());
+        let record_batch_stream = basic_delete_file_loader
+            .parquet_to_batch_stream(&path)
+            .await
+            .expect("could not get batch stream");
+
+        let eq_ids = HashSet::from_iter(vec![2]);
+
+        let result = CachingDeleteFileLoader::parse_equality_deletes_record_batch_stream(
+            record_batch_stream,
+            eq_ids,
+        )
+        .await;
+
+        assert!(result.is_ok());
+    }
 }