better debug logs for xBestIndex

parquet/parquet_table.h

@@ -1,14 +1,17 @@
 #ifndef PARQUET_TABLE_H
 #define PARQUET_TABLE_H
 
+#include <vector>
 #include <string>
 
 class ParquetTable {
+  std::vector<std::string> columnNames;
+
 public:
   ParquetTable(std::string file);
   std::string CreateStatement();
   std::string file;
-
+  std::string columnName(int idx);
 };
 
 #endif