comment: add test comment

tests/scan.rs

@@ -593,6 +593,11 @@ async fn test_prepare_stmt_execute(#[future(awt)] s3: S3, mut conn: PgConnection
     Ok(())
 }
 
+// Note: PostgreSQL will replan the query when certain catalog changes occur,
+// such as changes to the search path or when a table is deleted.
+// In contrast, DuckDB does not replan when the search path is changed.
+// If there are two foreign tables in different schemas and the prepared statements do not specify the schemas,
+// it may lead to ambiguity or errors when referencing the tables.
 #[rstest]
 async fn test_prepare_search_path(mut conn: PgConnection, tempdir: TempDir) -> Result<()> {
     let stored_batch = primitive_record_batch()?;
@@ -612,6 +617,8 @@ async fn test_prepare_search_path(mut conn: PgConnection, tempdir: TempDir) -> R
     writer.write(&stored_batch_less)?;
     writer.close()?;
 
+    // In this example, we create two tables with identical structures and names, but in different schemas.
+    // We expect that when the search path is changed, the correct table (the one in the current schema) will be referenced in DuckDB.
     "CREATE SCHEMA tpch1".execute(&mut conn);
     "CREATE SCHEMA tpch2".execute(&mut conn);