Thank you @westhide

Should we remove the batch_size from JSON source too?

datafusion/datafusion/datasource-json/src/source.rs

Line 254 in dd9c3a8

batch_size: Option<usize>,

Can we add context: Arc<TaskContext> to the create_file_opener args? The default batch_size is from context.session_config().batch_size(). If we remove batch_size property in JsonSource, we need to get the default value by context

pub trait FileSource: Send + Sync {
    /// Creates a `dyn FileOpener` based on given parameters
    fn create_file_opener(
        &self,
        object_store: Arc<dyn ObjectStore>,
        base_config: &FileScanConfig,
        partition: usize,
    ) -> Arc<dyn FileOpener>;
    // ...
}