Method repartition_file_groups

datafusion/datasource/src/file_groups.rs:186–200

Repartition input files according to the settings on this [`FileGroupPartitioner`]. If no repartitioning is needed or possible, return `None`.

(
        &self,
        file_groups: &[FileGroup],
    )

    ///
    /// If no repartitioning is needed or possible, return `None`.
    pub fn repartition_file_groups(
        &self,
        file_groups: &[FileGroup],
    ) -> Option<Vec<FileGroup>> {
        if file_groups.is_empty() {
            return None;
        }

        //  special case when order must be preserved
        if self.preserve_order_within_groups {
            self.repartition_preserving_order(file_groups)
        } else {
            self.repartition_evenly_by_size(file_groups)
        }
    }

    /// Evenly repartition files across partitions by size, ignoring any
    /// existing grouping / ordering