Method split

datafusion/datasource/src/memory.rs:627–656

Split [`RePartition`] into 2 pieces, consuming self. Returns only 1 partition if cannot be split further.

(self)

    ///
    /// Returns only 1 partition if cannot be split further.
    fn split(self) -> Vec<Self> {
        if self.batches.len() == 1 {
            return vec![self];
        }

        let new_0 = RePartition {
            idx: self.idx, // output ordering
            row_count: 0,
            batches: vec![],
        };
        let new_1 = RePartition {
            idx: self.idx + 1, // output ordering +1
            row_count: 0,
            batches: vec![],
        };
        let split_pt = self.row_count / 2;

        let [new_0, new_1] = self.batches.into_iter().fold(
            [new_0, new_1],
            |[mut new0, mut new1], batch| {
                if new0.row_count < split_pt {
                    new0.add_batch(batch);
                } else {
                    new1.add_batch(batch);
                }
                [new0, new1]
            },
        );
        vec![new_0, new_1]
    }

    fn add_batch(&mut self, batch: RecordBatch) {
        self.row_count += batch.num_rows();