Method build

nodedb/src/engine/timeseries/sparse_index/index.rs:33–83

Build a sparse index from raw column data at flush time. Scans the column data in blocks of `block_size` rows, computing per-block timestamp ranges and per-column min/max statistics.

(
        columns: &[ColumnData],
        schema: &ColumnarSchema,
        row_count: u64,
        block_size: usize,
    )

    /// Scans the column data in blocks of `block_size` rows, computing
    /// per-block timestamp ranges and per-column min/max statistics.
    pub fn build(
        columns: &[ColumnData],
        schema: &ColumnarSchema,
        row_count: u64,
        block_size: usize,
    ) -> Self {
        let block_size = block_size.max(64); // minimum 64 rows per block
        let total_rows = row_count as usize;
        let block_count = if total_rows == 0 {
            0
        } else {
            total_rows.div_ceil(block_size)
        };

        let column_names: Vec<String> = schema.columns.iter().map(|(n, _)| n.clone()).collect();
        let ts_idx = schema.timestamp_idx;

        let mut blocks = Vec::with_capacity(block_count);

        for block_idx in 0..block_count {
            let row_start = block_idx * block_size;
            let row_end = (row_start + block_size).min(total_rows);
            let count = row_end - row_start;

            let (min_ts, max_ts) = if ts_idx < columns.len() {
                compute_ts_range(&columns[ts_idx], row_start, row_end)
            } else {
                (i64::MIN, i64::MAX)
            };

            let column_stats: Vec<BlockColumnStats> = columns
                .iter()
                .zip(schema.columns.iter())
                .map(|(col, (_, col_type))| compute_block_stats(col, *col_type, row_start, row_end))
                .collect();

            blocks.push(BlockEntry {
                row_offset: row_start as u32,
                row_count: count as u32,
                min_ts,
                max_ts,
                column_stats,
            });
        }

        Self {
            block_size: block_size as u32,
            column_names,
            blocks,
        }
    }

    // -- Query methods --