Function merge_slice_rows

nodedb-cluster/src/distributed_array/merge.rs:109–129

Merge row batches from multiple shards into one result set. Rows are concatenated in shard-arrival order (order-independent for an unsorted slice). If `coordinator_limit > 0` the merged list is truncated to at most `coordinator_limit` rows after concatenation — this is the final cut-off after shards have already applied their own per-shard limit via `ArrayShardSliceReq::limit`. Pass `coordinator

(
    shard_resps: &[ArrayShardSliceResp],
    coordinator_limit: u32,
)

///
/// Pass `coordinator_limit = 0` to return all rows without truncation.
pub fn merge_slice_rows(
    shard_resps: &[ArrayShardSliceResp],
    coordinator_limit: u32,
) -> Vec<Vec<u8>> {
    let total: usize = shard_resps.iter().map(|r| r.rows_msgpack.len()).sum();
    let cap = if coordinator_limit > 0 {
        total.min(coordinator_limit as usize)
    } else {
        total
    };
    let mut merged = Vec::with_capacity(cap);
    'outer: for resp in shard_resps {
        for row in &resp.rows_msgpack {
            if coordinator_limit > 0 && merged.len() >= coordinator_limit as usize {
                break 'outer;
            }
            merged.push(row.clone());
        }
    }
    merged
}

/// Merge per-shard partial aggregates into one result per group-by key.
///