nautechsystems/nautilus_trader · error · anyhow::Error

AX open-orders returned an empty page before offset {offset}

Error message

AX open-orders returned an empty page before offset {offset} reached total {total_count}

What it means

During offset pagination, a mid-stream empty page before reaching total_count means rows are missing: the server advertised more orders than it will ever return at the current offsets. The client fails fast rather than silently returning fewer orders than the venue promised.

Source

Thrown at crates/adapters/architect_ax/src/http/client.rs:2043

                response.limit
            );
            let next_offset = offset
                .checked_add(page_len)
                .context("AX open-orders offset overflow")?;
            anyhow::ensure!(
                next_offset <= total_count,
                "AX open-orders page exceeds total_count: next offset {next_offset}, total {total_count}"
            );

            if total_count == 0 {
                anyhow::ensure!(
                    response.orders.is_empty(),
                    "AX open-orders returned rows with total_count zero"
                );
                break;
            }

            anyhow::ensure!(
                !response.orders.is_empty(),
                "AX open-orders returned an empty page before offset {offset} reached total {total_count}"
            );

            for order in response.orders {
                anyhow::ensure!(
                    seen_order_ids.insert(order.oid.clone()),
                    "AX open-orders pagination returned duplicate order ID {}",
                    order.oid
                );
                orders.push(order);
            }

            if next_offset == total_count {
                break;
            }

            offset = next_offset;

View on GitHub (pinned to 18893faf8b)

Solutions

1. Retry the full pagination from offset 0
2. Re-check whether the orders were legitimately canceled mid-poll (expected churn, not a bug)
3. Verify the adapter's offset/limit parameters against current AX API docs
4. Increase page size to reduce the number of pages and the window for churn

if offset < total_count && page.orders.is_empty() {
    return Err(anyhow!("empty page at offset {offset}, total {total_count}"));
}

match result {
    Err(e) if e.to_string().contains("empty page before offset") => restart_pagination(),
    Err(e) => return Err(e),
    Ok(orders) => use(orders),
}

When it happens

Trigger: Server returns an empty orders array while offset < total_count, e.g. rows were removed server-side after the total was computed, or a page boundary bug skips rows.

Common situations: Orders canceled during pagination; venue soft-deleting rows without adjusting totals; API pagination endpoint regression.

Understand the failure class

Background: "invalid response format", "malformed payload", "missing data field": when an API returns 200 but the response shape is wrong — this error's family across 23 libraries.

Related errors

• AX open-orders total_count changed during pagination: expect
• AX open-orders page length {page_len} exceeds applied limit
• AX open-orders page exceeds total_count: next offset {next_o
• AX open-orders returned rows with total_count zero
• AX open-orders pagination returned duplicate order ID {}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/9687430e00451492. Report an issue: GitHub.