nautechsystems/nautilus_trader · error

Pool profiler for has processed no events

Error message

Pool profiler for {instrument_id} has processed no events

What it means

Even when a pool profiler exists, it must have processed at least one pool event (`last_processed_event` set) to quote reliably. An initialized flag without any processed events yields no usable cursor/liquidity state, so the swap is rejected.

Solutions

1. Wait until the profiler has processed its first event (poll `last_processed_event`) before submitting swaps
2. Check the pool event stream/WebSocket for stalls and reconnect if no events arrive
3. Re-trigger history/backfill replay so the profiler ingests past events
4. Verify the pool actually emits events (active pool) and the subscription filter targets it

Example fix

// before
submit_order(order); // profiler just created
// after
let profiler = cache.pool_profiler(&id).unwrap();
assert!(profiler.last_processed_event.is_some(), "await first pool event");
submit_order(order);

if let Some(p) = client.cache().pool_profiler(&instrument_id) {
    if p.last_processed_event.is_none() {
        return Err("profiler has no processed events; wait for first pool event".into());
    }
}

fn has_processed_events(p: &PoolProfiler) -> bool {
    p.last_processed_event.is_some()
}

match client.submit_order(order).await {
    Err(e) if e.to_string().contains("has processed no events") => {
        wait_until(|| profiler(&instrument_id).last_processed_event.is_some()).await?;
        client.submit_order(order).await
    }
    r => r,
}

When it happens

Trigger: `prepare_swap()` finds a profiler with `is_initialized == true` but `last_processed_event == None` — the profiler was created but no pool events were processed before the quote attempt.

Common situations: Submitting orders immediately after subscription before the first event arrives; event stream stalled (RPC/websocket drop) after profiler creation; profiler snapshot restored but history replay not yet started.

Understand the failure class

Background: EmptyResultError / "no results found": when an API or scraper succeeds but returns zero rows — this error's family across 9 libraries.

Related errors

• No pool profiler for
• cannot advance an RPC profiler without a snapshot watermark
• Pool profiler for is not initialized
• A recoverable execution for wallet
• Active execution intent

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/08fc50b9872a9678. Report an issue: GitHub.

Appendix: source

Thrown at crates/adapters/blockchain/src/execution/client.rs:1668

            None
        };

        let profiler = self
            .core
            .cache()
            .pool_profiler(&instrument_id)
            .cloned()
            .ok_or_else(|| {
                anyhow::anyhow!(
                    "No pool profiler for {instrument_id}; an active data subscription is required to quote the swap"
                )
            })?;

        if !profiler.is_initialized {
            anyhow::bail!("Pool profiler for {instrument_id} is not initialized");
        }
        let profiler_position = profiler.last_processed_event.clone().ok_or_else(|| {
            anyhow::anyhow!("Pool profiler for {instrument_id} has processed no events")
        })?;

        let zero_for_one = token_in == pool.token0.address;
        let (amount_in, quoted_amount_out) = match order.order_side() {
            OrderSide::Sell => {
                let quote = profiler
                    .swap_exact_in(base_amount, zero_for_one, None)
                    .map_err(|e| anyhow::anyhow!("Swap quote failed for {instrument_id}: {e}"))?;
                let amount_filled = if zero_for_one {
                    quote.amount0
                } else {
                    quote.amount1
                };

                if amount_filled != I256::from(base_amount) {
                    anyhow::bail!(
                        "Local quote for {instrument_id} filled {amount_filled} of the {base_amount} order amount; pool liquidity cannot fill the order"
                    );

View on GitHub (pinned to 18893faf8b)