What causes "Failed to load pool ticks: {e}" in nautechsystems/nautilus_trader?

Check Postgres connectivity and credentials (DATABASE_URL) with psql or a simple health query

nautechsystems/nautilus_trader · error · anyhow::Error

Failed to load pool ticks: {e}

Error message

Failed to load pool ticks: {e}

What it means

This error wraps any database failure that occurs while loading pool tick rows from the Postgres cache via sqlx `fetch_all`. The library throws it to convert the underlying sqlx::Error into an anyhow error with context about which operation (pool ticks load) failed. It indicates the SELECT for pool ticks at a given snapshot block/transaction/log index did not complete.

Source

Thrown at crates/adapters/blockchain/src/cache/database.rs:2749

                tick_value, liquidity_gross::TEXT, liquidity_net::TEXT,
                fee_growth_outside_0::TEXT, fee_growth_outside_1::TEXT, initialized,
                last_updated_block
            FROM pool_tick
            WHERE chain_id = $1
            AND pool_identifier = $2
            AND snapshot_block = $3
            AND snapshot_transaction_index = $4
            AND snapshot_log_index = $5
            ",
        )
        .bind(chain_id as i32)
        .bind(pool_identifier.as_ref())
        .bind(snapshot_block as i64)
        .bind(snapshot_transaction_index as i32)
        .bind(snapshot_log_index as i32)
        .fetch_all(&self.pool)
        .await
        .map_err(|e| anyhow::anyhow!("Failed to load pool ticks: {e}"))?;

        rows.iter()
            .map(|row| {
                let tick = PoolTick::new(
                    row.get("tick_value"),
                    row.get::<String, _>("liquidity_gross").parse()?,
                    row.get::<String, _>("liquidity_net").parse()?,
                    row.get::<String, _>("fee_growth_outside_0").parse()?,
                    row.get::<String, _>("fee_growth_outside_1").parse()?,
                    row.get("initialized"),
                    u64::try_from(row.get::<i64, _>("last_updated_block"))
                        .with_context(|| "Pool tick last updated block is negative")?,
                );
                Ok(tick)
            })
            .collect()
    }

View on GitHub (pinned to 18893faf8b)

Solutions

Check Postgres connectivity and credentials (DATABASE_URL) with psql or a simple health query
Verify the pool ticks table exists and migrations have run; run the schema setup/migration code path
Log the inner error `{e}` to identify the exact sqlx failure (type mismatch vs connection)
Confirm bound types (i64 block, i32 indexes) match the column types
Retry the operation if the failure was a transient connection issue

Example fix

// before
.map_err(|e| anyhow::anyhow!("Failed to load pool ticks: {e}"))?
// after
.map_err(|e| {
    tracing::error!(error = %e, "pool ticks load failed");
    anyhow::anyhow!("Failed to load pool ticks: {e}")
})?

Defensive patterns

Strategy: try-catch

Validate before calling

let ok = sqlx::query("SELECT 1 FROM pool_ticks LIMIT 1").fetch_optional(&pool).await.is_ok();
if !ok { anyhow::bail!("pool_ticks table unavailable"); }

Try / catch

match load_pool_ticks(...).await {
    Ok(ticks) => ticks,
    Err(e) => { tracing::error!(error = %e, "pool ticks load failed"); return Err(e); }
}

Prevention

Run schema migrations at startup before any data loads
Health-check the DB connection before starting cache loads
Match bind parameter types to column types exactly

When it happens

Trigger: Calling the pool ticks loader when the Postgres pool is unreachable, the pool ticks table or queried columns do not exist (schema mismatch/migration not applied), bind parameters have types incompatible with the columns (e.g. i64/i32 casting), or a query timeout/cancellation occurs.

Common situations: Connecting to a database created by an older schema version without migrations; wrong DATABASE_URL pointing to an empty database; network/credential issues in containerized deployments; Postgres restart during query.

Understand the failure class

Background: Database query failed: Internal Server Error 500s wrapping SQL, Prisma, and connection failures — what to check first — this error's family across 16 libraries.

Related errors

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/ad1034bf3043a949. Report an issue: GitHub.