nautechsystems/nautilus_trader · error · anyhow::Error

Failed to load pool {pool_identifier}: {e}

Error message

Failed to load pool {pool_identifier}: {e}

What it means

Wraps a failed SELECT of a single pool row by identifier (fetch_optional). Only an SQL-execution failure raises this error; a missing row legitimately returns None and does not error. The pool identifier is interpolated into the message for quick diagnosis.

Source

Thrown at crates/adapters/blockchain/src/cache/database.rs:1386

    ///
    /// # Errors
    ///
    /// Returns an error if the database query fails.
    pub async fn load_pool(
        &self,
        chain: SharedChain,
        dex_id: &str,
        pool_identifier: &PoolIdentifier,
    ) -> anyhow::Result<Option<PoolRow>> {
        sqlx::query_as::<_, PoolRow>(AssertSqlSafe(format!(
            "SELECT {POOL_ROW_COLUMNS} FROM pool WHERE chain_id = $1 AND dex_name = $2 AND pool_identifier = $3"
        )))
        .bind(chain.chain_id as i32)
        .bind(dex_id)
        .bind(pool_identifier.as_ref())
        .fetch_optional(&self.pool)
        .await
        .map_err(|e| anyhow::anyhow!("Failed to load pool {pool_identifier}: {e}"))
    }

    /// Toggles performance optimization settings for sync operations.
    ///
    /// When enabled (true), applies settings for maximum write performance:
    /// - `synchronous_commit` = OFF
    /// - `work_mem` increased for bulk operations
    ///
    /// When disabled (false), restores default safe settings:
    /// - `synchronous_commit` = ON (data safety)
    /// - `work_mem` back to default
    ///
    /// # Errors
    ///
    /// Returns an error if the database operations fail.
    pub async fn toggle_perf_sync_settings(&self, enable: bool) -> anyhow::Result<()> {
        if enable {
            log::debug!("Enabling performance sync settings for bulk operations");

View on GitHub (pinned to 18893faf8b)

Solutions

1. Read the underlying `{e}`; for 'relation does not exist' run pending migrations.
2. Treat None results as expected — only act when the embedded SQL error indicates a real failure.
3. Confirm the identifier format matches the column's stored format (e.g. lowercase address).
4. Check database reachability and retry transient connection errors.

Example fix

// before: error conflated with not-found handling
let row = self.load_pool(chain, dex_id, id).await?;
// after: handle None explicitly, error only on real failures
match self.load_pool(chain, dex_id, id).await {
    Ok(Some(pool)) => analyze(pool),
    Ok(None) => log::warn!("pool {id} not found"),
    Err(e) => return Err(e),
}

// validate the identifier shape before querying
let is_valid_id = |id: &str| !id.is_empty() && id.len() <= 64;
if !is_valid_id(pool_identifier.as_ref()) { return Err(anyhow!("invalid pool identifier")); }

match self.load_pool(chain, dex, id).await {
    Ok(Some(pool)) => Ok(Some(pool)),
    Ok(None) => Ok(None), // not-found is not an error
    Err(e) => Err(anyhow!("pool lookup for {id} failed: {e}")),
}

When it happens

Trigger: Calling the per-pool loader (database.rs, load single pool by id) when the query itself fails: missing table/column, connection drop, statement timeout, or an identifier string that cannot bind to the column type.

Common situations: Tooling that loads one pool for analysis running while migrations are incomplete; DB connectivity blips during per-pool analysis loops; schema changes renaming a column used in POOL_ROW_COLUMNS.

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

• Failed to load tokens: {e}
• Failed to load pools: {e}
• Failed to seed chain table: {e}
• Failed to call create_block_partition for chain {}: {e}
• Failed to call create_token_partition for chain {}: {e}

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/27ba5bf124b2d2b4. Report an issue: GitHub.