What causes "Failed to load general table: {e}" in nautechsystems/nautilus_trader?

Run the current migrations so the `general` table and column types match this crate version.

Failed to load general table: {e}

Error message

Failed to load general table: {e}

What it means

`DatabaseQueries::load` runs `SELECT * FROM general` and decodes every row into an `AHashMap<String, Vec<u8>>`, wrapping any sqlx failure in this anyhow error. Failure means the query or row decoding failed: connectivity loss, missing table, or schema/data drift where stored values no longer match the expected row types.

Source

Thrown at crates/infrastructure/src/sql/queries.rs:95

    }

    /// Loads all entries from the `general` table via the provided `pool`.
    ///
    /// # Errors
    ///
    /// Returns an error if the SELECT operation fails.
    pub async fn load(pool: &PgPool) -> anyhow::Result<AHashMap<String, Vec<u8>>> {
        sqlx::query_as::<_, GeneralRow>("SELECT * FROM general")
            .fetch_all(pool)
            .await
            .map(|rows| {
                let mut cache: AHashMap<String, Vec<u8>> = AHashMap::new();
                for row in rows {
                    cache.insert(row.id, row.value);
                }
                cache
            })
            .map_err(|e| anyhow::anyhow!("Failed to load general table: {e}"))
    }

    /// Inserts or ignores a `Currency` row via the provided `pool`.
    ///
    /// # Errors
    ///
    /// Returns an error if the INSERT operation fails.
    pub async fn add_currency(pool: &PgPool, currency: Currency) -> anyhow::Result<()> {
        sqlx::query(
            "INSERT INTO currency (id, precision, iso4217, name, currency_type) VALUES ($1, $2, $3, $4, $5::currency_type) ON CONFLICT (id) DO NOTHING"
        )
            .bind(currency.code.as_str())
            .bind(i32::from(currency.precision))
            .bind(i32::from(currency.iso4217))
            .bind(currency.name.as_str())
            .bind(CurrencyTypePg(currency.currency_type))
            .execute(pool)
            .await

View on GitHub (pinned to 18893faf8b)

Solutions

Run the current migrations so the `general` table and column types match this crate version.
Confirm DATABASE_URL targets the intended cache database.
If rows were written by a mismatched version, clear or migrate the `general` table before loading.
Read the inner sqlx error: 'relation does not exist' means run migrations; 'error decoding' means schema drift.

Defensive patterns

Strategy: try-catch

Validate before calling

let exists: bool = sqlx::query_scalar(
    "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = 'general')",
).fetch_one(pool).await?;
if !exists {
    return Err(anyhow::anyhow!("'general' table missing — run migrations"));
}

Try / catch

match DatabaseQueries::load(&pool).await {
    Err(e) if e.to_string().contains("relation \"general\" does not exist") => {
        return Err(anyhow::anyhow!("cache schema missing — run migrations: {e}"));
    }
    result => result?,
}

Prevention

Run matching migrations whenever you upgrade the application version.
Verify DATABASE_URL points at the intended cache database on startup.
Avoid mixing cache databases written by incompatible schema versions.
Inspect the inner sqlx error text to classify failures (missing table vs decode drift).

When it happens

Trigger: Calling `DatabaseQueries::load(pool)` when the connection fails, the `general` table doesn't exist (migrations missing), or GeneralRow decoding fails because rows were written by a different schema version (e.g. column type changed between releases).

Common situations: Loading the cache on startup against a database created by an older or newer schema version; pointing at the wrong database; transient network failure during a large fetch.

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/ffe57a1d8ccc1944. Report an issue: GitHub.