{"record":{"id":"8c786f0b137c421d","repo":"nautechsystems/nautilus_trader","slug":"failed-to-get-pool-snapshot-validation-state-e","errorCode":null,"errorMessage":"Failed to get pool snapshot validation state: {e}","messagePattern":"Failed to get pool snapshot validation state: (.+?)","errorType":"exception","errorClass":"anyhow::Error","httpStatus":null,"severity":"error","filePath":"crates/adapters/blockchain/src/cache/database.rs","lineNumber":2638,"sourceCode":"        let row = sqlx::query(\n            \"\n            SELECT validation_state\n            FROM pool_snapshot\n            WHERE chain_id = $1\n            AND pool_identifier = $2\n            AND block = $3\n            AND transaction_index = $4\n            AND log_index = $5\n            \",\n        )\n        .bind(chain_id as i32)\n        .bind(pool_identifier.as_ref())\n        .bind(block as i64)\n        .bind(transaction_index as i32)\n        .bind(log_index as i32)\n        .fetch_optional(&self.pool)\n        .await\n        .map_err(|e| anyhow::anyhow!(\"Failed to get pool snapshot validation state: {e}\"))?;\n\n        Ok(row.map(|row| row.get::<String, _>(\"validation_state\")))\n    }\n\n    /// Loads all positions for a specific snapshot.\n    ///\n    /// # Errors\n    ///\n    /// Returns an error if the database query fails.\n    pub async fn load_pool_positions_for_snapshot(\n        &self,\n        chain_id: u32,\n        pool_identifier: &PoolIdentifier,\n        snapshot_block: u64,\n        snapshot_transaction_index: u32,\n        snapshot_log_index: u32,\n    ) -> anyhow::Result<Vec<PoolPosition>> {\n        let rows = sqlx::query(","sourceCodeStart":2620,"sourceCodeEnd":2656,"githubUrl":"https://github.com/nautechsystems/nautilus_trader/blob/18893faf8b356be3320add8de2f861b0b647cf06/crates/adapters/blockchain/src/cache/database.rs#L2620-L2656","documentation":"This wraps a SQLx failure from the SELECT that reads the persisted `validation_state` for a snapshot at a specific watermark. A missing row is a normal `None` result; this error only fires when the query itself fails (connection, schema, driver issue).","triggerScenarios":"Calling the validation-state getter when Postgres is unreachable, the snapshot table or `validation_state` column doesn't exist (migrations not applied), or the connection pool is exhausted/timed out.","commonSituations":"Adapter running against an unmigrated database after an upgrade; DB restart leaving stale pooled connections; permission changes revoking SELECT on the snapshot table.","solutions":["Verify database connectivity and that migrations created the `validation_state` column.","Check Postgres role grants — SELECT must be allowed on the snapshot table.","Recycle the sqlx connection pool if the DB was recently restarted.","Read the chained `{e}` message for the underlying driver error details."],"exampleFix":"// before: propagate bare error\nlet state = store.get_validation_state(...).await?;\n// after: distinguish empty vs failure and log cause\nlet state = store.get_validation_state(...).await\n    .map_err(|e| { tracing::warn!(cause = ?e.source(), \"validation state read failed\"); e })?;","handlingStrategy":"try-catch","validationCode":"sqlx::query(\"SELECT 1\").execute(&db).await?; // cheap liveness probe before state reads","typeGuard":null,"tryCatchPattern":"let state = match store.get_validation_state(...).await {\n    Ok(s) => s, // None simply means no row\n    Err(e) if is_transient(&e) => { backoff_and_retry().await }\n    Err(e) => return Err(e),\n};","preventionTips":["Treat Ok(None) as the normal 'no snapshot' path; only errors need handling.","Verify SELECT grants for the adapter's DB role.","Recycle/rebuild the connection pool after DB restarts."],"tags":["database","postgres","sqlx","read-failed"],"backgroundTag":"database-query-failed","analyzedSha":"18893faf8b356be3320add8de2f861b0b647cf06","analyzedAt":"2026-09-08T20:49:34.690Z","contentChangedAt":"2026-09-08T20:49:34.690Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}