Constant DIRECTIVE_OUTBOX_DELIVERY_METRICS_SQL 

const DIRECTIVE_OUTBOX_DELIVERY_METRICS_SQL: &str = r#"
SELECT
    action_key::text AS action_key,
    delivery_status,
    COUNT(*)::BIGINT AS pending_count,
    SUM(
        CASE
            WHEN delivery_attempts > 0 OR last_delivery_error IS NOT NULL THEN 1
            ELSE 0
        END
    )::BIGINT AS retrying_count,
    GREATEST(
        MAX(EXTRACT(EPOCH FROM (CURRENT_TIMESTAMP - to_timestamp(created_ts_ms / 1000.0))))::BIGINT,
        0
    ) AS oldest_created_age_seconds,
    GREATEST(
        MAX(EXTRACT(EPOCH FROM (
            CURRENT_TIMESTAMP - COALESCE(last_attempt_at, to_timestamp(created_ts_ms / 1000.0))
        )))::BIGINT,
        0
    ) AS oldest_attempt_age_seconds
FROM directive_outbox
WHERE tx_hash IS NULL
  AND delivery_status IN ('pending', 'broadcasted')
GROUP BY action_key, delivery_status
"#;