Reliability

Balance Calculation Methodology

The balance value is dynamically computed using data from the transactions table. This computation is triggered whenever a transaction is either added or updated within the system. This approach ensures that the balance reflects the most current state of transactions, thereby mitigating the risk associated with direct modifications to the balance record itself.

The formula for calculating the balance is as follows: funds_received - funds_sent, where:

funds_received is calculated using the query:

SELECT SUM(transactions.received)
FROM transactions
WHERE transactions.status IN (<accounting-statuses>)

funds_sent is derived from:

SELECT SUM(transactions.amount)
FROM transactions
WHERE transactions.status IN (<accounting-statuses>)

For detailed information on the specific accounting-statuses referenced, please consult the configuration documentation.

Ensuring Balance Accuracy

To safeguard against data inconsistencies during concurrent transaction processing, the system employs database-level locking on the balance record. This lock remains until the balance has been recalculated, ensuring transactional integrity. Furthermore, the transaction creator class is designed to fetch the latest balance data immediately upon initiating a transaction. This guarantees that transaction processing is based on the most current balance information, thereby enhancing the reliability of the balance calculation process.

Rollback Mechanism Enhancement

The system incorporates a sophisticated rollback mechanism designed to automatically revert any modifications made to the database, should an exception occur. This capability is indispensable, particularly during the execution of before and after callbacks as defined within the transaction creator. By utilizing this mechanism, the system ensures the database's integrity remains intact, safeguarding against data corruption or inconsistency resulting from unforeseen errors. This proactive approach to error handling enhances system reliability and trustworthiness, ensuring smooth and secure operations.