Architecture: DB2 for z/OS

A payment transaction hits the mainframe. It needs to check an account balance, verify a credit limit, write an audit record, and update three tables atomically. All of this happens under a single unit of work, coordinated by a database that has been running at that bank since the 1980s. If any part fails, every change rolls back. If two transactions try to update the same row simultaneously, one waits. If the system crashes mid-transaction, the… Read More