SK AX deep-dive

Your real cases as memorizable key points — résumé bullet, deep-dive, code, the lines to say.

• Transactional outbox
  Never wrap an external system call inside your own transaction.
• PK-only payload
  Send identifiers, not state — let the server derive the rest from its source of truth.
• Thin RPC gateway
  Make the middle layer a thin hop, not a boundary that breaks on every upstream change.
• Template Method
  Put behavioral differences in code, and let the domain owner write that code.
• Shared validation
  Shared logic belongs in one layer, never duplicated per surface.
• Don't test on live
  Production is not your sandbox; suspect yourself first.
• PL/SQL → CTEs
  Stabilize the flow before you touch the code; sequence fixes so each one funds the next.
• Dure: TCP framing + broker
  TCP is a byte stream, not messages — frame it yourself
• Distributed lock — granularity
  Lock by the resource you protect — a global lock serializes the wrong things
• Pessimistic lock (FOR UPDATE)
  Lock at the DB — and mind duration, not just scope