Tag: Lock

All the articles with the tag "Lock".

• MySQL Credit Deduction — 4 Locks Compared, Pessimistic at 180ms / 100% accurate, plus the self-invocation trap I hit during measurement

  4 May, 2026

  An ordinary scenario — 100 workers concurrently subtracting 1 from an account with balance 100. Four lock strategies (optimistic / pessimistic / MySQL GET_LOCK / Redisson) all produce different results — pessimistic 180ms / 100% / balance 0, optimistic 549ms (retry storm under contention), GET_LOCK 5015ms (advisory lock cost), Redisson 53/100 (single-instance limitation). And during measurement I hit the self-invocation trap — successes=100 but the balance never moved. The real Spring/JPA pitfall is not logic, it is AOP proxy bypass. A walkthrough including direct demos of the connection-bound GET_LOCK traps in 4 scenarios.