#Lock

2 posts

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  Implementing FCFS with DB Locks: From FOR UPDATE to Concurrency Testing

  Mar 20, 2026

  Implements a first-come-first-served stock deduction system using SELECT FOR UPDATE. Builds it with Spring Boot + JPA, validates data consistency with 100 concurrent requests, and identifies where DB locks hit their limits.

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  Deadlocks and Lock Strategies by Isolation Level: From Pessimistic Locks to FOR UPDATE's Limits

  Mar 17, 2026

  Real deadlock cases at each isolation level — Read Committed, Repeatable Read, and Serializable. Covers pessimistic vs optimistic locking, FOR UPDATE mechanics, and why you'll eventually need Redis.