[cnlwsu]

You’re describing compare and swap which is a good solution. You’re pushing complexity down to the database, and remember this is distributed locking. When you have a single database it’s simple until the database crashes leaving you in state of not knowing which of your CAS writes took effect. In major systems that demand high availability and multi datacenter backups this becomings pretty complicated with scenarios that break this as well around node failure. Usually some form of paxos transaction log is used. Never assume there is an easy solution in distributed systems… it just always sucks