[pdonis]

> There are a lot of ways to implement this

Sure, I get that. What I don't get is why you would be using idempotency keys as part of the implementation if you're going to go ahead and start a second transaction when you get a duplicate request, and not even check the idempotency key, and let your database tell you you've got a duplicate when you try to commit the second transaction. This subthread is specifically about implementations that use idempotency keys, since that's what the article is about.

[pdonis]

Update: stickfigure basically answered this in another subthread: as I understand the answer, it is that you do check the idempotency key, but inside the DB transaction, so you have to start a new transaction on every request. If, inside the transaction, your idempotency key check shows that another request with that key was already received, you don't do anything to change the DB inside the transaction and just commit it as a no-op.