alt Hacker NewsThis seems to assume retrying a command should result in the same response, but I am not sure I agree.
Idempotency is about state, not communication. Send the same payment twice and one of them should respond "payment already exists".
Replies
raffael_de • today at 11:04 AM
> Send the same payment twice and one of them should respond "payment already exists".
You are hiding the relevant complexity in the term "same". What is here the same? I mean, if accidentally buy only 1 instead of two items of a product and then buy afterwards again 1 item. How is this then the same or not the same payment?
➕ show 1 reply
cocoto • today at 10:04 AM
In your example, idempotency means same request + same state = same response. State becomes part of the request, that’s why it is hard.
➕ show 1 reply
I don’t know if we’re reading the same article? The linked one states very plainly:
”Idempotency is about the effect
An operation is idempotent if applying it once or many times has the same intended effect.”