Michael Glaesemann <grzm@xxxxxxxxxxxxxxx> writes: > However, my point regarding the example in the docs still holds. Why > is the exception block necessary? Doesn't wrapping the statements in a > function ensure the unique_violation couldn't occur? Well, the point of that example is to deal correctly with the case where two sessions try to insert the same key concurrently. The second to reach the index insertion point will see the conflicting index entry already there, and it will block until it sees the other transaction commit or abort, and if commit it will then throw a unique exception. Are you certain that concurrent executions of purchase() for the same item_id can never happen in your system? Because that certainly seems the most likely explanation from here. regards, tom lane
