You’re probably aware of the “identity” construct that appeared in 12.1 and uses Oracle’s sequence mechanism to model the Autonumber or Identity columns that other databases have. A posting from Clay Jackson on the Oracle-L list server suggests that something about their code path has introduced a surprising overhead in 19c … when you’re not using them.
The following code is a slightly modified version of a test case that Clay Jackson posted to demonstrate a strange difference in performance between 12.2 and 19.3
