This commit affects `check_for_dupid()` helper: * Add a special, quicker code path dedicated to sequential addition of a large number of IDs using the same base name. This gives a significant speedup to adding 'randomly'-named IDs: | Number and type of names of IDs | old code | new code | speed improvement | | -------------------------------- | -------- | -------- | ----------------- | | 40K, mixed (14k rand, 26k const) | 49s | 39s | 26% | | 40K, fully random | 51s | 51s | 0% | | 40K, fully constant | 71s | 40s | 78% | Note that 'random' names give no improvement as expected, since this new code path will never be used in such cases.