08:30:36 Inserting 1 records >> EXCEPTION
08:30:47 Inserting 1 records >> EXCEPTION
09:13:59 Inserting 7 records >> OK
09:14:17 Inserting 18 records >> OK
09:14:27 Inserting 2 records >> OK
09:14:52 Inserting 4 records >> OK
09:15:02 Inserting 4 records >> OK
09:15:13 Inserting 2 records >> OK
09:15:38 Inserting 8 records >> OK
09:26:05 Inserting 1 records >> EXCEPTION
09:42:18 Inserting 5 records >> OK
09:42:28 Inserting 4 records >> OK
10:43:08 Inserting 2 records >> OK
10:43:56 Inserting 13 records >> OK
15:30:14 Inserting 1 records >> OK
15:31:27 Inserting 1 records >> OK
15:31:42 Inserting 1 records >> OK
15:31:44 Inserting 1 records >> OK
15:32:07 Inserting 2 records >> OK
So there is no clear pattern.
WA3) rewrite my code and stop using batch inserts and do single inserts because it doesn't matter if the code takes 30ms instead of 15ms to run
WA4) before batch insert, select X keys from sequence and then insert with those specific keys and stop using the generated keys in the batch methods