One of the developers was performing a delete using a nested subquery, which was throwing out ORA-00600 errors. The ORA-00600 Lookup Tool on MOS suggested it was caused by this bug:
The workaround in the bug suggested running this ALTER SESSION command.
alter session set "_optimizer_unnest_disjunctive_subq"= FALSE;
Rather than alter the whole session, we used the OPT_PARAM hint, making the subquery look something like this.
The APPEND_VALUES hint is new to 11gR2 and allows you to use direct-path inserts from “INSERT INTO … VALUES” type statements. Pretty neat if you are doing inserts in a FORALL statement and need the extra punch.