Comment 4 for bug 1866068

Adding the original trace for search purposes:

2020-02-29 02:54:15.684 22 DEBUG ovsdbapp.backend.ovs_idl.transaction [-] Running txn n=1 command(idx=1): PgAddCommand(name=neutron_pg_drop, may_exist=True, columns={'acls': []}) do_commit /usr/lib/python3.6/site-packages/ovsdbapp/backend/ovs_idl/transaction.py:84
...
2020-02-29 02:54:15.690 22 ERROR ovsdbapp.backend.ovs_idl.transaction [-] OVSDB Error: {"details":"Transaction causes multiple rows in \"Port_Group\" table to have identical values (neutron_pg_drop) for index on column \"name\". First row, with UUID 2025ff8b-f8b0-4f39-9fdf-9b48b1a02b7a, was inserted by this transaction. Second row, with UUID f516334e-d700-4f65-8aaa-abb5c4fd465a, existed in the database before this transaction and was not modified by the transaction.","error":"constraint violation"}
2020-02-29 02:54:15.691 22 ERROR ovsdbapp.backend.ovs_idl.transaction [req-ab175c93-b83b-4345-bec6-deef1829aec6 3cbd95c02380422ca96bc3de8418bcc0 99ee3dee19754d168d47c35e9337db20 - default default] Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/ovsdbapp/backend/ovs_idl/connection.py", line 122, in run
    txn.results.put(txn.do_commit())
  File "/usr/lib/python3.6/site-packages/ovsdbapp/backend/ovs_idl/transaction.py", line 115, in do_commit
    raise RuntimeError(msg)
RuntimeError: OVSDB Error: {"details":"Transaction causes multiple rows in \"Port_Group\" table to have identical values (neutron_pg_drop) for index on column \"name\". First row, with UUID 2025ff8b-f8b0-4f39-9fdf-9b48b1a02b7a, was inserted by this transaction. Second row, with UUID f516334e-d700-4f65-8aaa-abb5c4fd465a, existed in the database before this transaction and was not modified by the transaction.","error":"constraint violation"}