```
Nov 27 16:17:32 storage1 python3[28595]: 2020-11-27 16:17:32 [28595] root:ERROR there is no unique or exclusion constraint matching the ON CONFLICT specification
                                         CONTEXT:  SQL statement "insert into indexer_configuration(tool_name, tool_version, tool_configuration)
                                               select tool_name, tool_version, tool_configuration from tmp_indexer_configuration tmp
                                               on conflict(tool_name, tool_version, tool_configuration) do nothing"
                                         PL/pgSQL function swh_indexer_configuration_add() line 3 at SQL statement
                                         Traceback (most recent call last):
                                           File "/usr/lib/python3/dist-packages/flask/app.py", line 1813, in full_dispatch_request
                                             rv = self.dispatch_request()
                                           File "/usr/lib/python3/dist-packages/flask/app.py", line 1799, in dispatch_request
                                             return self.view_functions[rule.endpoint](**req.view_args)
                                           File "<decorator-gen-54>", line 2, in indexer_configuration_add
                                           File "/usr/lib/python3/dist-packages/swh/core/api/negotiation.py", line 147, in _negotiate
                                             return f.negotiator(*args, **kwargs)
                                           File "/usr/lib/python3/dist-packages/swh/core/api/negotiation.py", line 81, in __call__
                                             result = self.func(*args, **kwargs)
                                           File "/usr/lib/python3/dist-packages/swh/core/api/__init__.py", line 458, in _f
                                             return obj_meth(**kw)
                                           File "/usr/lib/python3/dist-packages/swh/indexer/storage/metrics.py", line 24, in d
                                             return f(*a, **kw)
                                           File "/usr/lib/python3/dist-packages/swh/core/db/common.py", line 62, in _meth
                                             return meth(self, *args, db=db, cur=cur, **kwargs)
                                           File "/usr/lib/python3/dist-packages/swh/indexer/storage/__init__.py", line 689, in indexer_configuration_add
                                             results = [dict(zip(db.indexer_configuration_cols, line)) for line in tools]
                                           File "/usr/lib/python3/dist-packages/swh/indexer/storage/__init__.py", line 689, in <listcomp>
                                             results = [dict(zip(db.indexer_configuration_cols, line)) for line in tools]
                                           File "/usr/lib/python3/dist-packages/swh/indexer/storage/db.py", line 520, in indexer_configuration_add_from_temp
                                             % (",".join(self.indexer_configuration_cols),)
                                         psycopg2.errors.InvalidColumnReference: there is no unique or exclusion constraint matching the ON CONFLICT specification
                                         CONTEXT:  SQL statement "insert into indexer_configuration(tool_name, tool_version, tool_configuration)
                                               select tool_name, tool_version, tool_configuration from tmp_indexer_configuration tmp
                                               on conflict(tool_name, tool_version, tool_configuration) do nothing"
                                         PL/pgSQL function swh_indexer_configuration_add() line 3 at SQL statement
Nov 27 16:17:32 storage1 python3[28595]: 2020-11-27 16:17:32 [28595] gunicorn.access:INFO  - - [27/Nov/2020:16:17:32 +0000] "POST /indexer_configuration/add HTTP/1.0" 500 2959 "-" "python-requests/2.21.0"
```