Optimization fails with database locked error on high load

[ronald-jaepel]

"""
Traceback (most recent call last):
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/joblib/externals/loky/process_executor.py", line 463, in _process_worker
    r = call_item()
        ^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/joblib/externals/loky/process_executor.py", line 291, in __call__
    return self.fn(*self.args, **self.kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/joblib/parallel.py", line 598, in __call__
    return [func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/joblib/parallel.py", line 598, in <listcomp>
    return [func(*args, **kwargs)
            ^^^^^^^^^^^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/CADETProcess/optimization/optimizationProblem.py", line 1675, in evaluate_callbacks
    self._evaluate(ind.x, callback, force)
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/CADETProcess/optimization/optimizationProblem.py", line 850, in _evaluate
    result = self.cache.get(key)
             ^^^^^^^^^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/CADETProcess/optimization/cache.py", line 122, in get
    value = self.cache[key]
            ~~~~~~~~~~^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/diskcache/fanout.py", line 301, in __getitem__
    return shard[key]
           ~~~~~^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/diskcache/core.py", line 1232, in __getitem__
    value = self.get(key, default=ENOVAL, retry=True)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/IBT/jaepel/miniforge3/envs/rdm_example/lib/python3.11/site-packages/diskcache/core.py", line 1165, in get
    rows = self._sql(select, (db_key, raw, time.time())).fetchall()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sqlite3.OperationalError: database is locked
"""