Jupyter: database is locked / can not load notebook format
Link to section 'Problem' of 'Jupyter: database is locked / can not load notebook format' Problem
You receive the following message after trying to load existing Jupyter notebooks inside your JupyterHub session:
Error loading notebook
An unknown error occurred while loading this notebook. This version can load notebook formats or earlier. See the server log for details.
Alternatively, the notebook may open but present an error when creating or saving a notebook:
Autosave Failed!
Unexpected error while saving file: MyNotebookName.ipynb database is locked
Link to section 'Solution' of 'Jupyter: database is locked / can not load notebook format' Solution
When Jupyter notebooks are opened, the server keeps track of their state in an internal database (located inside ~/.local/share/jupyter/ folder in your home directory). If a Jupyter process gets terminated abruptly (e.g. due to an out-of-memory error or a host reboot), the database lock is not cleared properly, and future instances of Jupyter detect the lock and complain.
Please follow these steps to resolve:
- Fully exit from your existing Jupyter session (close all notebooks, terminate Jupyter, log out from JupyterHub or JupyterLab, terminate OnDemand gateway's Jupyter app, etc).
- In a terminal window (SSH, Thinlinc or OnDemand gateway's terminal app) use the following command to clean up stale database locks:
$ unlock-jupyter - Start a new Jupyter session as usual.