Django writes session_data with incorrect hash

[David Owen]

Django occasionally updates the session table with data with bad hashes. The session_data column is formatted as a string of the hash (base64), a colon, and the pickled data (base64-encoded).

This bug seemed to be triggered by long database operations (e.g. the "monster" query that would take several minutes), and would cause the request-handler to error-out.

This is hypothesis so far; actual cause unknown.