SQL error: duplicate key value

[jeroen-80]

Internal Server Error: /profile
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
psycopg2.IntegrityError: duplicate key value violates unique constraint "user_sessions_session_pkey"
DETAIL:  Key (session_key)=(kjko1b7gickvf3kx06y9v2lu83c8frc9) already exists.


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/deprecation.py", line 142, in __call__
    response = self.process_response(request, response)
  File "./user_sessions/middleware.py", line 69, in process_response
    request.session.save()
  File "./user_sessions/backends/db.py", line 97, in save
    obj.save(force_insert=must_create, using=using)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 808, in save
    force_update=force_update, update_fields=update_fields)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 838, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 924, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 963, in _do_insert
    using=using, raw=raw)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 1076, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/compiler.py", line 1112, in execute_sql
    cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
django.db.utils.IntegrityError: duplicate key value violates unique constraint "user_sessions_session_pkey"
DETAIL:  Key (session_key)=(kjko1b7gickvf3kx06y9v2lu83c8frc9) already exists.

Python 3.5, Django 1.11. Proposed fix: check session key before passing it to SQL.

[Bouke]

The code is modelled after django’s own middleware. I suggest we keep doing that. Does the same problem also exist in their code, or did that code change since we forked the code?