Failed to migrate django db using postgres

Question

I made some changes to my models and then launched

python manage.py makemigrations python manage.py migrate

and I got this trace:

Operations to perform: Synchronize unmigrated apps: staticfiles, messages Apply all migrations: sessions, admin, study, auth, quiz, contenttypes, main Synchronizing apps without migrations: Creating tables... Running deferred SQL... Installing custom SQL... Running migrations: Rendering model states... DONE Applying quiz.0013_auto_20151005_0644...Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 338, in execute_from_command_line utility.execute() File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 330, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 393, in run_from_argv self.execute(*args, **cmd_options) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 444, in execute output = self.handle(*args, **options) File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 222, in handle executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 110, in migrate self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 154, in apply_migration self.recorder.record_applied(migration.app_label, migration.name) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/recorder.py", line 67, in record_applied self.migration_qs.create(app=app, name=name) File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 348, in create obj.save(force_insert=True, using=self.db) File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 734, in save force_update=force_update, update_fields=update_fields) File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 762, in save_base updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields) File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 846, in _save_table result = self._do_insert(cls._base_manager, using, fields, update_pk, raw) File "/usr/local/lib/python2.7/dist-packages/django/db/models/base.py", line 885, in _do_insert using=using, raw=raw) File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 127, in manager_method return getattr(self.get_queryset(), name)(*args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 920, in _insert return query.get_compiler(using=using).execute_sql(return_id) File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 974, in execute_sql cursor.execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 79, in execute return super(CursorDebugWrapper, self).execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute return self.cursor.execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 97, in __exit__ six.reraise(dj_exc_type, dj_exc_value, traceback) File "/usr/local/lib/python2.7/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 "django_migrations_pkey" DETAIL: Key (id)=(27) already exists. 

I did not know how to interpret the error that the primary key already exists. Oddly enough, this added a field to the database because I saw its output on my site, and when I ran the shell, I could see that the fields were added and the default data that I selected was filled.

I decided to start the migration again to check if it will go a second time, and I will get another trace ...

  Operations to perform: Synchronize unmigrated apps: staticfiles, messages Apply all migrations: sessions, admin, study, auth, quiz, contenttypes, main Synchronizing apps without migrations: Creating tables... Running deferred SQL... Installing custom SQL... Running migrations: Rendering model states... DONE Applying quiz.0013_auto_20151005_0644...Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 338, in execute_from_command_line utility.execute() File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 330, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 393, in run_from_argv self.execute(*args, **cmd_options) File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 444, in execute output = self.handle(*args, **options) File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 222, in handle executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 110, in migrate self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 148, in apply_migration state = migration.apply(state, schema_editor) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 115, in apply operation.database_forwards(self.app_label, schema_editor, old_state, project_state) File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards field, File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 398, in add_field self.execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 111, in execute cursor.execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 79, in execute return super(CursorDebugWrapper, self).execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute return self.cursor.execute(sql, params) File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 97, in __exit__ six.reraise(dj_exc_type, dj_exc_value, traceback) File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 64, in execute return self.cursor.execute(sql, params) django.db.utils.ProgrammingError: column "lang1_back_to_choice" of relation "quiz_langpairinstructions" already exists 

Now, if I try again, I will always get a second trace. I wonder what I have to do so that I can migrate to futures. Why am I getting this error if everything seems to go smoothly in the db itself?

Answer 1

I missed the column name "django_migrations_pkey" and I did not understand what was in the database. Somehow the django was one step below the actual database and was trying to use the primary key (pk = 27) instead of the number it was actually on (which should have been 28)

I did not know how to change this from inside django, so instead I just deleted the last column from the database, so it was one of the main keys shorter and on the django track, and it started working fine.

Answer 2

There is another way. Since you know the last id value in the django_migrations table, let's say that it is 100. Then you need to do the following:

 ALTER SEQUENCE django_migrations_id_seq RESTART WITH 101; 

Answer 3

I got this error after I manually redid the django migration table entries manually (after some previously dodgy migrations were added, then deleted).

This left the django_migrations ids out of order (so to speak) with the default position of the django_migrations table.

The problem is that django accepts the identifier of the last record and +1 to create a new record (in the table below: 197 + 1 = 198), however, as you see, Key (id) = (198) already exists in the table.

 187 | foo_app | 0016_auto_20161220_2332 | 2017-01-06 05:22:07.666172+00 198 | bar_app | 0004_auto_20160423_2122 | 2017-01-13 05:38:31.922738+00 197 | baz_app | 0013_auto_20170203_2311 | 2017-02-08 18:50:22.70143+00 

As you can see, the numbers for the primary key on the left are out of order. What I did was manually remove the entries from order in django_migration, and then re-add them.

 DELETE from django_migrations where name = '0004_auto_20160423_2122'; DELETE from django_migrations where name = '0013_auto_20170203_2311'; INSERT INTO django_migrations VALUES (188, 'baz_app', '0013_auto_20170203_2311', date()); INSERT INTO django_migrations VALUES (189, 'bar_app', '0004_auto_20160423_2122', date()); 

It should also be noted that the migration that I originally tried to add "new_app, 0002_auto_00000000_1111" actually changed the new_app table in postgres, however the django_migrations table did not update.

So, the second time I tried to restart the 0002_auto_00000000_1111 migration, I got an error:

 django.db.utils.ProgrammingError: column "new_app_field" of relation "new_app_new" already exists 

My solution above fixed the problem for me.

Answer 4

Just reindexing the django_migrations table worked for me.

Follow these steps in your terminal

Change user to root

 $ sudo su 

So then you change the user to postgres

 $ su postgres 

Open the Postgres terminal client with the selected database

 $ psql name_of_your_db 

In the postgres client, enter the following command

 REINDEX TABLE django_migrations; 

And then exit the postgres client

 \q