Permission denied for relation django_migrations using Heroku - django

Question

While attempting to migrate database changes using django on Heroku, I get:
psycopg2.ProgrammingError: permission denied for relation django_migrations
Other people have been able to resolve this issue by granting the appropriate privileges (e.g., Permission denied for relation). Unfortunately, I can't grant permissions or create a new user on the Heroku hobby tier.
I was able to roll back a few migrations, but eventually I got:
django.db.utils.ProgrammingError: table "labs_branch_tests" does not exist
and could not migrate back to newer migrations.
Full traceback for permission denied for relation django_migrations
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
utility.execute()
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 356, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
self.execute(*args, **cmd_options)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
output = self.handle(*args, **options)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 204, in handle
fake_initial=fake_initial,
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 115, in migrate
state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 250, in apply_migration
self.recorder.record_applied(migration.app_label, migration.name)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 73, in record_applied
self.migration_qs.create(app=app, name=name)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/query.py", line 394, in create
obj.save(force_insert=True, using=self.db)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py", line 807, in save
force_update=force_update, update_fields=update_fields)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py", line 837, in save_base
updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py", line 923, in _save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/base.py", line 962, in _do_insert
using=using, raw=raw)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/query.py", line 1076, in _insert
return query.get_compiler(using=using).execute_sql(return_id)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 1107, in execute_sql
cursor.execute(sql, params)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: permission denied for relation django_migrations
Full traceback for psycopg2.ProgrammingError: table "labs_branch_tests" does not exist
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
utility.execute()
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/__init__.py", line 356, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
self.execute(*args, **cmd_options)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
output = self.handle(*args, **options)
File "/app/.heroku/python/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 204, in handle
fake_initial=fake_initial,
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 119, in migrate
state = self._migrate_all_backwards(plan, full_plan, fake=fake)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 194, in _migrate_all_backwards
self.unapply_migration(states[migration], migration, fake=fake)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/executor.py", line 264, in unapply_migration
state = migration.unapply(state, schema_editor)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/migration.py", line 178, in unapply
operation.database_backwards(self.app_label, schema_editor, from_state, to_state)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 95, in database_backwards
schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 457, in remove_field
return self.delete_model(field.remote_field.through)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 324, in delete_model
"table": self.quote_name(model._meta.db_table),
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 120, in execute
cursor.execute(sql, params)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/app/.heroku/python/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
raise value.with_traceback(tb)
File "/app/.heroku/python/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: table "labs_branch_tests" does not exist

Answer 1

I was able to get around this by granting privileges to the user in the postgres terminal.
First connect to postgres through the Heroku CLI (heroku pg:psql).
This is clunky but get your Heroku postgres username by calling \c in the postgres terminal. (The last line of output will be You are now connected to database DATABASE_NAME as user USERNAME.)
Then grant privileges as others have shown:
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public to USERNAME;
GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public to USERNAME;
GRANT ALL PRIVILEGES ON ALL FUNCTIONS IN SCHEMA public to USERNAME;

Answer 2

In my case this was because my free database reached its row limit and write access was revoked:
$ heroku pg:info
=== DATABASE_URL
Plan: Hobby-dev
Status: Available
Connections: 0/20
PG Version: 10.4
[..]
Rows: 11683/10000 (Write access revoked)
[..]

Answer 3

for me yes you can tell the write access was revoked with
$ heroku pg:info
...
Rows: 11683/10000 (Write access revoked)
but I didn't want to dump the whole database. Instead I identify the biggest tables with
$ heroku pg:psql
> select
table_name
, pg_relation_size(quote_ident(table_name)) as "raw_size"
, pg_size_pretty(pg_relation_size(quote_ident(table_name)) as "size"
from information_schema.tables
where table_schema = 'public'
order by "raw_size" desc;
and then I clear the biggest tables with
> delete from <table name>;