id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 30743 Removing `db_index=True` crashes migrations. John Tsai nobody "When I switch from a development branch to the testing branch, the `db_index=True` was removed. But migration failed and raised such error: {{{ Traceback (most recent call last): File ""./manage.py"", line 10, in execute_from_command_line(sys.argv) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/__init__.py"", line 381, in execute_from_command_line utility.execute() File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/__init__.py"", line 375, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/base.py"", line 323, in run_from_argv self.execute(*args, **cmd_options) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/base.py"", line 364, in execute output = self.handle(*args, **options) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/base.py"", line 83, in wrapped res = handle_func(*args, **kwargs) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/core/management/commands/migrate.py"", line 234, in handle fake_initial=fake_initial, File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/migrations/executor.py"", line 117, in migrate state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/migrations/executor.py"", line 147, in _migrate_all_forwards state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/migrations/executor.py"", line 245, in apply_migration state = migration.apply(state, schema_editor) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/migrations/migration.py"", line 124, in apply operation.database_forwards(self.app_label, schema_editor, old_state, project_state) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/migrations/operations/fields.py"", line 249, in database_forwards schema_editor.alter_field(from_model, from_field, to_field) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py"", line 535, in alter_field old_db_params, new_db_params, strict) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/postgresql/schema.py"", line 124, in _alter_field new_db_params, strict, File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py"", line 603, in _alter_field exclude=meta_index_names, File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/base/schema.py"", line 1115, in _constraint_names constraints = self.connection.introspection.get_constraints(cursor, model._meta.db_table) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/postgresql/introspection.py"", line 175, in get_constraints """""", [""public"", table_name]) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/utils.py"", line 67, in execute return self._execute_with_wrappers(sql, params, many=False, executor=self._execute) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/utils.py"", line 76, in _execute_with_wrappers return executor(sql, params, many, context) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/utils.py"", line 85, in _execute return self.cursor.execute(sql, params) File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/utils.py"", line 89, in __exit__ raise dj_exc_value.with_traceback(traceback) from exc_value File ""/usr/local/blesssystem/venv/lib/python3.6/site-packages/django/db/backends/utils.py"", line 85, in _execute return self.cursor.execute(sql, params) psycopg2.errors.SyntaxError: syntax error at or near ""WITH ORDINALITY"" LINE 6: FROM unnest(c.conkey) WITH ORDINALITY co... }}} I tried to print out the executing migrate query {{{ #!sql SELECT c.conname, array( SELECT attname FROM unnest(c.conkey) WITH ORDINALITY cols(colid, arridx) JOIN pg_attribute AS ca ON cols.colid = ca.attnum WHERE ca.attrelid = c.conrelid ORDER BY cols.arridx ), c.contype, (SELECT fkc.relname || '.' || fka.attname FROM pg_attribute AS fka JOIN pg_class AS fkc ON fka.attrelid = fkc.oid WHERE fka.attrelid = c.confrelid AND fka.attnum = c.confkey[1]), cl.reloptions FROM pg_constraint AS c JOIN pg_class AS cl ON c.conrelid = cl.oid JOIN pg_namespace AS ns ON cl.relnamespace = ns.oid WHERE ns.nspname = %s AND cl.relname = %s }}} I also tried another way to create the index, and it seems working well after removing it. {{{ #!python class MyModel(models.Model): my_field = models.CharField(max_length=64, db_index=True) # will crash after removed class Meta: # fine even if removed indexes = [ models.Index(fields=['my_field']) ] }}} I could not find any solution to solve it in Python code (Remove by `dbshell` and use fake migrate might work though). But I believe the **Meta** version works, then **db_index** might work too. ---- Environment django version 2.2.3 postgreSQL 9.5.13 psycopg2-binary 2.8.2 " Bug closed Database layer (models, ORM) dev Normal worksforme postgres, db_index Unreviewed 0 0 0 0 0 0