https://github.com/andreacrotti/django-migrations-analysis

https://github.com/andreacrotti/django-migrations-analysis

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• Host: GitHub
• URL: https://github.com/andreacrotti/django-migrations-analysis
• Owner: AndreaCrotti
• Created: 2016-10-03T12:31:34.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2016-10-07T11:06:51.000Z (over 9 years ago)
• Last Synced: 2025-02-01T09:13:16.952Z (over 1 year ago)
• Language: Python
• Size: 45.9 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Django migrations analysis

Various attempts to solve Django very slow migrations issues.

Various useful links:

https://groups.google.com/forum/#!msg/django-users/V8Ei2qZJ8VI/bFUeY2wTAQAJ;context-place=forum/django-users

[1] https://github.com/django/django/commit/a1ba4627931591b80afa46e38e261f354151d91a 

[2] https://code.djangoproject.com/ticket/24225 

[3] https://github.com/django/django/commit/5aa55038ca9ac44b440b56d1fc4e79c876e51393 

[4] https://code.djangoproject.com/ticket/24745 

[5] https://github.com/MarkusH/django/commits/schemaeditor-modelstate 

## Tasks

- capture output from RunPython calls

- see if it's feasible to not allow anymore to use RunPython

- find out why we get this error with the `schema_editor` branch from Markus

    File "./manage.py", line 10, in 

        execute_from_command_line(sys.argv)

      File "/home/andrea/code/django-faster-migration/django/core/management/__init__.py", line 362, in execute_from_command_line

        utility.execute()

      File "/home/andrea/code/django-faster-migration/django/core/management/__init__.py", line 354, in execute

        self.fetch_command(subcommand).run_from_argv(self.argv)

      File "/home/andrea/code/django-faster-migration/django/core/management/base.py", line 297, in run_from_argv

        self.execute(*args, **cmd_options)

      File "/home/andrea/code/django-faster-migration/django/core/management/base.py", line 348, in execute

        output = self.handle(*args, **options)

      File "/home/andrea/code/django-faster-migration/django/core/management/commands/migrate.py", line 177, in handle

        executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)

      File "/home/andrea/code/django-faster-migration/django/db/migrations/executor.py", line 92, in migrate

        self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)

      File "/home/andrea/code/django-faster-migration/django/db/migrations/executor.py", line 115, in _migrate_all_forwards

        state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)

      File "/home/andrea/code/django-faster-migration/django/db/migrations/executor.py", line 186, in apply_migration

        state = migration.apply(state, schema_editor)

      File "/home/andrea/code/django-faster-migration/django/db/migrations/migration.py", line 129, in apply

        operation.database_forwards(self.app_label, schema_editor, old_state, project_state)

      File "/home/andrea/code/django-faster-migration/django/db/migrations/operations/models.py", line 486, in database_forwards

        to_model_state.options.get(self.option_name, set()),

      File "/home/andrea/code/django-faster-migration/django/db/backends/sqlite3/schema.py", line 261, in alter_unique_together

        self._remake_table(model, override_uniques=new_unique_together)

      File "/home/andrea/code/django-faster-migration/django/db/backends/sqlite3/schema.py", line 80, in _remake_table

        body = {f.name: f for f in model._meta.local_concrete_fields}

    AttributeError: 'ModelStateOptions' object has no attribute 'local_concrete_fields'

## Usage

Running migrations has to be done in different steps:

- *dump_run_python* runs a full migration on an empty database, generating SQL files from migrations that are using RunPython

- *make_raw_migration*:

    same as make_migrations but creates python module migration and corresponding SQL file, it *does not* actually support RunPython calls

    Can be run on both an empty and a non empty databae, but will fail loudly on an existing database with new RunPython code.

- *migrate_raw*:

     same as migrate but uses the SQL files, so bypassing completely everything all the Python loading, but using the same order to load the files

     in, updating the django-migrations table accordingly.

Migrations of external apps (content_type/auth etc) shoudl actually still be done in the usual way.

This simplifies a lot things since then everything else has migration files in the expected path.