Converting an existing MyISAM database to InnoDB with Django

Question

Is there anyway I can convert a full populated MyISAM database to InnoDB (in a way that will create all foreign key contraints, same way it would be if I ran the syncdb command

Answer 1

Converting MyISAM to InnoDB with Django.

Given the old database is in MyISAM.

Dump the data of old database to json with:

$ python manage.py dumpdata contenttypes --indent=4 --natural > contenttype.json
$ python manage.py dumpdata --exclude contenttypes --indent=4 --natural > everything_else.json

Delete the old database, and create it again.

Add InnoDB settings in your settings.py like this:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'STORAGE_ENGINE': 'InnoDB',
        'NAME': 'yourdbname',
        'USER': '',
        'PASSWORD': '',
        'HOST': '',
        'PORT': '',
        'OPTIONS': {
            'init_command': 'SET storage_engine=InnoDB',  # better to set this in your database config, otherwise django has to do a query everytime
        }
    }
}

Create tables (django also adds the relations) Make sure you don't add an admin user:

$ python manage.py syncdb --migrate

Now you want to empty all the old tables:

$ python manage.py sqlflush | ./manage.py dbshell

Now you can load the new data into the database like so:

$ python manage.py loaddata contenttype.json
$ python manage.py loaddata everything_else.json

There you go. I used Django==1.4 for this.

Answer 2

I had a similar situation where I didn't realize my hosting provider had such an old MySQL version that it still defaulted to MyISAM, but I'd already set up the basic Django tables.

This was posted about 2 months after the original question: Convert Legacy Django MySQL DBS from MyISAM to InnoDB.

That and leech/Trey's answer describe the ALTER TABLE ___ ENGINE=INNODB command that converts the table in MySQL, but the problem is that even though the tables are converted, they don't have the foreign key constraints that would have been set up if the tables had been INNODB in the first place.

I found, on django-admin.py and manage.py, that python manage.py sqlall appname "prints the CREATE TABLE and initial-data SQL statements for the given app name(s)."

I looked at INSTALLED_APPS in settings.py and ended up running something like python manage.py sqlall admin auth contenttypes sessions sites messages staticfiles (one for each django.contrib.appname in INSTALLED_APPS). That showed the initial CREATE TABLE statements, indexes and foreign key constraints:

ALTER TABLE `django_admin_log` ADD CONSTRAINT `content_type_id_refs_id_288599e6` FOREIGN KEY (`content_type_id`) REFERENCES `django_content_type` (`id`);
ALTER TABLE `django_admin_log` ADD CONSTRAINT `user_id_refs_id_c8665aa` FOREIGN KEY (`user_id`) REFERENCES `auth_user` (`id`);
ALTER TABLE `auth_permission` ADD CONSTRAINT `content_type_id_refs_id_728de91f` FOREIGN KEY (`content_type_id`) REFERENCES `django_content_type` (`id`);
ALTER TABLE `auth_group_permissions` ADD CONSTRAINT `permission_id_refs_id_a7792de1` FOREIGN KEY (`permission_id`) REFERENCES `auth_permission` (`id`);
ALTER TABLE `auth_group_permissions` ADD CONSTRAINT `group_id_refs_id_3cea63fe` FOREIGN KEY (`group_id`) REFERENCES `auth_group` (`id`);
ALTER TABLE `auth_user_user_permissions` ADD CONSTRAINT `permission_id_refs_id_67e79cb` FOREIGN KEY (`permission_id`) REFERENCES `auth_permission` (`id`);
ALTER TABLE `auth_user_groups` ADD CONSTRAINT `group_id_refs_id_f0ee9890` FOREIGN KEY (`group_id`) REFERENCES `auth_group` (`id`);
ALTER TABLE `auth_user_user_permissions` ADD CONSTRAINT `user_id_refs_id_f2045483` FOREIGN KEY (`user_id`) REFERENCES `auth_user` (`id`);
ALTER TABLE `auth_user_groups` ADD CONSTRAINT `user_id_refs_id_831107f1` FOREIGN KEY (`user_id`) REFERENCES `auth_user` (`id`);
ALTER TABLE `auth_message` ADD CONSTRAINT `user_id_refs_id_9af0b65a` FOREIGN KEY (`user_id`) REFERENCES `auth_user` (`id`);

After converting all the tables to ENGINE=INNODB I ran the foreign key constraints above and believe I should have the database in the same state as it would have been if my database had defaulted to creating INNODB tables in the first place.

Incidentally, as Michael van de Waeter mentioned in his answer, if you want any new tables Django creates to be INNODB by default, you should add 'OPTIONS': {"init_command": "SET storage_engine=INNODB",} to the DATABASES dict in settings.py

Answer 3

This might help:

from django.core.management.base import BaseCommand
from django.db import connections


class Command(BaseCommand):

    def handle(self, database="default", *args, **options):

        cursor = connections[database].cursor()

        cursor.execute("SHOW TABLE STATUS")

        for row in cursor.fetchall():
            if row[1] != "InnoDB":
                print "Converting %s" % row[0],
                print cursor.execute("ALTER TABLE %s ENGINE=INNODB" % row[0])

Add that to your app under the folders management/commands/ Then you can convert all your tables with a manage.py command:

python manage.py convert_to_innodb

Answer 4

This really has nothing to do with Django. It's entirely a MySQL thing, and there's documentation on just this type of thing directly from them: http://dev.mysql.com/doc/refman/5.5/en/converting-tables-to-innodb.html