Production Notes

Database engines and migrations

The original tables were created on an older version of MySQL using MyISAM as the database engine. There's a newer version of MySQL on our AWS environment, one that supports InnoDB, but we can't create foreign key relationships between MyISAM and InnoDB tables. This means that we need to create new tables with MyISAM.

We can run South per usual. You do need to take two extra steps when running migrations that create tables. There's a line in settings/prod.py, under DATABASE. It's normally commented-out.

    # 'STORAGE_ENGINE': 'MYISAM',	 # Uncomment this when creating new tables	  

To create new tables:

1. Uncomment that line under settings/prod.py.

2. Run your migrations.

3. Comment-out the line.

We can probably leave that line in all of the time, but we comment it out because of a possible performance hit (the docs are silent on this issue). Eventually we'll want to move everything over to InnoDB.

See:

• Django database docs
• Django database docs - storage engines
• Explicitly set MySQL table storage engine using South and Django
• South settings docs