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DB migrations

View original Gist on GitHub

DB migrations.md

Renaming or changing the type of a column

• Create a new column
• Write to both columns
• Backfill data from the old column to the new column
• Move reads from the old column to the new column
• Stop writing to the old column
• Drop the old column

Renaming a table

• Create a new table
• Write to both tables
• Backfill data from the old table to new table
• Move reads from the old table to the new table
• Stop writing to the old table
• Drop the old table

Adding a column with a default value

• Add the column without a default value
• Commit the transaction
• Backfill the column
• Add the default value