[Screencast] ActiveRecord Migrations

Learning Ruby
1

This episode covers different tips and tricks around database migration files. https://www.driftingruby.com/episodes/activerecord-migrations

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2

Thanks.
A good new option to be used in migration for adding index to avoid locking is:

class AddMigrationForPerformanceExample < ActiveRecord::Migration[5.0]

  disable_ddl_transaction!

  def change
    add_index(
      :table,
      [
        :col_1,
        :col_2,
      ],

      # Prevent locking thus downtime
      # Requires `disable_ddl_transaction!`
      # https://robots.thoughtbot.com/how-to-create-postgres-indexes-concurrently-in
      algorithm: :concurrently,
    )
  end
end
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