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| -rw-r--r-- | doc/development/migration_style_guide.md | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/doc/development/migration_style_guide.md b/doc/development/migration_style_guide.md index 02e024ca15a..8a7547e5322 100644 --- a/doc/development/migration_style_guide.md +++ b/doc/development/migration_style_guide.md @@ -34,6 +34,15 @@ First, you need to provide information on whether the migration can be applied: 3. online with errors on new instances while migrating 4. offline (needs to happen without app servers to prevent db corruption) +For example: + +``` +# rubocop:disable all +# Migration type: online without errors (works on previous version and new one) +class MyMigration < ActiveRecord::Migration +... +``` + It is always preferable to have a migration run online. If you expect the migration to take particularly long (for instance, if it loops through all notes), this is valuable information to add. @@ -48,7 +57,6 @@ be possible to downgrade in case of a vulnerability or bugs. In your migration, add a comment describing how the reversibility of the migration was tested. - ## Removing indices If you need to remove index, please add a condition like in following example: @@ -70,6 +78,7 @@ so: ``` class MyMigration < ActiveRecord::Migration + include Gitlab::Database::MigrationHelpers disable_ddl_transaction! def change @@ -90,8 +99,11 @@ value of `10` you'd write the following: ``` class MyMigration < ActiveRecord::Migration + include Gitlab::Database::MigrationHelpers + disable_ddl_transaction! + def up - add_column_with_default(:projects, :foo, :integer, 10) + add_column_with_default(:projects, :foo, :integer, default: 10) end def down |