diff options
Diffstat (limited to 'lib/gitlab/database/migration_helpers.rb')
| -rw-r--r-- | lib/gitlab/database/migration_helpers.rb | 121 |
1 files changed, 111 insertions, 10 deletions
diff --git a/lib/gitlab/database/migration_helpers.rb b/lib/gitlab/database/migration_helpers.rb index 3f65bc912de..33171f83692 100644 --- a/lib/gitlab/database/migration_helpers.rb +++ b/lib/gitlab/database/migration_helpers.rb @@ -385,10 +385,27 @@ module Gitlab # necessary since we copy over old values further down. change_column_default(table, new, old_col.default) if old_col.default - trigger_name = rename_trigger_name(table, old, new) + install_rename_triggers(table, old, new) + + update_column_in_batches(table, new, Arel::Table.new(table)[old]) + + change_column_null(table, new, false) unless old_col.null + + copy_indexes(table, old, new) + copy_foreign_keys(table, old, new) + end + + # Installs triggers in a table that keep a new column in sync with an old + # one. + # + # table - The name of the table to install the trigger in. + # old_column - The name of the old column. + # new_column - The name of the new column. + def install_rename_triggers(table, old_column, new_column) + trigger_name = rename_trigger_name(table, old_column, new_column) quoted_table = quote_table_name(table) - quoted_old = quote_column_name(old) - quoted_new = quote_column_name(new) + quoted_old = quote_column_name(old_column) + quoted_new = quote_column_name(new_column) if Database.postgresql? install_rename_triggers_for_postgresql(trigger_name, quoted_table, @@ -397,13 +414,6 @@ module Gitlab install_rename_triggers_for_mysql(trigger_name, quoted_table, quoted_old, quoted_new) end - - update_column_in_batches(table, new, Arel::Table.new(table)[old]) - - change_column_null(table, new, false) unless old_col.null - - copy_indexes(table, old, new) - copy_foreign_keys(table, old, new) end # Changes the type of a column concurrently. @@ -455,6 +465,97 @@ module Gitlab remove_column(table, old) end + # Changes the column type of a table using a background migration. + # + # Because this method uses a background migration it's more suitable for + # large tables. For small tables it's better to use + # `change_column_type_concurrently` since it can complete its work in a + # much shorter amount of time and doesn't rely on Sidekiq. + # + # Example usage: + # + # class Issue < ActiveRecord::Base + # self.table_name = 'issues' + # + # include EachBatch + # + # def self.to_migrate + # where('closed_at IS NOT NULL') + # end + # end + # + # change_column_type_using_background_migration( + # Issue.to_migrate, + # :closed_at, + # :datetime_with_timezone + # ) + # + # Reverting a migration like this is done exactly the same way, just with + # a different type to migrate to (e.g. `:datetime` in the above example). + # + # relation - An ActiveRecord relation to use for scheduling jobs and + # figuring out what table we're modifying. This relation _must_ + # have the EachBatch module included. + # + # column - The name of the column for which the type will be changed. + # + # new_type - The new type of the column. + # + # batch_size - The number of rows to schedule in a single background + # migration. + # + # interval - The time interval between every background migration. + def change_column_type_using_background_migration( + relation, + column, + new_type, + batch_size: 10_000, + interval: 10.minutes + ) + unless relation.model < EachBatch + raise TypeError, 'The relation must include the EachBatch module' + end + + temp_column = "#{column}_for_type_change" + table = relation.table_name + max_index = 0 + + add_column(table, temp_column, new_type) + install_rename_triggers(table, column, temp_column) + + # Schedule the jobs that will copy the data from the old column to the + # new one. + relation.each_batch(of: batch_size) do |batch, index| + start_id, end_id = batch.pluck('MIN(id), MAX(id)').first + max_index = index + + BackgroundMigrationWorker.perform_in( + index * interval, + 'CopyColumn', + [table, column, temp_column, start_id, end_id] + ) + end + + # Schedule the renaming of the column to happen (initially) 1 hour after + # the last batch finished. + BackgroundMigrationWorker.perform_in( + (max_index * interval) + 1.hour, + 'CleanupConcurrentTypeChange', + [table, column, temp_column] + ) + + if perform_background_migration_inline? + # To ensure the schema is up to date immediately we perform the + # migration inline in dev / test environments. + Gitlab::BackgroundMigration.steal('CopyColumn') + Gitlab::BackgroundMigration.steal('CleanupConcurrentTypeChange') + end + end + + def perform_background_migration_inline? + Rails.env.test? || Rails.env.development? + end + # Performs a concurrent column rename when using PostgreSQL. def install_rename_triggers_for_postgresql(trigger, table, old, new) execute <<-EOF.strip_heredoc |