mastodon/db/migrate/20171125185353_add_index_reblog_of_id_and_account_to_statuses.rb

class AddIndexReblogOfIdAndAccountToStatuses < ActiveRecord::Migration[5.1]
  disable_ddl_transaction!

  def change
    add_index :statuses, [:reblog_of_id, :account_id], algorithm: :concurrently
  end
end
Merge indexes for reblog on statuses table (#5831) We added an index for `[account_id, reblog_of_id]`, but we already have a similar index for `reblog_of_id`. Those index will be bigger according to statuses count. For example, `reblog_of_id` index uses 800MB for 10GB statuses table. So this patch swaps indexed columns like `[reblog_of_id, account_id]`, then it will covers both usage with single index. Since those index creation may take a while, I've also disabled previous index creation. 2017-11-27 20:22:27 +01:00			`class AddIndexReblogOfIdAndAccountToStatuses < ActiveRecord::Migration[5.1]`
			`disable_ddl_transaction!`

			`def change`
			`add_index :statuses, [:reblog_of_id, :account_id], algorithm: :concurrently`
			`end`
			`end`