Reorganize indexes for the "deployments" table

This removes the need for a default scope that adds a "WHERE project_id
= X" clause. This commit also includes an additional index for
Environment#last_deployment, ensuring this query uses just an index scan
instead of also applying a Filter.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36877
parent 0223d84e
......@@ -6,9 +6,7 @@ class Environment < ActiveRecord::Base
belongs_to :project, required: true, validate: true
has_many :deployments,
-> (env) { where(project_id: env.project_id) },
dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
has_many :deployments, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
has_one :last_deployment, -> { order('deployments.id DESC') }, class_name: 'Deployment'
......
---
title: Reorganize indexes for the "deployments" table
merge_request:
author:
type: other
# See http://doc.gitlab.com/ce/development/migration_style_guide.html
# for more information on how to write migrations for GitLab.
class ReorganizeDeploymentsIndexes < ActiveRecord::Migration
include Gitlab::Database::MigrationHelpers
DOWNTIME = false
disable_ddl_transaction!
def up
add_index_if_not_exists :deployments, [:environment_id, :iid, :project_id]
remove_index_if_exists :deployments, [:project_id, :environment_id, :iid]
end
def down
add_index_if_not_exists :deployments, [:project_id, :environment_id, :iid]
remove_index_if_exists :deployments, [:environment_id, :iid, :project_id]
end
def add_index_if_not_exists(table, columns)
add_concurrent_index(table, columns) unless index_exists?(table, columns)
end
def remove_index_if_exists(table, columns)
remove_concurrent_index(table, columns) if index_exists?(table, columns)
end
end
# See http://doc.gitlab.com/ce/development/migration_style_guide.html
# for more information on how to write migrations for GitLab.
class AddDeploymentsIndexForLastDeployment < ActiveRecord::Migration
include Gitlab::Database::MigrationHelpers
# Set this constant to true if this migration requires downtime.
DOWNTIME = false
disable_ddl_transaction!
TO_INDEX = [:deployments, %i[environment_id id]].freeze
def up
add_concurrent_index(*TO_INDEX)
end
def down
remove_concurrent_index(*TO_INDEX)
end
end
......@@ -11,7 +11,7 @@
#
# It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema.define(version: 20170914135630) do
ActiveRecord::Schema.define(version: 20170918223303) do
# These are extensions that must be enabled in order to support this database
enable_extension "plpgsql"
......@@ -506,7 +506,8 @@ ActiveRecord::Schema.define(version: 20170914135630) do
end
add_index "deployments", ["created_at"], name: "index_deployments_on_created_at", using: :btree
add_index "deployments", ["project_id", "environment_id", "iid"], name: "index_deployments_on_project_id_and_environment_id_and_iid", using: :btree
add_index "deployments", ["environment_id", "id"], name: "index_deployments_on_environment_id_and_id", using: :btree
add_index "deployments", ["environment_id", "iid", "project_id"], name: "index_deployments_on_environment_id_and_iid_and_project_id", using: :btree
add_index "deployments", ["project_id", "iid"], name: "index_deployments_on_project_id_and_iid", unique: true, using: :btree
create_table "emails", force: :cascade do |t|
......
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