Add multiple assignees migration and table population

This will be further required for supporting multi-assignees MRs

3 files changed, 56 insertions, 1 deletions

diff --git a/db/migrate/20190315191339_create_merge_request_assignees_table.rb b/db/migrate/20190315191339_create_merge_request_assignees_table.rb
new file mode 100644
index 00000000000..6fc4463f281
--- /dev/null
+++ b/db/migrate/20190315191339_create_merge_request_assignees_table.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class CreateMergeRequestAssigneesTable < ActiveRecord::Migration[5.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  INDEX_NAME = 'index_merge_request_assignees_on_merge_request_id_and_user_id'
+
+  def up
+    create_table :merge_request_assignees do |t|
+      t.references :user, foreign_key: { on_delete: :cascade }, index: true, null: false
+      t.references :merge_request, foreign_key: { on_delete: :cascade }, null: false
+    end
+
+    add_index :merge_request_assignees, [:merge_request_id, :user_id], unique: true, name: INDEX_NAME
+  end
+
+  def down
+    drop_table :merge_request_assignees
+  end
+end
diff --git a/db/post_migrate/20190322132835_schedule_populate_merge_request_assignees_table.rb b/db/post_migrate/20190322132835_schedule_populate_merge_request_assignees_table.rb
new file mode 100644
index 00000000000..1ecb38e1a86
--- /dev/null
+++ b/db/post_migrate/20190322132835_schedule_populate_merge_request_assignees_table.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class SchedulePopulateMergeRequestAssigneesTable < ActiveRecord::Migration[5.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 10_000
+  MIGRATION = 'PopulateMergeRequestAssigneesTable'
+  DELAY_INTERVAL = 8.minutes.to_i
+
+  disable_ddl_transaction!
+
+  def up
+    say 'Scheduling `PopulateMergeRequestAssigneesTable` jobs'
+    # We currently have ~4_500_000 merge request records on GitLab.com.
+    # This means it'll schedule ~450 jobs (10k MRs each) with a 8 minutes gap,
+    # so this should take ~60 hours for all background migrations to complete.
+    queue_background_migration_jobs_by_range_at_intervals(MergeRequest, MIGRATION, DELAY_INTERVAL, batch_size: BATCH_SIZE)
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index dda0445e3f2..0c997f3b8a2 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20190301182457) do
+ActiveRecord::Schema.define(version: 20190322132835) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -1201,6 +1201,14 @@ ActiveRecord::Schema.define(version: 20190301182457) do
     t.index ["user_id"], name: "index_members_on_user_id", using: :btree
   end
 
+  create_table "merge_request_assignees", force: :cascade do |t|
+    t.integer "user_id", null: false
+    t.integer "merge_request_id", null: false
+    t.index ["merge_request_id", "user_id"], name: "index_merge_request_assignees_on_merge_request_id_and_user_id", unique: true, using: :btree
+    t.index ["merge_request_id"], name: "index_merge_request_assignees_on_merge_request_id", using: :btree
+    t.index ["user_id"], name: "index_merge_request_assignees_on_user_id", using: :btree
+  end
+
   create_table "merge_request_diff_commits", id: false, force: :cascade do |t|
     t.datetime_with_timezone "authored_date"
     t.datetime_with_timezone "committed_date"
@@ -2454,6 +2462,8 @@ ActiveRecord::Schema.define(version: 20190301182457) do
   add_foreign_key "lists", "boards", name: "fk_0d3f677137", on_delete: :cascade
   add_foreign_key "lists", "labels", name: "fk_7a5553d60f", on_delete: :cascade
   add_foreign_key "members", "users", name: "fk_2e88fb7ce9", on_delete: :cascade
+  add_foreign_key "merge_request_assignees", "merge_requests", on_delete: :cascade
+  add_foreign_key "merge_request_assignees", "users", on_delete: :cascade
   add_foreign_key "merge_request_diff_commits", "merge_request_diffs", on_delete: :cascade
   add_foreign_key "merge_request_diff_files", "merge_request_diffs", on_delete: :cascade
   add_foreign_key "merge_request_diffs", "merge_requests", name: "fk_8483f3258f", on_delete: :cascade