Remove code hotspots tables

- Using `with_lock_retries` helper method.
- Fix duration conversion within `with_lock_retries`.

changelogs/unreleased/198313-remove-code-hotspots-tables.yml

+---
+title: Remove unused Code Hotspots database tables
+merge_request: 23590
+author:
+type: other

db/migrate/20200123090839_remove_analytics_repository_table_fks_on_projects.rb

+# frozen_string_literal: true
+
+class RemoveAnalyticsRepositoryTableFksOnProjects < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    with_lock_retries do
+      # Requires ExclusiveLock on all tables. analytics_* tables are empty
+      remove_foreign_key :analytics_repository_files, :projects
+      remove_foreign_key :analytics_repository_file_edits, :projects
+      remove_foreign_key :analytics_repository_file_commits, :projects
+    end
+  end
+
+  def down
+    with_lock_retries do
+      # rubocop:disable Migration/AddConcurrentForeignKey
+      add_foreign_key :analytics_repository_files, :projects, on_delete: :cascade
+      add_foreign_key :analytics_repository_file_edits, :projects, on_delete: :cascade
+      add_foreign_key :analytics_repository_file_commits, :projects, on_delete: :cascade
+      # rubocop:enable Migration/AddConcurrentForeignKey
+    end
+  end
+end

db/migrate/20200123091422_remove_analytics_repository_files_fk_on_other_analytics_tables.rb

+# frozen_string_literal: true
+
+class RemoveAnalyticsRepositoryFilesFkOnOtherAnalyticsTables < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    with_lock_retries do
+      # Requires ExclusiveLock on all tables. analytics_* tables are empty
+      remove_foreign_key :analytics_repository_file_edits, :analytics_repository_files
+      remove_foreign_key :analytics_repository_file_commits, :analytics_repository_files
+    end
+  end
+
+  def down
+    with_lock_retries do
+      # rubocop:disable Migration/AddConcurrentForeignKey
+      add_foreign_key :analytics_repository_file_edits, :analytics_repository_files, on_delete: :cascade
+      add_foreign_key :analytics_repository_file_commits, :analytics_repository_files, on_delete: :cascade
+      # rubocop:enable Migration/AddConcurrentForeignKey
+    end
+  end
+end

db/migrate/20200123091622_drop_analytics_repository_files_table.rb

+# frozen_string_literal: true
+
+class DropAnalyticsRepositoryFilesTable < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    # Requires ExclusiveLock on the table. Not in use, no records, no FKs.
+    drop_table :analytics_repository_files
+  end
+
+  def down
+    create_table :analytics_repository_files do |t|
+      t.bigint :project_id, null: false
+      t.string :file_path, limit: 4096, null: false
+    end
+
+    add_index :analytics_repository_files, [:project_id, :file_path], unique: true
+  end
+end

db/migrate/20200123091734_drop_analytics_repository_file_commits_table.rb

+# frozen_string_literal: true
+
+class DropAnalyticsRepositoryFileCommitsTable < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    # Requires ExclusiveLock on the table. Not in use, no records, no FKs.
+    drop_table :analytics_repository_file_commits
+  end
+
+  def down
+    create_table :analytics_repository_file_commits do |t|
+      t.bigint :analytics_repository_file_id, null: false
+      t.index :analytics_repository_file_id, name: 'index_analytics_repository_file_commits_file_id'
+      t.bigint :project_id, null: false
+      t.date :committed_date, null: false
+      t.integer :commit_count, limit: 2, null: false
+    end
+
+    add_index :analytics_repository_file_commits,
+      [:project_id, :committed_date, :analytics_repository_file_id],
+      name: 'index_file_commits_on_committed_date_file_id_and_project_id',
+      unique: true
+  end
+end

db/migrate/20200123091854_drop_analytics_repository_file_edits_table.rb

+# frozen_string_literal: true
+
+class DropAnalyticsRepositoryFileEditsTable < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    # Requires ExclusiveLock on the table. Not in use, no records, no FKs.
+    drop_table :analytics_repository_file_edits
+  end
+
+  def down
+    create_table :analytics_repository_file_edits do |t|
+      t.bigint :project_id, null: false
+      t.index :project_id
+      t.bigint :analytics_repository_file_id, null: false
+      t.date :committed_date, null: false
+      t.integer :num_edits, null: false, default: 0
+    end
+
+    add_index :analytics_repository_file_edits,
+      [:analytics_repository_file_id, :committed_date, :project_id],
+      name: 'index_file_edits_on_committed_date_file_id_and_project_id',
+      unique: true
+  end
+end

db/schema.rb

@@ -94,30 +94,6 @@ ActiveRecord::Schema.define(version: 2020_01_27_090233) do
     t.index ["project_id"], name: "analytics_repository_languages_on_project_id"
   end
 
-  create_table "analytics_repository_file_commits", force: :cascade do |t|
-    t.bigint "analytics_repository_file_id", null: false
-    t.bigint "project_id", null: false
-    t.date "committed_date", null: false
-    t.integer "commit_count", limit: 2, null: false
-    t.index ["analytics_repository_file_id"], name: "index_analytics_repository_file_commits_file_id"
-    t.index ["project_id", "committed_date", "analytics_repository_file_id"], name: "index_file_commits_on_committed_date_file_id_and_project_id", unique: true
-  end
-
-  create_table "analytics_repository_file_edits", force: :cascade do |t|
-    t.bigint "project_id", null: false
-    t.bigint "analytics_repository_file_id", null: false
-    t.date "committed_date", null: false
-    t.integer "num_edits", default: 0, null: false
-    t.index ["analytics_repository_file_id", "committed_date", "project_id"], name: "index_file_edits_on_committed_date_file_id_and_project_id", unique: true
-    t.index ["project_id"], name: "index_analytics_repository_file_edits_on_project_id"
-  end
-
-  create_table "analytics_repository_files", force: :cascade do |t|
-    t.bigint "project_id", null: false
-    t.string "file_path", limit: 4096, null: false
-    t.index ["project_id", "file_path"], name: "index_analytics_repository_files_on_project_id_and_file_path", unique: true
-  end
-
   create_table "appearances", id: :serial, force: :cascade do |t|
     t.string "title", null: false
     t.text "description", null: false
@@ -4476,11 +4452,6 @@ ActiveRecord::Schema.define(version: 2020_01_27_090233) do
   add_foreign_key "analytics_cycle_analytics_project_stages", "projects", on_delete: :cascade
   add_foreign_key "analytics_language_trend_repository_languages", "programming_languages", on_delete: :cascade
   add_foreign_key "analytics_language_trend_repository_languages", "projects", on_delete: :cascade
-  add_foreign_key "analytics_repository_file_commits", "analytics_repository_files", on_delete: :cascade
-  add_foreign_key "analytics_repository_file_commits", "projects", on_delete: :cascade
-  add_foreign_key "analytics_repository_file_edits", "analytics_repository_files", on_delete: :cascade
-  add_foreign_key "analytics_repository_file_edits", "projects", on_delete: :cascade
-  add_foreign_key "analytics_repository_files", "projects", on_delete: :cascade
   add_foreign_key "application_settings", "namespaces", column: "custom_project_templates_group_id", on_delete: :nullify
   add_foreign_key "application_settings", "namespaces", column: "instance_administrators_group_id", name: "fk_e8a145f3a7", on_delete: :nullify
   add_foreign_key "application_settings", "projects", column: "file_template_project_id", name: "fk_ec757bd087", on_delete: :nullify

lib/gitlab/database/with_lock_retries.rb

@@ -147,11 +147,11 @@ module Gitlab
       end
 
       def current_lock_timeout_in_ms
-        timing_configuration[current_iteration - 1][0].in_milliseconds
+        Integer(timing_configuration[current_iteration - 1][0].in_milliseconds)
       end
 
       def current_sleep_time_in_seconds
-        timing_configuration[current_iteration - 1][1].to_i
+        timing_configuration[current_iteration - 1][1].to_f
       end
     end
   end

spec/lib/gitlab/database/with_lock_retries_spec.rb

@@ -128,4 +128,23 @@ describe Gitlab::Database::WithLockRetries do
       end
     end
   end
+
+  context 'casting durations correctly' do
+    let(:timing_configuration) { [[0.015.seconds, 0.025.seconds], [0.015.seconds, 0.025.seconds]] } # 15ms, 25ms
+
+    it 'executes `SET LOCAL lock_timeout` using the configured timeout value in milliseconds' do
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("SAVEPOINT active_record_1").and_call_original
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("SET LOCAL lock_timeout TO '15ms'").and_call_original
+      expect(ActiveRecord::Base.connection).to receive(:execute).with("RELEASE SAVEPOINT active_record_1").and_call_original
+
+      subject.run { }
+    end
+
+    it 'calls `sleep` after the first iteration fails, using the configured sleep time' do
+      expect(subject).to receive(:run_block_with_transaction).and_raise(ActiveRecord::LockWaitTimeout).twice
+      expect(subject).to receive(:sleep).with(0.025)
+
+      subject.run { }
+    end
+  end
 end