Remove trigram indexes for "ci_runners"

CHANGELOG

@@ -36,6 +36,7 @@ v 8.11.0 (unreleased)
   - Retrieve rendered HTML from cache in one request
   - Fix renaming repository when name contains invalid chararacters under project settings
   - Upgrade Grape from 0.13.0 to 0.15.0. !4601
+  - Trigram indexes for the "ci_runners" table have been removed to speed up UPDATE queries
   - Fix devise deprecation warnings.
   - Update version_sorter and use new interface for faster tag sorting
   - Optimize checking if a user has read access to a list of issues !5370

db/migrate/20160810102349_remove_ci_runner_trigram_indexes.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveCiRunnerTrigramIndexes < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  # Disabled for the "down" method so the indexes can be re-created concurrently.
+  disable_ddl_transaction!
+
+  def up
+    return unless Gitlab::Database.postgresql?
+
+    transaction do
+      execute 'DROP INDEX IF EXISTS index_ci_runners_on_token_trigram;'
+      execute 'DROP INDEX IF EXISTS index_ci_runners_on_description_trigram;'
+    end
+  end
+
+  def down
+    return unless Gitlab::Database.postgresql?
+
+    execute 'CREATE INDEX CONCURRENTLY index_ci_runners_on_token_trigram ON ci_runners USING gin(token gin_trgm_ops);'
+    execute 'CREATE INDEX CONCURRENTLY index_ci_runners_on_description_trigram ON ci_runners USING gin(description gin_trgm_ops);'
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160804150737) do
+ActiveRecord::Schema.define(version: 20160810102349) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -301,10 +301,8 @@ ActiveRecord::Schema.define(version: 20160804150737) do
     t.boolean  "locked",       default: false, null: false
   end
 
-  add_index "ci_runners", ["description"], name: "index_ci_runners_on_description_trigram", using: :gin, opclasses: {"description"=>"gin_trgm_ops"}
   add_index "ci_runners", ["locked"], name: "index_ci_runners_on_locked", using: :btree
   add_index "ci_runners", ["token"], name: "index_ci_runners_on_token", using: :btree
-  add_index "ci_runners", ["token"], name: "index_ci_runners_on_token_trigram", using: :gin, opclasses: {"token"=>"gin_trgm_ops"}
 
   create_table "ci_services", force: :cascade do |t|
     t.string   "type"