Add index to file_store on ci_job_artifacts

changelogs/unreleased/45476-geo-statement-timeout-counting-local-job-artifacts.yml

+---
+title: Add index to file_store on ci_job_artifacts
+merge_request: 18444
+author:
+type: performance

db/migrate/20180418053107_add_index_to_ci_job_artifacts_file_store.rb

+class AddIndexToCiJobArtifactsFileStore < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_job_artifacts, :file_store
+  end
+
+  def down
+    remove_index :ci_job_artifacts, :file_store if index_exists?(:ci_job_artifacts, :file_store)
+  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: 20180405142733) do
+ActiveRecord::Schema.define(version: 20180418053107) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -367,6 +367,7 @@ ActiveRecord::Schema.define(version: 20180405142733) do
   end
 
   add_index "ci_job_artifacts", ["expire_at", "job_id"], name: "index_ci_job_artifacts_on_expire_at_and_job_id", using: :btree
+  add_index "ci_job_artifacts", ["file_store"], name: "index_ci_job_artifacts_on_file_store", using: :btree
   add_index "ci_job_artifacts", ["job_id", "file_type"], name: "index_ci_job_artifacts_on_job_id_and_file_type", unique: true, using: :btree
   add_index "ci_job_artifacts", ["project_id"], name: "index_ci_job_artifacts_on_project_id", using: :btree