Fix slow query of federated timeline (#12886)

db/migrate/20200119112504_add_public_index_to_statuses.rb

@@ -0,0 +1,11 @@
+class AddPublicIndexToStatuses < ActiveRecord::Migration[5.2]
+  disable_ddl_transaction!
+
+  def up
+    add_index :statuses, [:id, :account_id], name: :index_statuses_public_20200119, algorithm: :concurrently, order: { id: :desc }, where: 'deleted_at IS NULL AND visibility = 0 AND reblog_of_id IS NULL AND ((NOT reply) OR (in_reply_to_account_id = account_id))'
+  end
+
+  def down
+    remove_index :statuses, name: :index_statuses_public_20200119
+  end
+end

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: 2019_12_12_003415) do
+ActiveRecord::Schema.define(version: 2020_01_19_112504) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -690,6 +690,7 @@ ActiveRecord::Schema.define(version: 2019_12_12_003415) do
     t.datetime "deleted_at"
     t.index ["account_id", "id", "visibility", "updated_at"], name: "index_statuses_20190820", order: { id: :desc }, where: "(deleted_at IS NULL)"
     t.index ["id", "account_id"], name: "index_statuses_local_20190824", order: { id: :desc }, where: "((local OR (uri IS NULL)) AND (deleted_at IS NULL) AND (visibility = 0) AND (reblog_of_id IS NULL) AND ((NOT reply) OR (in_reply_to_account_id = account_id)))"
+    t.index ["id", "account_id"], name: "index_statuses_public_20200119", order: { id: :desc }, where: "((deleted_at IS NULL) AND (visibility = 0) AND (reblog_of_id IS NULL) AND ((NOT reply) OR (in_reply_to_account_id = account_id)))"
     t.index ["in_reply_to_account_id"], name: "index_statuses_on_in_reply_to_account_id"
     t.index ["in_reply_to_id"], name: "index_statuses_on_in_reply_to_id"
     t.index ["reblog_of_id", "account_id"], name: "index_statuses_on_reblog_of_id_and_account_id"