use lodash.once instead of memoize, and skip unnecessary PK index

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend-tasks/migrations/20210928160613_init.js

@@ -50,7 +50,6 @@ exports.up = async function up(knex) {
       .dateTime('current_run_expires_at')
       .nullable()
       .comment('The time that the current task run will time out');
-    table.index(['id'], 'backstage_backend_tasks__tasks__id_idx');
   });
 };
 
@@ -61,8 +60,5 @@ exports.down = async function down(knex) {
   //
   // tasks
   //
-  await knex.schema.alterTable('backstage_backend_tasks__tasks', table => {
-    table.dropIndex([], 'backstage_backend_tasks__tasks__id_idx');
-  });
   await knex.schema.dropTable('backstage_backend_tasks__tasks');
 };

packages/backend-tasks/src/tasks/TaskScheduler.ts

@@ -16,7 +16,7 @@
 
 import { DatabaseManager, getRootLogger } from '@backstage/backend-common';
 import { Config } from '@backstage/config';
-import { memoize } from 'lodash';
+import { once } from 'lodash';
 import { Duration } from 'luxon';
 import { Logger } from 'winston';
 import { migrateBackendTasks } from '../database/migrateBackendTasks';
@@ -57,7 +57,7 @@ export class TaskScheduler {
    * @returns A {@link PluginTaskScheduler} instance
    */
   forPlugin(pluginId: string): PluginTaskScheduler {
-    const databaseFactory = memoize(async () => {
+    const databaseFactory = once(async () => {
       const knex = await this.databaseManager.forPlugin(pluginId).getClient();
 
       await migrateBackendTasks(knex);