Action Scheduler 120 tasks pending but list is empty

The Action Scheduler does not show any actions in the list, the list is empty. But it shows “All (782) | Complete (662) | Pending (120)”

The debug.log file grows by 100MB per week with repeating entries like the following. A problem I heard from other users but there was no fix so far is that tables with a prefix “a.” can’t be found – of course, because they don’t exist.

How to get rid off these errors and fix the Action Scheduler?

Reinstalling Action Scheduler did not change anything.

debug.log:
======================
[16-Mar-2020 19:36:27 UTC] WordPress database error Deadlock found when trying to get lock; try restarting transaction for query UPDATE wpsf_actionscheduler_actions SET claim_id = 0 WHERE claim_id = 11631941 made by do_action(‘wp_ajax_nopriv_as_async_request_queue_runner’), WP_Hook->do_action, WP_Hook->apply_filters, WP_Async_Request->maybe_handle, ActionScheduler_AsyncRequest_QueueRunner->handle, do_action(‘action_scheduler_run_queue’), WP_Hook->do_action, WP_Hook->apply_filters, ActionScheduler_QueueRunner->run, ActionScheduler_QueueRunner->do_batch, ActionScheduler_HybridStore->release_claim, ActionScheduler_DBStore->release_claim
[16-Mar-2020 19:36:28 UTC] PHP Notice: Undefined property: wpdb::$actionscheduler_actions in /home/univer73/public_html/universalsolder/wp-includes/wp-db.php on line 659
[16-Mar-2020 19:36:28 UTC] WordPress database error Table ‘univer73_wp691.a’ doesn’t exist for query SELECT a.action_id FROM a WHERE a.hook=’action_scheduler/migration_hook’ AND a.status=’in-progress’ ORDER BY scheduled_date_gmt DESC LIMIT 1 made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->is_migration_scheduled, as_next_scheduled_action, ActionScheduler_HybridStore->find_action, ActionScheduler_DBStore->find_action
[16-Mar-2020 19:36:28 UTC] WordPress database error Table ‘univer73_wp691.a’ doesn’t exist for query SELECT a.action_id FROM a WHERE a.hook=’action_scheduler/migration_hook’ AND a.status=’pending’ ORDER BY scheduled_date_gmt ASC LIMIT 1 made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->is_migration_scheduled, as_next_scheduled_action, ActionScheduler_HybridStore->find_action, ActionScheduler_DBStore->find_action
[16-Mar-2020 19:36:28 UTC] WordPress database error Table ‘univer73_wp691.a’ doesn’t exist for query SELECT a.action_id FROM a WHERE a.hook=’action_scheduler/migration_hook’ AND a.status=’in-progress’ ORDER BY scheduled_date_gmt DESC LIMIT 1 made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->schedule_migration, as_next_scheduled_action, ActionScheduler_HybridStore->find_action, ActionScheduler_DBStore->find_action
[16-Mar-2020 19:36:28 UTC] WordPress database error Table ‘univer73_wp691.a’ doesn’t exist for query SELECT a.action_id FROM a WHERE a.hook=’action_scheduler/migration_hook’ AND a.status=’pending’ ORDER BY scheduled_date_gmt ASC LIMIT 1 made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->schedule_migration, as_next_scheduled_action, ActionScheduler_HybridStore->find_action, ActionScheduler_DBStore->find_action
[16-Mar-2020 19:36:28 UTC] PHP Notice: Undefined property: wpdb::$actionscheduler_groups in /home/univer73/public_html/universalsolder/wp-includes/wp-db.php on line 659
[16-Mar-2020 19:36:28 UTC] WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘WHERE slug=’action-scheduler-migration” at line 1 for query SELECT group_id FROM WHERE slug=’action-scheduler-migration’ made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->schedule_migration, as_schedule_single_action, ActionScheduler_ActionFactory->single, ActionScheduler_ActionFactory->store, ActionScheduler_HybridStore->save_action, ActionScheduler_DBStoreMigrator->save_action, ActionScheduler_DBStore->save_action, ActionScheduler_DBStore->get_group_id
[16-Mar-2020 19:36:28 UTC] WordPress database error Incorrect table name ” for query SHOW FULL COLUMNS FROM made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->schedule_migration, as_schedule_single_action, ActionScheduler_ActionFactory->single, ActionScheduler_ActionFactory->store, ActionScheduler_HybridStore->save_action, ActionScheduler_DBStoreMigrator->save_action, ActionScheduler_DBStore->save_action, ActionScheduler_DBStore->get_group_id, ActionScheduler_DBStore->create_group
[16-Mar-2020 19:36:28 UTC] PHP Notice: Undefined property: wpdb::$actionscheduler_actions in /home/univer73/public_html/universalsolder/wp-includes/wp-db.php on line 659
[16-Mar-2020 19:36:28 UTC] WordPress database error Incorrect table name ” for query SHOW FULL COLUMNS FROM made by shutdown_action_hook, do_action(‘shutdown’), WP_Hook->do_action, WP_Hook->apply_filters, Action_Scheduler\Migration\Controller->schedule_migration, Action_Scheduler\Migration\Scheduler->schedule_migration, as_schedule_single_action, ActionScheduler_ActionFactory->single, ActionScheduler_ActionFactory->store, ActionScheduler_HybridStore->save_action, ActionScheduler_DBStoreMigrator->save_action, ActionScheduler_DBStore->save_action
[16-Mar-2020 19:36:28 UTC] PHP Fatal error: Uncaught RuntimeException: Error saving action: Error saving action: Incorrect table name ” in /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/classes/migration/ActionScheduler_DBStoreMigrator.php:44
Stack trace:
#0 /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/classes/data-stores/ActionScheduler_HybridStore.php(225): ActionScheduler_DBStoreMigrator->save_action(Object(ActionScheduler_Action), NULL)
#1 /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/classes/ActionScheduler_ActionFactory.php(177): ActionScheduler_HybridStore->save_action(Object(ActionScheduler_Action))
#2 /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/classes/ActionScheduler_ActionFactory.php(84): ActionScheduler_ActionFactory->store(Object(ActionScheduler_Action))
#3 /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/functions.php(30): ActionScheduler_Act in /home/univer73/public_html/universalsolder/wp-content/plugins/action-scheduler-master/classes/migration/ActionScheduler_DBStoreMigrator.php on line 44
[16-Mar-2020 19:36:28 UTC] WordPress database error Deadlock found when trying to get lock; try restarting transaction for query UPDATE wpsf_actionscheduler_actions SET claim_id = 0 WHERE claim_id = 11632106 made by do_action_ref_array(‘action_scheduler_run_queue’), WP_Hook->do_action, WP_Hook->apply_filters, ActionScheduler_QueueRunner->run, ActionScheduler_QueueRunner->do_batch, ActionScheduler_HybridStore->release_claim, ActionScheduler_DBStore->release_claim

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