Link check gets stuck

@wpmudev-support8

Although it is still running, the first error appears in the debug log and it seems related:

[redacted]

[09-Apr-2021 07:42:38 UTC] PHP Warning:  mysqli_query(): (HY001/1038): Out of sort memory, consider increasing server sort buffer size in /***/***/public/wp-includes/wp-db.php on line 2056
[09-Apr-2021 07:42:38 UTC] WordPress databasefout Out of sort memory, consider increasing server sort buffer size bij query SELECT DISTINCT links.*
FROM wp_blc_links AS links
				INNER JOIN wp_blc_instances AS instances USING(link_id)
				WHERE
					(
						( last_check_attempt < '2021-03-30 07:42:38' )
						OR
						(
							(broken = 1 OR being_checked = 1)
							AND may_recheck = 1
							AND check_count < 3
							AND last_check_attempt < '2021-04-09 07:12:38'
						)
					)

				AND
					( instances.container_type IN ('comment', 'post', 'page', 'dummy') )
					AND ( instances.parser_type IN ('link', 'image', 'metadata', 'url_field', 'acf') )
				
ORDER BY last_check_attempt ASC
LIMIT 30 gemaakt door include('phar:///***/***/wp/php/boot-phar.php'), include('phar:///***/***/wp/vendor/wp-cli/wp-cli/php/wp-cli.php'), WP_CLI\bootstrap, WP_CLI\Bootstrap\LaunchRunner->process, WP_CLI\Runner->start, WP_CLI\Runner->run_command_and_exit, WP_CLI\Runner->run_command, WP_CLI\Dispatcher\Subcommand->invoke, call_user_func, WP_CLI\Dispatcher\CommandFactory::WP_CLI\Dispatcher\{closure}, call_user_func, Cron_Event_Command->run, Cron_Event_Command::run_event, do_action_ref_array('blc_cron_check_links'), WP_Hook->do_action, WP_Hook->apply_filters, wsBrokenLinkChecker->cron_check_links, wsBrokenLinkChecker->work, wsBrokenLinkChecker->get_links_to_check

Hi @wpmudevsupport12 I contacted the developers of the platform we use, this is their answer:

I haven’t seen this error or mysql variable before. Reading through some other project issues like https://github.com/mozilla/addons-server/issues/15970 , it seems this happens when one tries to order by a field which is not index. In the query above, I guess last_check_attempt is not indexed. Can you ask the dev to maybe make an index. I think otherwise, the fix is to order with the primary key or some other indexed key.

It seems your config of the query and table/index could fix it and then you’ll make more of your users/customers happy!

• This reply was modified 3 years ago by MarcelC.

@wpmudevsupport12 @wpmudev-support8

Had your hosting increased the buffer size for a test?

It’s self hosting, I added the buffer size and indeed it all works now. However the setting is not persistent (docker) and none of the many applications using this MySQL needed it before.

I guess the real solution is to optimize the query.

4 months later and still no optimized query?