fix: (CalDav) Delete invitation link when deleting Calendars or Events

[SebastianKrupinski]

• Resolves: When a calendar event is deleted, corresponding calendar_invitation entries are not deleted #12387

Summary

When deleting a calendar or event also delete event invitation links

[tcitworld]

We also need a repair step to purge all entries in calendar_invitations which don't match existing calendar objects.

[tcitworld]

Won't this explode on Oracle if there's a lot of events for the calendar?

server/lib/private/DB/QueryBuilder/QueryBuilder.php

Line 220 in a2cfcf3

$exception = new QueryException('More than 1000 expressions in a list are not allowed on Oracle.');

Ah no, it's raw SQL being passed.

Maybe a join between tables is better here?

[SebastianKrupinski]

Morning, if that is the case with Oracle then yes this will need to get reworked.

[SebastianKrupinski]

Looks like join delete will not work... due to lack of alias support in DBAL.

We would need to execute something like this...

DELETE i
FROM oc_calendar_invitations i
INNER JOIN oc_calendarobjects o ON o.uid = i.uid
WHERE o.calendarid = 3432

And DBAL does not support DELETE i FROM...
https://github.com/doctrine/dbal/blob/7a8252418689feb860ea8dfeab66d64a56a64df8/src/Connection.php#L392

So our options are...

1. Using a raw sql statement (probably the most efficient)
2. Extending our DBAL implementation to support aliases and using a join (not sure this will really fly)
3. Pulling the UID's from CalendarObjects, splitting them up in chunks of 1k or smaller, and executing a "where in" on each chunk.

Lets have @ChristophWurst weigh in on this.

[tcitworld]

The raw SQL statement sounds the best then.

[ChristophWurst]

SELECT, chunk and DELETE like nextcloud/mail#9761

[miaulalala]

We also need a repair step to purge all entries in calendar_invitations which don't match existing calendar objects.

Set the expiration date for those outdated links to in the past, and the CleanupInvitationTokenJob will take care of it.

https://github.com/nextcloud/server/blob/af6de04e9e141466dc229e444ff3f146f4a34765/apps/dav/lib/BackgroundJob/CleanupInvitationTokenJob.php

It will probably need modifications like

server/apps/dav/lib/BackgroundJob/DeleteOutdatedSchedulingObjects.php

Lines 30 to 34 in af6de04

	protected function run($argument): void {
	$time = $this->time->getTime() - (60 * 60);
	$this->calDavBackend->deleteOutdatedSchedulingObjects($time, 50000);
	$this->logger->info('Removed outdated scheduling objects');
	}

as to not completely crash an instance until all outdated links are deleted.

Would be a good idea to get some data from our instance too to see how many of these links exist in our database. Please ask the sysadmins to run a query for you.

[tcitworld]

In my production instance, with ~22k rows in oc_calendar_invitations and 22M rows in oc_calendarobjects, I get 2162 entries for

select count(i.id) from oc_calendar_invitations i left join oc_calendarobjects o on i.uid = o.uid where o.id is null;

[SebastianKrupinski]

In my production instance, with ~22k rows in oc_calendar_invitations and 22M rows in oc_calendarobjects, I get 2162 entries for

22M rows! wow. Can you tell how many calendar object the biggest calendar has?

[tcitworld]

Can you tell how many calendar object the biggest calendar has?

51k objects