[horde] Database cleanup horde_histories
philipp.faeustlin at uni-hohenheim.de
Fri May 3 12:30:10 UTC 2019
Am 02.05.19 um 15:28 schrieb Michael J Rubinsky:
> Quoting Jens Wahnes <wahnes at uni-koeln.de>:
>> Michael J Rubinsky wrote:
>>> The history data doesn't really have anything to do with the
>>> *display* of entries. If the entry in question still exists in the
>>> application's backend storage, the entry will display fine. In
>>> general, the history data is used for synchronization of things like
>>> ActiveSync clients on a mobile device, or *DAV clients. If you don't
>>> care about synchronization it is generally safe to delete this
>>> information. Even if you do care about synchronization, it would
>>> generally be safe to delete REALLY old entries - basically as long as
>>> any clients you care about have synchronized since the history event
>>> date, you should be fine.
>> Thank you for explaining.
>> I think the trouble really comes in when there are in fact entries of
>> the kind I mentioned previously (e.g. monthly meeting entered into a
>> group calendar by someone who has long left the workgroup). When the
>> history records are incomplete, and there are members joining and
>> leaving the workgroup all the time, there will be issues with syncing
>> these recurring events (e.g. to mobile devices with reminders supposed
>> to be popping up there).
> I'm curious what kind of issues with syncing you see in this situation.
> With regards to syncing, the history data is ONLY used to detect if an
> entry has changed between two sync points. The actual data for the event
> entry is stored in Kronolith, outside of the history system. As long as
> the user has enough permissions to synchronize the shared calendar,
> there should be no issue. When a new user is given permissions to a
> calendar to sync, the complete calendar is synchronized at that time,
> and the "sync point" of that state is saved in association with that
> sync client. This is greatly simplified, but basically during sync the
> history system is consulted to see if any entries have been added for
> that calendar since the last sync-point the client knows about and the
> current sync-point. Anything outside of this window of time is
> irrelevant for this user. So, basically, you can delete any history
> entries that are older than the oldest sync-point a sync client is
> associated with.
Is this correct?
There is no technical reason to keep horde_histories entries of deleted
I delete a user (testuser) by cli:
Then I can clean up horde_histories for this user with no technical impacts.
SQL: Delete from horde_histories where history_who='testuser';
Will this SQL clear all the history entries of testuser?
>>> Note that history data might have auditing value in your
>>> organization, so that is also something to keep in mind as well.
>> We're pretty much in the opposite situation. We must not keep records
>> of personal data according to GDPR statutes, at least when these
>> individuals are no longer affiliated with our organization. It's hard
>> to meet these different goals at the same time, but still we strive to
>> do our best -- any help how to improve this appreciated.
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