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Skipping major versions during upgrade #2270

Open MorrisJobke opened 7 years ago

MorrisJobke commented 7 years ago

I had some rough ideas about what we need to do until this is ready to go. Here is a first braindump. Feel free to comment on this. I can update this first entry here to have the current consensus covered.

Stuff we need to take care about

How to do the update then

Skipping old steps: We don't need to run steps with a version number equal or lower than the (previously) installed version that is listed in the database.

When to run live repair steps: But we need to question if the repair step v15 already has finished, right? Or (what I really prefer) we simply don't rely on the live migration and simply add them as usual as background job and make this very clear, that the live repair step could happen during a future version which then needs to take care to cleanup repair steps that doesn't apply or work anymore (maybe because of a changed database structure - idea removing the repair step code should be fine - then the code shouldn't be executed at all and be removed from the background jobs just fine)

Apps with dependencies to the server: When and in which order should updates of apps happen that has a dependency to the server - filesystem or user backend apps.

Specific scenario

previous installed versions: app1 v1, ldap_app v16 and server v16

Run them

@LukasReschke @rullzer @karlitschek @schiessle @icewind1991 @nickvergessen @blizzz Comments are welcome - this is only my first quick draft and we need to specify a bit more to not run into issues here.

See oc/core#14851 and oc/activity#546

blizzz commented 7 years ago

server first and then the apps (currently apps are in no specific order) - here db migrations of a version are sorted before a repair step for that version

What if in between steps of other apps require different (in between) server state?

nickvergessen commented 7 years ago

Yeah, we need some kind of dependency chain. We had the very same problem in phpBB as well: https://github.com/phpbb/phpbb/blob/master/phpBB/phpbb/db/migration/data/v31x/v312rc1.php#L23-L29 It has one migration for each release. And that one should be listed as a dependency of the app then, so they can only "depend" on releases, not on inbetween steps. However there is no "run before", because that just makes no sense.

Preventing the "future" however is really hard. Just remember one could simply have disabled an app while running NC 12, so when you reenable it in NC 14, the inbetween steps are not available because they happened long ago.

MorrisJobke commented 7 years ago

Preventing the "future" however is really hard. Just remember one could simply have disabled an app while running NC 12, so when you reenable it in NC 14, the inbetween steps are not available because they happened long ago.

For this case we should introduce a "delete app with all settings" way. And then make it mandatory to run it if the versions are too different.

MorrisJobke commented 7 years ago

When to run live repair steps: But we need to question if the repair step v15 already has finished, right? Or (what I really prefer) we simply don't rely on the live migration and simply add them as usual as background job and make this very clear, that the live repair step could happen during a future version which then needs to take care to cleanup repair steps that doesn't apply or work anymore (maybe because of a changed database structure - idea removing the repair step code should be fine - then the code shouldn't be executed at all and be removed from the background jobs just fine)

https://github.com/nextcloud/server/issues/2566

MorrisJobke commented 7 years ago

@karlitschek sadly we need to move this to 13

karlitschek commented 7 years ago

Thats ok. Thanks

jospoortvliet commented 3 years ago

An alternative approach would be: https://github.com/nextcloud/updater/issues/321

RoboMagus commented 1 year ago

How is this still not fixed after all this time?!

Just tried to upgrade from 23.x to 25.x and wound up in an unrecoverable state (or at least far easier just to restore from backup).