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#openstack-nova - 2020-02-06
16:16:20 dansmith right, and those NULLs should be presumed =False by the python side
16:16:26 dansmith well,
16:16:43 dansmith maybe to get you out of the jam, but... that's not what *should* be happening
16:17:04 mnaser right yeah, you're right, hidden being null should default to false
16:17:09 mnaser let me get out of my jam and i will look at the code
16:17:43 dansmith oooh,
16:17:46 dansmith this might be a bug
16:17:48 dansmith a really bad one
16:18:01 dansmith let it be known that mriedem may have made a mistake
16:18:23 mnaser he left us with a fun one :(
16:18:39 dansmith it's not a hard fix
16:19:23 dansmith mnaser: is this the first s->t upgrade for you?
16:19:31 mnaser dansmith: no, and i didnt hit the first time
16:19:35 mnaser but i also dont think i hit that db migration issue that time too
16:19:43 dansmith oh, hrm
16:19:56 dansmith the db migration doesn't seem to have left the schema incorrect though
16:21:15 mriedem fake news
16:21:19 mnaser lol
16:21:31 mnaser dansmith: i think it acutally tried to do an update and set things hidden=0
16:21:35 dansmith mnaser: can you compare that bit of schema to one of your other clusters, and also look at the hidden values on those instances/
16:21:39 mnaser (this is a much bigger cloud)
16:21:46 mnaser and my stupid update instances set hidden=0 gave me this
16:21:50 mnaser ERROR 1180 (HY000): Got error 90 "Message too long" during COMMIT
16:21:58 dansmith mnaser: okay it shouldn't be doing that
16:21:59 mnaser so its almost like once it does the schema update, it bumps the version, and then tries to backfill default values
16:22:08 mnaser let me check the value of hidden in the other train deployemnt
16:22:11 dansmith yeah, that's not the intent of that migration for sure
16:22:13 openstackgerrit Merged openstack/nova-specs master: FUP: Fixed the invalid index in References https://review.opendev.org/705933
16:23:03 dansmith maybe in some situations sqla-migrate actually tries to patch up data for you on existing tables, which is a real problem
16:23:18 mnaser ok yeah
16:23:26 mnaser the other deployment has hidden=0 for every single record
16:23:30 dansmith and if so, this is a good example of why we don't do data transformation (intentionally) in schema migrations
16:23:31 dansmith okay damn
16:23:57 dansmith so we need to change that migration retroactively, and patch the load code to properly interpret the null as the default (which sqla does not do with default=)
16:24:10 mnaser so i think what happened is: schema updated and column added, db version bumped, backfill values to 0
16:24:22 mnaser and then i failed in the backfill, so the next run it just started from the next migration
16:24:25 dansmith yeah, and on your big cloud, that timed out
16:24:39 dansmith yeah, probably because the backfill wasn't technically a schema fail
16:24:41 dansmith which is also scary
16:25:18 mnaser i think your theory is best
16:25:23 mnaser s/theory/solution/
16:25:23 openstackgerrit Stephen Finucane proposed openstack/nova master: objects: Add MigrationTypeField https://review.opendev.org/706013
16:25:24 dansmith mnaser: can you file a bug for me to write this up against?
16:25:39 mnaser sure
16:25:47 dansmith thanks
16:26:57 mriedem fwiw i count 5 non-api db schema migrations that add a new boolean column with default=False,
16:27:05 dansmith mriedem: yup
16:27:12 mriedem if it's actually backfilling, then maybe just not an issue for those b/c they are smaller tables
16:27:13 dansmith mriedem: we've been doing this without realizing
16:27:17 dansmith yu[
16:27:22 dansmith will need a poison test too
16:27:29 dansmith like the others I have for alter operations
16:29:23 mriedem i sort of remember this discussion with jaypipes on https://review.opendev.org/#/c/557958/
16:29:26 mriedem which uses server_default
16:30:09 dansmith I guess server_default would be one option, but it involves another schema change which I think is less good since we have to backport this
16:34:30 mriedem https://docs.sqlalchemy.org/en/13/core/metadata.html#sqlalchemy.schema.Column.params.default
16:34:41 mriedem "which will be invoked upon insert if this column is otherwise not specified in the VALUES clause of the insert"
16:34:45 mriedem didn't realize it would backfill though
16:35:03 dansmith right, I always assume it fills on read too, but just insert
16:35:07 mriedem https://docs.sqlalchemy.org/en/13/core/metadata.html#sqlalchemy.schema.Column.params.server_default - "A FetchedValue instance, str, Unicode or text() construct representing the DDL DEFAULT value for the column."
16:35:23 mriedem so yeah, i guess never use default in migrations
16:35:31 dansmith right
16:35:39 mriedem but is default in the models OK?
16:35:40 mriedem i thought it was
16:36:00 dansmith it is,m
16:36:10 mriedem mnaser: just purge your db :)
16:36:13 dansmith and I just tested that the model sync test does not fail you for having default on the column and not the migration
16:36:31 mnaser mriedem: you're not wrong
16:36:36 mnaser dansmith: https://bugs.launchpad.net/nova/+bug/1862205
16:36:36 openstack Launchpad bug 1862205 in OpenStack Compute (nova) "Instances not visible when hidden=NULL" [Undecided,New]
16:37:08 dansmith mnaser: thanks
16:37:30 mnaser dansmith: if we come up/discuss a solution, i'm happy to work out a fix, i have bigger clouds to upgrade ahead of this sooo
16:38:01 dansmith mnaser: I've got a patch started, but yeah, will appreciate real testing for sure
16:39:34 mnaser dansmith: ok cool, i can try and help reviewing to my ability and id be able to provide some feedback on a cloud with 1.5 times the # of records (but only in 2 weeks :X)
16:39:48 mriedem i've still got core if you need to poke someone later
16:39:50 dansmith cool
16:41:55 melwitt I can help with review too if needed
16:52:40 gibi dansmith, efried, Sundar: I agree with the discussed direction in https://review.opendev.org/#/c/631243/55 See details in my review
16:54:33 gibi efried: is there other patches in the series that need my eyes? I can spend some extra time on the series tomorrow if needed
17:12:20 openstackgerrit Merged openstack/nova master: Don't error out on floating IPs without associated ports https://review.opendev.org/706213
17:12:26 openstackgerrit Merged openstack/nova master: nova-net: Update API reference guide https://review.opendev.org/703796
17:12:34 openstackgerrit Merged openstack/nova stable/queens: Add functional recreate test for bug 1852610 https://review.opendev.org/699705
17:12:34 openstack bug 1852610 in OpenStack Compute (nova) queens "API allows source compute service/node deletion while instances are pending a resize confirm/revert" [Low,In progress] https://launchpad.net/bugs/1852610 - Assigned to Matt Riedemann (mriedem)
17:16:11 openstackgerrit Lee Yarwood proposed openstack/nova master: libvirt: Remove native LUKS compat code https://review.opendev.org/669121
17:25:38 efried gibi: Well, I've been hoping that I would get the chance to review the series from top to bottom and be the second +2 (with dansmith) but I'm no longer sure I'm going to be able to get to it soon. So if you have time, your help would be much appreciated. But I would say you shouldn't push other stuff out of the way for it.
17:30:47 openstackgerrit Dan Smith proposed openstack/nova master: Fix instance.hidden migration and querying https://review.opendev.org/706331
17:31:16 dansmith mnaser: mriedem melwitt ^ haven't run all tests yet, so it might break other things, but that's what I'm thinking as a backportable change
17:31:34 melwitt in da club
17:34:04 dansmith gross.
17:34:55 melwitt lol wtf. never heard that before
17:35:40 sean-k-mooney in the club to mean pregnant ya ist an old old way of saying that in polite company when gossiping
17:36:23 melwitt interesting. here it means like at the dance club, in a bunch of rap songs
17:36:31 dansmith as someone who feels like society favors those who procreate unfairly, I definitely see it as "a club" in the negative sense
17:38:20 sean-k-mooney yes as i said it was used when gossiping about someone behind there back so it had a negitive over tone in many cases
17:38:52 dansmith that's not really what I meant :)
17:38:59 melwitt lol
17:39:00 mriedem i'm in da costco club
17:39:09 dansmith mnaser: how many instances in the database that failed, and how many in the one that didn't?
17:39:13 mriedem if you need a years supply of toilet paper i'm your guy
17:39:23 sean-k-mooney lol

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