[openstack-dev] [nova] nova-manage db archive_deleted_rows broken
andrew.laski at rackspace.com
Tue Dec 16 20:43:07 UTC 2014
On 12/12/2014 08:54 PM, melanie witt wrote:
> Hi everybody,
> At some point, our db archiving functionality got broken because there was a change to stop ever deleting instance system metadata . For those unfamiliar, the 'nova-manage db archive_deleted_rows' is the thing that moves all soft-deleted (deleted=nonzero) rows to the shadow tables. This is a periodic cleaning that operators can do to maintain performance (as things can get sluggish when deleted=nonzero rows accumulate).
> The change was made because instance_type data still needed to be read even after instances had been deleted, because we allow admin to view deleted instances. I saw a bug  and two patches  which aimed to fix this by changing back to soft-deleting instance sysmeta when instances are deleted, and instead allow read_deleted="yes" for the things that need to read instance_type for deleted instances present in the db.
> My question is, is this approach okay? If so, I'd like to see these patches revive so we can have our db archiving working again. :) I think there's likely something I'm missing about the approach, so I'm hoping people who know more about instance sysmeta than I do, can chime in on how/if we can fix this for db archiving. Thanks.
I looked briefly into tackling this as well a while back. The tricky
piece that I hit is what system_metadata should be available when
read_deleted='yes'. Is it okay for it to be all deleted system_metadata
or should it only be the system_metadata that was deleted at the same
time as the instance? I didn't get to dig in enough to answer that.
Also there are periodic tasks that query for deleted instances so those
might need to pull system_metadata in addition to the API.
>  https://bugs.launchpad.net/nova/+bug/1185190
>  https://bugs.launchpad.net/nova/+bug/1226049
>  https://review.openstack.org/#/c/110875/
>  https://review.openstack.org/#/c/109201/
> melanie (melwitt)
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
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