[openstack-dev] [nova][db] Thoughts on making instances.uuid non-nullable?

David Ripton dripton at redhat.com
Mon Mar 10 14:31:35 UTC 2014

On 03/10/2014 10:11 AM, Matt Riedemann wrote:
> On 3/9/2014 9:18 PM, Jay Pipes wrote:
>> On Mon, 2014-03-10 at 10:05 +0800, ChangBo Guo wrote:
>>> 2014-03-10 4:47 GMT+08:00 Jay Pipes <jaypipes at gmail.com>:
>>>          > 3. This would make the instances and shadow_instances tables
>>>          have
>>>          > different schemas, i.e. instances.uuid would be
>>>          nullable=False in
>>>          > instances but nullable=True in shadow_instances.  Maybe this
>>>          doesn't matter.
>>>          No, I don't think this matters much, to be honest. I'm not
>>>          entirely sure
>>>          what the long-term purpose of the shadow tables are in Nova --
>>>          perhaps
>>>          someone could clue me in to whether the plan is to keep them
>>>          around?
>>> As I know the tables shadow_*  are used  by command ' nova-manage db
>>> archive_deleted_rows' , which moves  records with "deleted=True" to
>>> table shadow_* . That means these tables are used by other  process,
>>> So, I think we need other tables to store the old records in your
>>> migration.
>> Yeah, that's what I understood the shadow tables were used for, I just
>> didn't know what the long-term future of these tables was... curious if

> I think Joe Gordon was working on something in the hopes of eventually
> killing the shadow tables but I can't remember exactly what that was now.


It didn't get done for Icehouse.  Maybe it will for Juno.

Everyone agrees that db-archiving is not ideal, but we probably want 
something better in place before we rip it out.

David Ripton   Red Hat   dripton at redhat.com

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