Open Stack

-2 to 10 minute downtimes.

+1 to doing the evolution gracefully. There is a spec for doing that
from the H summit; someone just needs to implement it.

-Rob

On 25 October 2013 09:30, Michael Still <mikal at stillhq.com> wrote:
> Hi.
>
> Because I am a grumpy old man I have just -2'ed
> https://review.openstack.org/#/c/39685/ and I wanted to explain my
> rationale. Mostly I am hoping for a consensus to form -- if I am wrong
> then I'll happy remove my vote from this patch.
>
> This patch does the reasonably sensible thing of converting two
> columns from being text to varchar, which reduces their expense to the
> database. Given the data stored is already of limited length, it
> doesn't impact our functionality at all either.
>
> However, when I run it with medium sized (30 million instances)
> databases, the change does cause a 10 minute downtime. I don't
> personally think the change is worth such a large outage, but perhaps
> everyone else disagrees.
>
> Discuss.
>
> Thanks,
> Michael
>
> PS: I could see a more complicated approach where we did these changes
> "in flight" by adding columns, using a periodic task to copy data to
> the new columns, and then dropping the old. That's a lot more
> complicated to implement though.
>
> --
> Rackspace Australia
>
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-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud