Flavors list results not limited on database server-side

[Jay Pipes]

while investigating the source of bug 1028465, I discovered to my chagrin that Nova's list results are not limited using the database query. Instead, nova.api.openstack.common.limited_by_marker is actually looping over the entire set of non-limited results from the database. This is incredibly inefficient. We should be passing marker and limit to the database query itself, like is done in Glance.

[Alex Meade (alex-meade)]

This is very true, before this can be done the filtering for results also needs to be done in the db, as to not remove things from limited pages. This MP handles this case: https://review.openstack.org/#/c/10917/

Once this is true it is as simple as paginating and limiting just as Glance does.

[Sean Dague (sdague)]

The only place where this is still a problem is the flavor api. This would require adding limit and paging interfaces into it's db api, then exposing them in the interface. Pretty straight forward, and worth doing in H.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/24591

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/24592

[Joshua Hesketh (joshua.hesketh)]

Howdy,

This is my first attempt at a bug fix in nova and I've gotten a little bit stuck. Basically my change seems to pass most of the unit tests but is somehow preventing new instances from launching (clearly a big deal). I'm not really sure how to debug it further due to my unfamiliarity with the system. Any thoughts?

Additionally, and perhaps more a topic for the mailing list, I'm not sure how to write a test for the database methods. It seems like the unit test queries are faked so nova.db.sqlalchemy.api.instance_type_get_all() is never entered into or checked accurately. Should I be writing an additional test to somehow check this function?

Cheers,
Josh

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/24592
Committed: http://github.com/openstack/nova/commit/08b2433dddc6e38448b3648c47b44acb595b5014
Submitter: Jenkins
Branch: master

commit 08b2433dddc6e38448b3648c47b44acb595b5014
Author: Joshua Hesketh <email address hidden>
Date: Thu Aug 15 09:36:49 2013 +1000

    Offer a paginated version of flavor_get_all

    Implements nova.compute.flavors.get_all_flavors_sorted_list to
    optimise get_all_flavors.

    Fixes: bug #1028494
    Change-Id: Ie0406c1d4b47a51473979910c0908b153497d503