Glace return HTTPInternalServerError when use postgresql

[wangxiyuan]

version: master, db: postgreSQL

reproduce:

1.create one or more images without data, like:
glance image-create --name xxx or glance image-create

then we will get image information though 'glance image-list', like:

+--------------------------------------+--------------------------+-------------+------------------+---------+--------+
| ID | Name | Disk Format | Container Format | Size | Status |
+--------------------------------------+--------------------------+-------------+------------------+---------+--------+
| 67b47035-3e70-4dd0-a5a7-3fc3350a26ee | cirros-0.3.0-x86_64-disk | qcow2 | bare | 9761280 | active |
| bf8022ef-3e3a-4bef-8d13-ccea9000828f | test | | | | queued |
| 0180e9f2-6506-46c7-be07-e67ee6d5dab8 | test2 | | | | queued |
| 505bbc97-f470-44b7-bb59-315a5d92d8e0 | test3 | | | | queued |
| 03ef4387-f276-40dc-9aa6-ad811eb3c466 | test5 | | | | queued |
| 5af5d95d-8c2f-4bec-9fdd-74ce9ce3a4ca | | | | | queued |
+--------------------------------------+--------------------------+-------------+------------------+---------+--------+

2.list image like : glance image-list --sort-key=size --page-size=3 (sort-key must be 'size', and page-size must be less than or equal to image amount )

then, glance will return an error:
HTTPInternalServerError (HTTP 500)

P.S.:When use mysql db, I didn't encounter this problem.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/208851

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/208851
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=d13f088cac92988f3360363d9d34b60b518d18e9
Submitter: Jenkins
Branch: master

commit d13f088cac92988f3360363d9d34b60b518d18e9
Author: wangxiyuan <email address hidden>
Date: Tue Aug 4 14:35:46 2015 +0800

    Fix default value with postgreSQL

    When use 'sort-key=size' for multi-pages searching with postgreSQL
    DB, it will raise an error: DBError: (psycopg2.DataError). And return
    HTTPInternalServerError (HTTP 500) to users. The reason is that
    postgreSQL doesn't support the size's default value to be string.
    This patch set the size's default value to zero.

    Change-Id: Ib3b5f3f57be3683ba274f0122e6314978a79e75f
    Closes-bug:#1481154