openstack/glance
Code Issues Proposed changes

Reduce DB calls when getting an image

Browse Source 
Right now if you want to get a single image, two queries need to be
executed:
- Get image + associated locations and properties
- Get associated tags for image

Proposed solution combines these two queries into single one which gets
image and all related data - locations, properties and tags. Similar
pattern has been already implemented when querying for list of images.

Change-Id: Ic4424bb1eb1769d8f621ebe111d95961ecf08479
Closes-Bug: 1434578
This commit is contained in:
Kamil Rykowski 2015-04-08 16:29:50 +02:00
parent 0d7b292b82
commit 4734d83513
5 changed files with 52 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
glance/db/__init__.py
View File

@ -66,13 +66,14 @@ class ImageRepo(object):
def get(self, image_id):
try:
db_api_image = dict(self.db_api.image_get(self.context, image_id))
db_api_image = dict(self.db_api.image_get(self.context,
image_id,
return_tag=True))
assert not db_api_image['deleted']
except (exception.NotFound, exception.Forbidden, AssertionError):
msg = _("No image found with ID %s") % image_id
raise exception.NotFound(msg)
tags = self.db_api.image_tag_get_all(self.context, image_id)
image = self._format_image_from_db(db_api_image, tags)
image = self._format_image_from_db(db_api_image, db_api_image['tags'])
return ImageProxy(image, self.context, self.db_api)
def list(self, marker=None, limit=None, sort_key=None,

5
glance/db/registry/api.py
View File

@ -83,9 +83,10 @@ def image_destroy(client, image_id):
@_get_client
def image_get(client, image_id, force_show_deleted=False):
def image_get(client, image_id, force_show_deleted=False, return_tag=False):
return client.image_get(image_id=image_id,
force_show_deleted=force_show_deleted)
force_show_deleted=force_show_deleted,
return_tag=return_tag)
def is_image_visible(context, image, status=None):

13
glance/db/simple/api.py
View File

@ -380,7 +380,8 @@ def _sort_images(images, sort_key, sort_dir):
return images
def _image_get(context, image_id, force_show_deleted=False, status=None):
def _image_get(context, image_id, force_show_deleted=False, status=None,
return_tag=False):
try:
image = DATA['images'][image_id]
except KeyError:
@ -396,12 +397,18 @@ def _image_get(context, image_id, force_show_deleted=False, status=None):
LOG.warn(_LW('Unable to get unowned image'))
raise exception.Forbidden("Image not visible to you")
if return_tag:
image['tags'] = image_tag_get_all(context, image_id)
return image
@log_call
def image_get(context, image_id, session=None, force_show_deleted=False):
image = _image_get(context, image_id, force_show_deleted)
def image_get(context, image_id, session=None, force_show_deleted=False,
return_tag=False):
image = _image_get(context, image_id, force_show_deleted,
return_tag=return_tag)
return _normalize_locations(context, copy.deepcopy(image),
force_show_deleted=force_show_deleted)

16
glance/db/sqlalchemy/api.py
View File

@ -196,11 +196,17 @@ def _normalize_tags(image):
return image
def image_get(context, image_id, session=None, force_show_deleted=False):
def image_get(context, image_id, session=None, force_show_deleted=False,
return_tag=False):
image = _image_get(context, image_id, session=session,
force_show_deleted=force_show_deleted)
force_show_deleted=force_show_deleted,
return_tag=return_tag)
image = _normalize_locations(context, image.to_dict(),
force_show_deleted=force_show_deleted)
if return_tag:
image = _normalize_tags(image)
return image
@ -218,7 +224,8 @@ def _check_image_id(image_id):
raise exception.NotFound()
def _image_get(context, image_id, session=None, force_show_deleted=False):
def _image_get(context, image_id, session=None, force_show_deleted=False,
return_tag=False):
"""Get an image or raise if it does not exist."""
_check_image_id(image_id)
session = session or get_session()
@ -233,6 +240,9 @@ def _image_get(context, image_id, session=None, force_show_deleted=False):
if not force_show_deleted and not context.can_see_deleted:
query = query.filter_by(deleted=False)
if return_tag:
query = query.options(sa_orm.joinedload(models.Image.tags))
image = query.one()
except sa_orm.exc.NoResultFound:

22
glance/tests/functional/db/base.py
View File

@ -382,6 +382,28 @@ class DriverTests(object):
force_show_deleted=True)
self.assertEqual(self.fixtures[0]['id'], image['id'])
def test_image_get_with_tag_returning(self):
expected_tags = {UUID1: ['foo'], UUID2: ['bar'], UUID3: ['baz']}
self.db_api.image_tag_create(self.context, UUID1,
expected_tags[UUID1][0])
self.db_api.image_tag_create(self.context, UUID2,
expected_tags[UUID2][0])
self.db_api.image_tag_create(self.context, UUID3,
expected_tags[UUID3][0])
image = self.db_api.image_get(self.context, UUID1, return_tag=True)
self.assertEqual(self.fixtures[0]['id'], image['id'])
self.assertEqual(expected_tags[image['id']], image['tags'])
self.db_api.image_tag_delete(self.context, UUID1,
expected_tags[UUID1][0])
expected_tags[UUID1] = []
image = self.db_api.image_get(self.context, UUID1, return_tag=True)
self.assertEqual(self.fixtures[0]['id'], image['id'])
self.assertEqual(expected_tags[image['id']], image['tags'])
def test_image_get_not_owned(self):
TENANT1 = str(uuid.uuid4())
TENANT2 = str(uuid.uuid4())