openstack
/
neutron
Code Issues Proposed changes

Make query in quota api lockless 

As one of query to fetch quota usage by resource and tenant
was done in lock mode earlier. This was done to protect the
dirty bit in the usage which tracks for update. For moving to
OVO carrying lock mode can be avoided by making sure that dirty
attribute of quotausages is still protected.

Change-Id: I0bb9f6fb7be51be590afb527a56e0569e922e98f
Partially-Implements: blueprint adopt-oslo-versioned-objects-for-db
This commit is contained in:
Manjeet Singh Bhatia 2017-03-06 21:39:30 +00:00
parent 877d08b3fe
commit 85b70a9c18
2 changed files with 5 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
neutron/db/quota/api.py
View File

@ -41,22 +41,21 @@ class ReservationInfo(collections.namedtuple(
@db_api.retry_if_session_inactive()
def get_quota_usage_by_resource_and_tenant(context, resource, tenant_id,
lock_for_update=False):
def get_quota_usage_by_resource_and_tenant(context, resource, tenant_id):
"""Return usage info for a given resource and tenant.
:param context: Request context
:param resource: Name of the resource
:param tenant_id: Tenant identifier
:param lock_for_update: if True sets a write-intent lock on the query
:returns: a QuotaUsageInfo instance
"""
query = db_utils.model_query(context, quota_models.QuotaUsage)
query = query.filter_by(resource=resource, tenant_id=tenant_id)
if lock_for_update:
query = query.with_lockmode('update')
# NOTE(manjeets) as lock mode was just for protecting dirty bits
# an update on dirty will prevent the race.
query.filter_by(dirty=True).update({'dirty': True})
result = query.first()
if not result:

2
neutron/quota/resource.py
View File

@ -250,7 +250,7 @@ class TrackedResource(BaseResource):
"""
# Load current usage data, setting a row-level lock on the DB
usage_info = quota_api.get_quota_usage_by_resource_and_tenant(
context, self.name, tenant_id, lock_for_update=True)
context, self.name, tenant_id)
# Always fetch reservations, as they are not tracked by usage counters
reservations = quota_api.get_reservations_for_resources(
context, tenant_id, [self.name])