openstack
/
neutron
Code Issues Proposed changes

Remove SELECT FOR UPDATE use in delete_firewall 

SELECT FOR UPDATE expression, which is triggered with the use of the
SQLAlchemy Query object's with_lockmode('update') method, is
detrimental to performance and scalability of the database
performance code in Neutron due to the lock contention it produces.

SELECT FOR UPDATE can be entirely avoided in delete_firewall method
with the use of single-shot DELETE expressions.

Partial-Bug: #1364358
Change-Id: Ia8db73312f5dff6a5bd573694a60a798279834cb
This commit is contained in:
Cedric Brandily 2014-08-26 20:23:04 +02:00
parent 2f79320552
commit 187217d767
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
neutron/db/firewall/firewall_db.py
View File

@ -264,12 +264,11 @@ class Firewall_db_mixin(firewall.FirewallPluginBase, base_db.CommonDbMixin):
def delete_firewall(self, context, id):
LOG.debug(_("delete_firewall() called"))
with context.session.begin(subtransactions=True):
fw_query = context.session.query(
Firewall).with_lockmode('update')
firewall_db = fw_query.filter_by(id=id).one()
# Note: Plugin should ensure that it's okay to delete if the
# firewall is active
context.session.delete(firewall_db)
count = context.session.query(Firewall).filter_by(id=id).delete()
if not count:
raise firewall.FirewallNotFound(firewall_id=id)
def get_firewall(self, context, id, fields=None):
LOG.debug(_("get_firewall() called"))