f4159d1755
Recently in the gate we have seen a trace on some work-in-progress
patches:
OperationalError: (pymysql.err.OperationalError)
(1040, u'Too many connections')
and at least one operator has reported that the number of database
connections increased significantly going from Mitaka to Newton.
It was suspected that the increase was caused by creating new oslo.db
transaction context managers on-the-fly when switching database
connections for cells. Comparing the dstat --tcp output of runs of the
gate-tempest-dsvm-neutron-full-ubuntu-xenial job with and without
caching of the database connections showed a difference of 445 active
TCP connections and 1495 active TCP connections, respectively [1].
This adds caching of the oslo.db transaction context managers and the
oslo.messaging transports to avoid creating a large number of objects
that are not being garbage-collected as expected.
Closes-Bug: #1691545
[1] https://docs.google.com/spreadsheets/d/1DIfFfX3kaA_SRoCM-aO7BN4IBEShChXLztOBFeKryt4/edit?usp=sharing
Conflicts:
nova/context.py
nova/tests/unit/test_context.py
NOTE(melwitt): Conflicts caused by the fact that the set_target_cell
function doesn't exist in Ocata and message queue connections were
not stored on the context in Ocata.
Change-Id: I17e0eb836dd87aac5859f506e7d771d42753d31a
(cherry picked from commit 47fa88d947)
Team and repository tags
OpenStack Nova
OpenStack Nova provides a cloud computing fabric controller, supporting a wide variety of compute technologies, including: libvirt (KVM, Xen, LXC and more), Hyper-V, VMware, XenServer and OpenStack Ironic.
OpenStack Nova is distributed under the terms of the Apache License, Version 2.0. The full terms and conditions of this license are detailed in the LICENSE file.
API
To learn how to use Nova's API, consult the documentation available online at:
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Operators
To learn how to deploy and configure OpenStack Nova, consult the documentation available online at:
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For information on how to contribute to Nova, please see the contents of the CONTRIBUTING.rst.
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