47fa88d947
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
Change-Id: I17e0eb836dd87aac5859f506e7d771d42753d31a
11 lines
450 B
YAML
11 lines
450 B
YAML
---
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fixes:
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Fixes `bug 1691545`_ in which there was a significant increase in database
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connections because of the way connections to cell databases were being
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established. With this fix, objects related to database connections are
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cached in the API service and reused to prevent new connections being
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established for every communication with cell databases.
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.. _bug 1691545: https://bugs.launchpad.net/nova/+bug/1691545
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