[openstack-dev] [oslo.db] PyMySQL review

Roman Podoliaka rpodolyaka at mirantis.com
Thu Jan 29 16:35:20 UTC 2015

Hi all,

Mike, thanks for summarizing this in
https://wiki.openstack.org/wiki/PyMySQL_evaluation !

On PyMySQL: this is something we need to enable testing of oslo.db on
Python 3.x and PyPy. Though, I doubt we want to make PyMySQL the
default DB API driver for OpenStack services for Python 2.x. At least,
not until PyMySQL provides C-speedups for hot spots in the driver code
(I assume this can be done in eventlet/PyPy friendly way using cffi).
Otherwise, PyMySQL would be much slower than MySQL-Python for the
typical SQL queries we do (e.g. ask for *a lot* of data from the DB).

On native threads vs green threads: I very much like the Keystone
approach, which allows to run the service using either eventlet or
Apache. It would be great, if we could do that for other services as


On Thu, Jan 29, 2015 at 5:54 PM, Ed Leafe <ed at leafe.com> wrote:
> Hash: SHA1
> On 01/28/2015 06:57 PM, Johannes Erdfelt wrote:
>> Not sure if it helps more than this explanation, but there was a
>> blueprint and accompanying wiki page that explains the move from twisted
>> to eventlet:
> Yeah, it was never threads vs. greenthreads. There was a lot of pushback
> to relying on Twisted, which many people found confusing to use, and
> more importantly, to follow when reading code. Whatever the performance
> difference may be, eventlet code is a lot easier to follow, as it more
> closely resembles single-threaded linear execution.
> - --
> - -- Ed Leafe
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