[openstack-dev] [sqlalchemy][db][oslo.db][mistral] Is there a recommended MySQL driver for OpenStack projects?

Doug Hellmann doug at doughellmann.com
Tue Jul 3 12:47:04 UTC 2018

Excerpts from Renat Akhmerov's message of 2018-07-03 18:33:44 +0700:
> Hi,

> We’ve tried to address the bug [1] which is essentially caused
> by the fact that we saw that MySQLDb driver wasn’t compatible with
> eventlet’s green threads. In a nutshell, when we used the “eventlet”
> RPC executor (see [2]), the system would get stuck once in a while
> when dispatching green between green threads when it tried to hit
> Mysql, but since the driver wasn’t eventlet friendly it didn’t work.
> For that reason we had to use the “blocking” RPC executor so far
> for Mistral Engine that deals with DB transactions.

If you have a scaling issue that may be solved by eventlet, that's
one thing, but please don't adopt eventlet just because a lot of
other projects have.  We've tried several times to minimize our
reliance on eventlet because new releases tend to introduce bugs.

Have you tried the 'threading' executor?


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