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Hi Oslo Team,

Can we retain “blocking” executor for now in Oslo Messaging?


Some background..

For a while we had to use Oslo Messaging with “blocking” executor in Mistral because of incompatibility of MySQL driver with green threads when choosing “eventlet” executor. Under certain conditions we would get deadlocks between green threads. Some time ago we switched to using PyMysql driver which is eventlet friendly and did a number of tests that showed that we could safely switch to “eventlet” executor (with that driver) so we introduced a new option in Mistral where we could choose an executor in Oslo Messaging. The corresponding bug is [1].

The issue is that we recently found that not everything actually works as expected when using combination PyMysql + “eventlet” executor. We also tried “threading” executor and the system seems to work with it but surprisingly performance is much worse.

Given all of that we’d like to ask Oslo Team not to remove “blocking” executor for now completely, if that’s possible. We have a strong motivation to switch to “eventlet” for other reasons (parallelism => better performance etc.) but seems like we need some time to make it smoothly.


[1] https://bugs.launchpad.net/mistral/+bug/1696469


Thanks

Renat Akhmerov
@Nokia
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