Hi Georg, I stumbled upon the problem in the server source tree that ucontext check is broken, causing the non-blocking library to be completely disabled on all non-x86 platforms. After creating my own patch, I noticed that you alrady made a patch for this in MDEV-9112, but it does not appear to be pushed yet. Do you still want to push your patch? The patch looks fine (you can take this as review), it handles a couple things I forgot in my own patch. I think this should definitely go in 10.0 (and 10.1) - but do you think it should go in 5.5 also (not sure)? - Kristian. PS. I supplied a patch in CONC-153 for the similar problem in mariadb-connector-c, but maybe you are already aware of that as well. It was BTW cool to see that an application of mine (originally written against libmysqlclient) worked without changes on mariadb-connector-c.