This is import of bug http://bugs.mariadb.com/show_bug.cgi?id=699
[[Kolbe Kegel 2015-01-16 18:38:15 UTC]]
I opened bug #509 some time ago, but that bug was handled specifically for the case of last_insert_id(). The crux of that bug still exists in 1.0.4 GA:
In a single connection, fetching the values of the same two system variables results in the query being routed differently depending on the order of the variables.
Is there some set of variables that should always be routed to the master for some reason? If so, that should be documented.
Regardless, the order of terms in the SELECT list should not have any effect on query routing.