hi Peter, i was helping some guys in a datacenter here in brazil and they implement server hosting via virtual machines, in other words, they have a very big linux cluster and many virtual machines with memory/cpu restrictions, maybe that's the solution they give... in each virtual machine they run a 'small server', it's a very 'expensive' solution, but works... a cheaper one could be a per process restriction via variables tunes / os restrictions there's some others mysql patchs (github lauchpad others) that limit mysql resources, but i didn't used --- getting back to your idea: "SET PRIOTITY = xxxx FOR processlist.id=xxxx" what this should do? change 'nice' value of linux pid? it can help, but i tryed this some times and when problem is disk i/o limit it don't 'solve' the problem, just help i see a better solution using the MDEV-4623 that i told, and this others MDEVs (MDEV-4615 <https://mariadb.atlassian.net/browse/MDEV-4615> - vertical partitioning, MDEV-3932<https://mariadb.atlassian.net/browse/MDEV-3932> - mysql 5.6 merge) with vetical/horizontal partitioning and partition lock prunes with vertical/horizontal partitioning + partition lock prunes, we can "change" a myisam table with table lock level, to a myisam table with 'partition lock' level, and implement a good partitioning that help us to minimize the lock contention, and after we can change query cache to prune partitions too, giving a better query cache hit rate (MDEV-4676<https://mariadb.atlassian.net/browse/MDEV-4676> ) any other idea? maybe after this mdevs an script could 'optimize' server 'online' reading query cache queries removing some queries, reading processlist and locking/unlocking some process and any other feature my ideas was added in mariadb JIRA but i don't know if this solve your problem and when someone will start development, i don't know many things about mariadb source code, and i can't develop it (not yet =], but maybe in future i can), if you want to vote that mdev we can have a better rank position in JIRA and maybe someone give more priority to this and help us developing any other ideas? i have the same problem for many queries, but in my case i can change source code of some projects, others projects i just tell developers to rewrite queries and optimize to better performace sorry my english errors that's not my main language.