Rich Prohaska <[email protected]> writes: > On Tue, Aug 23, 2016 at 1:45 PM, Kristian Nielsen <[email protected]> > wrote:
>> In the original parallel replication patch, thd_report_wait_for() did not >> call back directly into tokudb_kill_query(). The kill happened >> asynchronously, in a separate background thread. Then there is no problem >> with TokuDB (or InnoDB) holding locks over the call to >> thd_report_wait_for(). >> >> I am considering re-introducing that orginal code - this might simplify >> TokuDB implementation (and would also simplify InnoDB implementation). >> I was never very happy about the way thd_report_wait_for() works currently. Ok, so I implemented this, available in this branch: https://github.com/knielsen/server/commits/toku_opr3 With this code, I am no longer able to reproduce any hangs with the tests I've been running so far. > BTW, the current_lock_tree_mutex logic is broken. The underlying tokuft > lock manager has one manager object (and its mutex) and many lock tree > objects (each with its own mutex). Since the thd_report_wait_for function > is called when holding the lock tree mutex (not the manager mutex), it can > be called in parallel; thus there is a race on the current_lock_tree_mutex > logic. Yes, and this is the main problem solved by doing the kill asynchronously. And from my tests, it looks like this was actually what was causing the problems - crash, assertion, and hangs. (I haven't determined this conclusively, but it seems at least plausible). It really was always an ugly hack around the locking problem with thd_report_wait_for() (InnoDB had a similar issue), it seems good to get rid of it. I still have the should_retry_lock_requests disabled in retry_all_lock_requests() - otherwise I get hangs. I haven't investigated this deeply yet. I also want to go back over the entire set of patches and see what needs cleaning up, and think about how this could go into 10.2 and possibly 10.1. - Kristian. _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
