----- On 16 Oct, 2015, at 3:57 PM, Jean-François Gagné [email protected] wrote:
> On 2015-10-15 08:16, Kristian Nielsen wrote: >> Monty suggested changing the behaviour also for non-parallel mode - letting >> Seconds_Behind_Master reflect only events actually committed, not just read >> from the relay log. This would introduce an incompatible behaviour for >> Seconds_Behind_Master, but could perhaps be done for 10.1, if desired. Doing >> it in stable 10.0 would be more drastic. > > I agree with Monty: we should only update on commit and in both // and > non-// cases. +1 here. works for me too. > Having yo-yo in seconds-behind-master (because of a long running > transaction) should probably be considered a bug and should be fixed > (non-// case). > > The commit event (if we can call it as such) is the only reliable (-ish) > timing synchronization point in the binlog stream, all the rest depends > on execution time and session-latency. The timestamp of those > non-commit events should not be trusted for delay computation. > > Fixing that in 10.0 has too many implications, I think fixing in 10.1 is > a good target. > > If something needs to be done in 10.0, and if it is not too hard, adding > a "improved_seconds_behind_master" global variables for this behavior > could be done. In 10.0, the default value of this variable would be 0, > in 10.1 it would be 1. If that path is chosen, I think this variable > should be deprecated in 10.1 and go away in 10.2 to reduce code complexity. seconds_behind_master=commit? I tend to think people using 10.0 haven't seen or cared enough about it to be worth fixing in 10.0. -- -- Daniel Black, Engineer @ Open Query (http://openquery.com.au) Remote expertise & maintenance for MySQL/MariaDB server environments. _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
