2015-06-19 12:08 GMT+02:00 Ben RUBSON <ben.rub...@gmail.com>: > > 2015-06-18 22:52 GMT+02:00 shawn l.green <shawn.l.gr...@oracle.com>: >> >> On 6/18/2015 2:10 PM, Ben RUBSON wrote: >>> >>> Hello, >>> >>> In order for the slave to quickly show a communication issue between >>> the master and the slave, I set slave_net_timeout to 10. >>> "show slave status" then quickly updates, perfect. >>> >>> I would also like the master to quickly show when the slave is no more >>> reachable. >>> >>> However, "show processlist" and "show slave hosts" take a very long >>> time to update their status when the slave has gone. >>> Is there any way to have a refresh rate of about 10 seconds, as I did >>> on slave side ? >> >> There are two situations to consider >> >> 1) The slave is busy re-trying. It will do this a number of times then >> eventually disconnect itself. If it does disconnect itself, the processlist >> report will show it as soon as that happens. > > Yes, I confirm. > >> 2) The connection between the master and slave died (or the slave itself is >> lost). In this case, the server did not receive any "I am going to >> disconnect" message from its client (the slave). So as far as the server is >> concerned, it is simply sitting in a wait expecting the client to eventually >> send in a new command packet. >> >> That wait is controlled by --wait-timeout. Once an idle client connection >> hits that limit, the server is programmed to think "the idiot on the other >> end of this call has hung up on me" so it simply closes its end of the >> socket. There are actually two different timers that could be used, >> --wait-timeout or --interactive-timeout and which one is used to monitor the >> idle socket depends entirely on if the client did or did not set the >> 'interactive flag' when it formed the connection. MySQL slaves do not use >> that flag. >> >> Now, if the line between the two systems died in the middle of a >> conversation (an actual data transfer) then a shorter -net-write-timeout or >> --net-read-timeout would expire and the session would die then. > > This is the interesting part yes, when the connection dies (whatever > the link status is at this moment, idle or not). > So I set wait_timeout=10. > > When the link is up, we clearly see that the idle connection is reset > every 10 seconds : the "show processlist" clearly shows that the slave > TCP source port changes, and time is reset from 10 to 0. > Perfect.
Well this behavior is due to slave_net_timeout, not to wait_timeout. So neither wait_timeout nor interactive_timeout (expected), net_read_timeout, net_write_timeout helped. > However, when the link dies, the "Binlog Dump" process stays in the > "show processlist", I have to wait more than 1000 seconds for it to > disappear. > I made tests adding interactive_timeout=10, net_read_timeout=10 and > net_write_timeout=10, however the behavior is the same. > > Did I miss something ? > > Of course goal is to monitor replication, from the slave (done and > working thanks to slave_net_timeout), but from the master too (some > more tuning needed), as we never know which one will be able to > transmit the alert properly. > > Thank you very much Shawn. Thank you again, Best regards, Ben -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
