ok, the link given has the value commented, so I was a bit confused. But then https://github.com/apache/cassandra/search?q=cross_node_timeout shows that default value is indeed true. Thanks for the help,
On Wed, Oct 13, 2021 at 11:26 AM Jeff Jirsa <jji...@gmail.com> wrote: > The default is true: > > https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L1000 > > There is no equivalent to `alter system kill session`, because it is > assumed that any query has a short, finite life in the order of seconds. > > > > On Wed, Oct 13, 2021 at 11:10 AM S G <sg.online.em...@gmail.com> wrote: > >> Hello, >> >> Does anyone know about the default being turned off for this setting? >> It seems like a good one to be turned on - why have replicas process >> something for which coordinator has already sent the timeout to client? >> >> Thanks >> >> On Tue, Oct 12, 2021 at 11:06 AM S G <sg.online.em...@gmail.com> wrote: >> >>> Thanks Bowen. >>> Any idea why is cross_node_timeout commented out by default? That seems >>> like a good option to enable even as per the documentation: >>> # If disabled, replicas will assume that requests >>> # were forwarded to them instantly by the coordinator, which means that >>> # under overload conditions we will waste that much extra time processing >>> # already-timed-out requests. >>> >>> Also, taking an example from Oracle kind of RDBMS systems, is there a >>> command like the following that can be fired from an external script to >>> kill a long running query on each node: >>> >>> alter system kill session >>> >>> >>> >>> >>> On Tue, Oct 12, 2021 at 10:49 AM Bowen Song <bo...@bso.ng> wrote: >>> >>>> That will depend on whether you have cross_node_timeout enabled. >>>> However, I have to point out that set timeout to 15ms is perhaps not a good >>>> idea, the JVM GC can easily cause a lots of timeouts. >>>> On 12/10/2021 18:20, S G wrote: >>>> >>>> ok, when a coordinator node sends timeout to the client, does it mean >>>> all the replica nodes have stopped processing that specific query too? >>>> Or is it just the coordinator node that has stopped waiting for the >>>> replicas to return response? >>>> >>>> On Tue, Oct 12, 2021 at 10:12 AM Jeff Jirsa <jji...@gmail.com> wrote: >>>> >>>>> It sends an exception to the client, it doesnt sever the connection. >>>>> >>>>> >>>>> On Tue, Oct 12, 2021 at 10:06 AM S G <sg.online.em...@gmail.com> >>>>> wrote: >>>>> >>>>>> Do the timeout values only kill the connection with the client or >>>>>> send error to the client? >>>>>> Or do they also kill the corresponding query execution happening on >>>>>> the Cassandra servers (co-ordinator, replicas etc) ? >>>>>> >>>>>> On Tue, Oct 12, 2021 at 10:00 AM Jeff Jirsa <jji...@gmail.com> wrote: >>>>>> >>>>>>> The read and write timeout values do this today. >>>>>>> >>>>>>> >>>>>>> https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L920-L943 >>>>>>> >>>>>>> >>>>>>> On Tue, Oct 12, 2021 at 9:53 AM S G <sg.online.em...@gmail.com> >>>>>>> wrote: >>>>>>> >>>>>>>> Hello, >>>>>>>> >>>>>>>> Is there a way to stop long running queries in Cassandra (versions >>>>>>>> 3.11.x or 4.x) ? >>>>>>>> The use-case is to have some kind of a circuit breaker based on >>>>>>>> query-time that has exceeded the client's SLAs. >>>>>>>> Example: If server response is useless to the client after 10 ms, >>>>>>>> then we could >>>>>>>> have a *query_killing_timeout* set to 15 ms (where additional 5ms >>>>>>>> allows for some buffer). >>>>>>>> And when that much time has elapsed, Cassandra will kill the query >>>>>>>> execution automatically. >>>>>>>> >>>>>>>> If this is not possible in Cassandra currently, any chance we can >>>>>>>> do it outside of Cassandra, like >>>>>>>> a shell script that monitors such long running queries (through >>>>>>>> users table etc) and kills the >>>>>>>> OS-thread responsible for that query (Looks unsafe though as that >>>>>>>> might leave the DB in an inconsistent state) ? >>>>>>>> >>>>>>>> We are trying this as a proactive measure to safeguard our clusters >>>>>>>> from any rogue queries fired accidentally or maliciously. >>>>>>>> >>>>>>>> Thanks ! >>>>>>>> >>>>>>>>
