Convention in the yaml is default being visible commented out.
On Wed, Oct 13, 2021 at 2:17 PM S G <sg.online.em...@gmail.com> wrote: > 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 ! >>>>>>>>> >>>>>>>>>
