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 ! >>>>>>> >>>>>>>
