It's not about columns, it's about rows, see example statement. In QueryProcessor#processStatement it reads rows into list, then does list.size()
2012/10/1 aaron morton <aa...@thelastpickle.com> > CQL will read everything into List to make latter a count. > > > From 1.0 onwards count paginated reading the columns. What version are you > on ? > > https://issues.apache.org/jira/browse/CASSANDRA-2894 > > Cheers > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 26/09/2012, at 8:26 PM, Віталій Тимчишин <tiv...@gmail.com> wrote: > > Actually an easy way to put cassandra down is > select count(*) from A limit 10000000 > CQL will read everything into List to make latter a count. > > 2012/9/26 aaron morton <aa...@thelastpickle.com> > >> Can you provide some information on the queries and the size of the data >> they traversed ? >> >> The default maximum size for a single thrift message is 16MB, was it >> larger than that ? >> https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L375 >> >> Cheers >> >> >> On 25/09/2012, at 8:33 AM, Bryce Godfrey <bryce.godf...@azaleos.com> >> wrote: >> >> Is there anything I can do on the configuration side to prevent nodes >> from going OOM due to queries that will read large amounts of data and >> exceed the heap available? **** >> ** ** >> For the past few days of we had some nodes consistently freezing/crashing >> with OOM. We got a heap dump into MAT and figured out the nodes were dying >> due to some queries for a few extremely large data sets. Tracked it back >> to an app that just didn't prevent users from doing these large queries, >> but it seems like Cassandra could be smart enough to guard against this >> type of thing?**** >> ** ** >> Basically some kind of setting like "if the data to satisfy query > >> available heap then throw an error to the caller and about query". I would >> much rather return errors to clients then crash a node, as the error is >> easier to track down that way and resolve.**** >> ** ** >> Thanks.**** >> >> >> > > > -- > Best regards, > Vitalii Tymchyshyn > > > -- Best regards, Vitalii Tymchyshyn
