Thanks for the quick reply Vladimir. Is it really possible that ~12,500 writes per second (per node in a 12 nodes DC) are caused by memory flushes?
Shalom Sagges DBA T: +972-74-700-4035 <http://www.linkedin.com/company/164748> <http://twitter.com/liveperson> <http://www.facebook.com/LivePersonInc> We Create Meaningful Connections <https://engage.liveperson.com/idc-mobile-first-consumer/?utm_medium=email&utm_source=mkto&utm_campaign=idcsig> On Thu, Nov 10, 2016 at 11:02 AM, Vladimir Yudovin <vla...@winguzone.com> wrote: > Hi Shalom, > > so not sure, but probably excessive memory consumption by this SELECT > causes C* to flush tables to free memory. > > Best regards, Vladimir Yudovin, > > *Winguzone <https://winguzone.com?from=list> - Hosted Cloud > CassandraLaunch your cluster in minutes.* > > > ---- On Thu, 10 Nov 2016 03:36:59 -0500*Shalom Sagges > <shal...@liveperson.com <shal...@liveperson.com>>* wrote ---- > > Hi There! > > I'm using C* 2.0.14. > I experienced a scenario where a "select count(*)" that ran every minute > on a table with practically no results limit (yes, this should definitely > be avoided), caused a huge increase in Cassandra writes to around 150 > thousand writes per second for that particular table. > > Can anyone explain this behavior? Why would a Select query significantly > increase write count in Cassandra? > > Thanks! > > > Shalom Sagges > > <http://www.linkedin.com/company/164748> > <http://twitter.com/liveperson> > <http://www.facebook.com/LivePersonInc> > We Create Meaningful Connections > > <https://engage.liveperson.com/idc-mobile-first-consumer/?utm_medium=email&utm_source=mkto&utm_campaign=idcsig> > > > > This message may contain confidential and/or privileged information. > If you are not the addressee or authorized to receive this on behalf of > the addressee you must not use, copy, disclose or take action based on this > message or any information herein. > If you have received this message in error, please advise the sender > immediately by reply email and delete this message. Thank you. > > > -- This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this on behalf of the addressee you must not use, copy, disclose or take action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply email and delete this message. Thank you.
