As I said I'm not sure about it, but it will be interesting to check memory heap state with any JMX tool, e.g. https://github.com/patric-r/jvmtop
By a way, why Cassandra 2.0.14? It's quit old and unsupported version. Even in 2.0 branch there is 2.0.17 available. Best regards, Vladimir Yudovin, Winguzone - Hosted Cloud Cassandra Launch your cluster in minutes. ---- On Thu, 10 Nov 2016 05:47:37 -0500Shalom Sagges <shal...@liveperson.com> wrote ---- 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 We Create Meaningful Connections On Thu, Nov 10, 2016 at 11:02 AM, Vladimir Yudovin <vla...@winguzone.com> wrote: 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. 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 - Hosted Cloud Cassandra Launch your cluster in minutes. ---- On Thu, 10 Nov 2016 03:36:59 -0500Shalom Sagges <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 We Create Meaningful Connections 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.
