Re: High system CPU during high write workload

Hi Ben, Thanks for your reply, we tested the same workload on kernel version 4.6.4-1.el7.elrepo.x86_64 and found the issue to be not present there. This had resulted in really high CPU in write workloads -> area in which cassandra excels. Degrading performance by atleast 5x! I suggest this mentio

Re: Schema Changes

We used cassandra migration tool for schema versioning and schema agreement. Check it out here . Short: When executing schema altering statements use these to wait for schema propagation resultSet.getExecutionInfo().isSchemaInAgreemen

Re: Schema Changes

You can start here: https://issues.apache.org/jira/browse/CASSANDRA-10699 And here: http://stackoverflow.com/questions/20293897/cassandra-resolution-of-concurrent-schema-changes In a nutshell, schema changes works best when issued serially, when all nodes are up, and reachable. When these 3 con

Schema Changes

Would someone please explain how schema changes happen? Here are some of the ring details We have 5 nodes in 1 DC and 5 nodes in another DC across the country. Here is our problem, we have a tool which automates our schema creation. Our schema consists of 7 keyspaces with 21 tables in each keyspac

Re: Some questions to updating and tombstone

If you don't want tombstones, don't generate them ;) More seriously, tombstones are generated when: - doing a DELETE - TTL expiration - set a column to NULL However tombstones are an issue only if for the same value, you have many tombstones (i.e you keep overwriting the same values with datas an

RE: Some questions to updating and tombstone

Thanks a lot for your help. We are using STCS strategy and not using TTL Is there any API that we can use to query the current number of tombstones in a CF? From: Anuj Wadehra [mailto:anujw_2...@yahoo.co.in] Sent: 2016年11月14日 22:20 To: user@cassandra.apache.org Subject: Re: Some questions to