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

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

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: 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

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: 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