Reading data from disk

Hello Team, Here is a simple query. Whenever a select query is being run with cluster columns in where clause, does it happen that the entire partition is being read from disk to memory and then iterated over to fetch the required result set. Or there are indexes in place which help read only spe

High frequency garbage collection leading to High load average

Hello team, On a given day , a node in 27 node cluster observed higher frequency of garbage collection. Mostly young gc. I have found below issues: 1. Higher number of slow queries being observed on that particular node for that particular day compared to other days 2. Higher outgoing traffic ob

Multi dc replication failing

Hello Team, I have a multi dc Cassandra setup. We write and read using local quorum to a particular datacenter A The replica definition in schema is correct. Sometimes we don't see data getting correctly replicated to datacenter B. I need to know what may be different ways to troubleshoot this.

Continuous hints getting generated even when nodes are Up

Hello Team, I'm using Cassandra 3.0.9. Recently I have observed that, all the nodes in my cluster are generated hints. All the nodes are up but I do see hints getting generated continuously. In the logs I see tombstone warnings, but frequency is less I also see frequent message Unknown column d

Cross DC replication failing

Hello team, Greetings. Simple question Using Cassandra 3.0.8 Writing to DC-A using local_quorum Reading the same data from a DC-B using local quorum. It succeeds for a table and fails for other. Data written is not replicated immediately even after a long time. However if read is performed using

Full repair results in uneven data distribution

Hello Team, Sorry for this might be a simple question. I was working on Cassandra 2.1.14 Node1 -- 4.5 mb data Node2 -- 5.3 mb data Node3 -- 4.9 mb data Node3 was down since 90 days. I brought it up and it joined the cluster. To sync data I ran nodetool repair --full Repair was successful...how

Re: Facing issues while starting Cassandra

wing command before running? > export LC_ALL=C; > > Regards, > Osman > > On Tue, 24 Dec 2019 at 09:01, Inquistive allen > wrote: > > > > Hello Jeff, > > > > Thanks for responding. > > I have validated the cassandra.yaml file with other hosts in the clu

Re: Facing issues while starting Cassandra

19, at 12:51 PM, Inquistive allen > wrote: > >  > Hello Team, > > I am facing issues while starting Cassandra. > > Caused by: org.apache.cassandra.exceptions.ConfigurationException : > Invalid yaml: file: /path/to/yaml > Error: null ; can't co

Facing issues while starting Cassandra

Hello Team, I am facing issues while starting Cassandra. Caused by: org.apache.cassandra.exceptions.ConfigurationException : Invalid yaml: file: /path/to/yaml Error: null ; can't construct a java object for tag: yaml.org,2002:org.apache.cassandra.config.Config; exception= java.lang.reflect.Invoca

Re: Cassandra is not showing a node up hours after restart

prod-cassandra -a date > > node001.intra.myorg.org | CHANGED | rc=0 >> > > Mon Nov 25 13:58:17 UTC 2019 > > > > node004.intra.myorg.org | CHANGED | rc=0 >> > > Mon Nov 25 14:07:20 UTC 2019 > > > > node003.intra.myorg.org | CHANGED | rc=0 >

Re: Cassandra is not showing a node up hours after restart

Hello team, Just to add on to the discussion, one may run, Nodetool disablebinary followed by a nodetool disablethrift followed by nodetool drain. Nodetool drain also does the work of nodetool flush+ declaring in the cluster that I'm down and not accepting traffic. Thanks On Mon, 25 Nov, 2019,

Select statement in batch

Hello Team, Wanted to understand the impacted of using a select statement inside a batch. I keep seeing some slow queries frequently in the logs. Please comment on what may the impact of the same. Is it the right practice. Will a select statement in batch be lead to increase in read latency than

Re: Cassandra loglevel in 3.11.x version

Hello Jai, If you want to fetch queries from the logs. Kindly run the below command: nodetool setlogginglevel org.apache.cassandra.transport TRACE this will help you see all your queries in logs. Just beware that this fills up logs really fast. Thanks, Allen On Fri, 6 Sep, 2019, 10:57 AM Jai

Re: Consistent hashing vnodes and ring in cassandra

at 10:53 AM, Inquistive allen > wrote: > > > > I am a newbie in cassandra. I have asked this question on various > platforms but never got a satisfying answer. > > Hence thought of bringing up the topic here. Sorry for this might be a > simple question. > > > >

Consistent hashing vnodes and ring in cassandra

I am a newbie in cassandra. I have asked this question on various platforms but never got a satisfying answer. Hence thought of bringing up the topic here. Sorry for this might be a simple question. 1. I studied the paper on consistent hashing (which is being implemented in Cassandra) 2. Cassan