Re: C* data modeling for time series

On 2017-07-26 05:15 (-0700), Junaid Nasir wrote: > I have a C* cluster (3 nodes) with some 60gb data (replication factor 2). > when I started using C* coming from SQL background didn't give much thought > about modeling the data correctly. so what I did was > > CREATE TABLE

Re: Data Loss irreparabley so

On 2017-07-25 15:49 (-0700), Roger Warner wrote: > This is a quick informational question. I know that Cassandra can detect > failures of nodes and repair them given replication and multiple DC. > > My question is can Cassandra tell if data was lost after a failure

Re: Uncaught exception on thread CounterMutationStage

On 2017-07-25 12:49 (-0700), David Salz wrote: > Hi, > > has anyone seen the following exception before? > > Context: > > * Cassandra 3.9, > > * single node (20 Cores / 256 GB RAM) > A single node with 20 cores and 256GB of RAM is probably not going to be

回复： 回复： tolerate how many nodes down in the cluster

as per Brooke suggests,RACs a multipile of RF. https://www.youtube.com/watch?v=QrP7G1eeQTI if we have 6 machines with RF=3,then we can set up 6 RACs or setup 3RACs,which will be better? Could you please further advise? Many thanks -- 原始邮件 -- 发件人:

C* data modeling for time series

I have a C* cluster (3 nodes) with some 60gb data (replication factor 2). when I started using C* coming from SQL background didn't give much thought about modeling the data correctly. so what I did was CREATE TABLE data ( deviceId int, time timestamp,

Re: C* data modeling for time series

all devices. After selecting the data I group them and perform other actions i.e sum, avg on fields and then display those to compare how devices are doing compared to each other. On Wed, Jul 26, 2017 at 5:32 PM, CPC wrote: > Hi Junaid, > > Given a time range do you want to

WG: How to sort result-set? / How to proper model a table?

Hey everyone, I'm new to Cassandra, going my first steps, having a problem/question regarding sorting results and proper data modelling. First of all, I read the article "We Shall Have Order!" by Aaron Ploetz (1) to get a first view on how Cassandra works. I reproduced the example in the

回复： 回复： tolerate how many nodes down in the cluster

One more question.why the # of racks should be equal to RF? For example,we have 4 machines,each virtualized to 8 vms ,can we set 4 RACs with RF3?I mean one machine one RAC. Thanks -- 原始邮件 -- 发件人: "我自己的邮箱";<2535...@qq.com>; 发送时间: 2017年7月26日(星期三) 上午10:32 收件人:

Re: C* data modeling for time series

Hi Junaid, Given a time range do you want to take all devices or a specific device? On Jul 26, 2017 3:15 PM, "Junaid Nasir" wrote: I have a C* cluster (3 nodes) with some 60gb data (replication factor 2). when I started using C* coming from SQL background didn't give much

Re: Cassandra Startup taking very long.

Thanks for the update. On Tue, Jul 25, 2017 at 10:13 PM Paulo Motta wrote: > This is address on 3.11.1 on CASSANDRA-13641. Workaround for now is > probably truncating system.prepared_statements before restart of node > as being done for now. > > 2017-07-25 11:12

Re: Timeout while setting keyspace

https://datastax-oss.atlassian.net/browse/JAVA-1002 This one says it's the driver issue,we will have a try. -- Original -- From: "";<2535...@qq.com>; Date: Wed, Jul 26, 2017 04:12 PM To: "user"; Subject: Timeout

Timeout while setting keyspace

Dear All, We are expericencing a strange issue.Currently we have a Cluster with Cassandra 2.1.13. when the applications start,it will print the following warings.And it takes long time for applications to start. Could you please advise ? 2017-07-26 15:49:20.676 WARN 11706 --- [-]

Re: read/write request counts and write size of each write

Thank you very much Kurt. I am not a java guy, need one small help. I initiated JMX connection but I am getting some exception: java -jar ~/jmxterm-1.0-alpha-4-uber.jar --url localhost:7199 Welcome to JMX terminal. Type "help" for available commands. $>run -b

Re: read/write request counts and write size of each write

You need to also have the mx4j jar in your Cassandra lib directory. Double checking you did that – its not included with the distro.You have to download it. http://mx4j.sourceforge.net/ R From: Nitan Kainth Reply-To: "user@cassandra.apache.org"

Re: 回复： tolerate how many nodes down in the cluster

Hi Brooke, Very nice presentation:https://www.youtube.com/watch?v=QrP7G1eeQTI !! Good to know that you are able to leverage Racks for gainingoperational efficiencies. I think vnodes have made life easier. I still see some concerns with Racks: 1. Usually scaling needs are driven by business

Re: C* data modeling for time series

If all of your queries like this(i mean get all devices given a a time range) Hadoop would be more appropriate since those are analytical queries. Anyway, to query such data with spark Cassandra connector your partition key could include day and hash of your deviceid as pseudo partition key

Re: read/write request counts and write size of each write

Hey Roger, I downloaded and saved the file in /var/lib/cassandra, but getting same error: java -jar /tmp/jmxterm-1.0-alpha-4-uber.jar --url localhost:7199 Welcome to JMX terminal. Type "help" for available commands. $>run -b org.apache.cassandra.metrics:type=ClientRequest scope=CASWrite

Re: read/write request counts and write size of each write

I think that is not the correct lib directory.You want it under $CASSANDRA_HOME/lib. Ie wherever you deployed cassandra distro into / lib That directory should be loaded with *.jar files. That is the directory you want. Roger From: Nitan Kainth Reply-To:

?????? ?????? tolerate how many nodes down in the cluster

Kurt/All, why the # of racks should be equal to RF? For example,we have 2 DCs each 6 machines with RF=3,each machine virtualized to 8 vms , can we set 6 racs with RF3? I mean one machine one RAC to avoid hardware errors or only set 3 racs,1 rac with 2 machines,which is better? Thanks

Re: read/write request counts and write size of each write

Nitan, I'm not really familiar with jmxterm but the error it's returning to you is because that MBean doesn't exist. The full MBean matching your example is org.apache.cassandra.metrics:type=ClientRequest,scope=CASWrite,name=MutationSizeHistogram. You can then call the operation values on it to