Re: Query regarding spark on cassandra

Hi, could it be consistency level issue? If you use ONE for reads and writes, might be that sometimes you don't get what you are writing. See: https://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_config_consistency_c.html Br, Hannu 2016-04-27 20:41 GMT+03:00 Siddharth Verma

Scenarios when a node can be missing writes

isk if "commitlog_sync" is "periodic" (which it is by default) and "commitlog_sync_period_in_ms" is 10 seconds. Can this be a cause of node missing writes if the server has stayed on for the whole time and only cassandra has restarted? Any other scenarios? Cheers, Hannu Kröger

Re: Data modelling, including cleanup

Hi, That’s how I have done it in many occasions. Nowadays there is the possibility use Cassandra 3.0 and materialised views so that you don’t need to keep two tables up to date manually: http://www.datastax.com/dev/blog/new-in-cassandra-3-0-materialized-views

Re: DATA replication from Oracle DB to Cassandra

Hi, I have implemented once one way replication from a RDBMS to Cassandra using triggers in the source database side. If you timestamp the changes from the source, it’s possible to timestamp them on the cassandra side as well and that takes care of a lot of ordering of the changes. Assuming

Re: Nodes go down periodically

Hi, Those are probably GC pauses. Memory tuning is probably needed. Check the parameters that you already have customised if they make sense. http://blog.mikiobraun.de/2010/08/cassandra-gc-tuning.html Hannu > On 23 Feb 2016, at

Re: opscenter doesn't work with cassandra 3.0

Is it really like that? Where does this info come from? I haven’t seen anything “official" yet. Hannu > On 26 Jan 2016, at 15:07, > wrote: > > This is a very strange move considering how well DataStax has supported open > source

Re: [RELEASE] Apache Cassandra 3.1 released

Hi, I feel the same as well. Would you skip 3.2 when you release another round of bug fixes after one round of bug fixes? Or would 3.2 be released after 3.3.? :P BR, Hannu > On 09 Dec 2015, at 16:05, Kai Wang wrote: > > Janne, > > You are not alone. I am also confused by

Re: Any problem mounting a keyspace directory in ram memory?

At least I cannot think of any reason why it wouldn't work. As you said, you might lose the data but if you can live with that then why not. Hannu On 02.02.2015, at 14:21 , Gabriel Menegatti gabr...@s1mbi0se.com.br wrote: Hi Colin, Yes, we don't want to use the C* in-memory, we just want

Re: Is it possible to flush memtable in one virtual center?

Hi, You have memtables on each machine. So 1) Yes 2) Yes, in any case you have to run nodetool flush for each node that you want to flush. In this case you run flush each node in your analytics DC. Hannu 2014-12-16 1:20 GMT+02:00 Benyi Wang bewang.t...@gmail.com: We have one ring and two

Re: how wide can wide rows get?

The theoretical limit is maybe 2 billion but recommended max is around 10-20 thousand. Br, Hannu On 14.11.2014, at 8.10, Adaryl Bob Wakefield, MBA adaryl.wakefi...@hotmail.com wrote: I’m struggling with this wide row business. Is there an upward limit on the number of columns you can

Re: Commissioning failure

Hi, I think only LevelledCompactionStrategy makes sense on JBOD because that can distribute data more evenly. Although I don't know what is the exact strategy where each compaction strategy will store sstables. If you use SizeTieredCompactionStrategy you might run into problems when sstables get

Re: Commissioning failure

You can change it on the fly. That will just compact all the data that you have so it will take a long time and cause some io load. Hannu On 31.10.2014, at 14.07, venkat sam samvenkat...@outlook.com wrote: Yes Hannu, Initially for one month we didn't face any problem. But once tables

Re: Anyone know when DSE will support Cassandra 2.1?

Based on history, there is typically a 6 month delay between Cassandra release and related DSE release. Hannu 2014-10-14 22:20 GMT+03:00 Jason Lewis jle...@packetnexus.com: I can't find any info related to dates anywhere. jas

Timestamp with empty string as a value

Tested on cassandra 2.0.8: I did some minor testing on timestamp field. It seems that you can give an empty string as a value. Honestly I have no clue what should I think of that. I kind of understand that you can give a string with seconds since epoch and null of course. But empty string? cqlsh

Re: Indexes Fragmentation

Hi, I think more information is needed before this question can be answered. In many cases you manage the indexes by yourself. If that breaks, then you have a consistency problem or a bug in your own code. Consistency is tunable (trade off with performance and availability) and bugs can be fixed.

Cassandra JBOD disk configuration

Hi, Let's imagine that I have one keyspace with one big table configured with size tiered compaction strategy and nothing else. The disk configuration would to have 10x 500GB disks, each mounted to separate directory. Each directory would then be configured as a separate entry in cassandra.yaml.

Re: Help with batch renaming legacy sstable files

Also, did you get to upgrade first to 1.1.x and and then to 1.2.x? That might smoothen the process. Hannu On 26.6.2014, at 9.04, Jens Rantil jens.ran...@tink.se wrote: Hi Todd, Maybe the rename command line utility could help you? Cheers, Jens — Sent from Mailbox On Thu, Jun

Re: Opscenter Entreprise work without licence ?

Hi, It should work without license code or anything of that sort but of course you need a license in production. Hannu On 24.1.2014, at 16.25, Bonnet Jonathan. jonathan.bon...@externe.bnpparibas.com wrote: Nobody to give an answear ?, perhaps i said something stupid :). I Want just a

Re: Help on Designing Cassandra table for my usecase

To my eye that looks something what the traditional analytics systems do. You can check out e.g. Acunu Analytics which uses Cassandra as a backend. Cheers, Hannu 2014/1/9 Naresh Yadav nyadav@gmail.com Hi all, I have a use case with huge data which i am not able to design in cassandra.

Re: Cassandra client alternatives to mimic Couchbase sharding ???

Hi, DataStax Cassandra Java Driver has the possibility to choose the coordinator node based on the partition key (TokenAwarePolicy), however that probably does not solve the consistency problem you are thinking about: http://www.datastax.com/dev/blog/ideology-and-testing-of-a-resilient-driver If

Re: Cassandra client alternatives to mimic Couchbase sharding ???

for request 1 and then written to replication node 2 for request 2. This normally isn’t an issue unless the time drift across the cluster the time between 2 writes for the same row key. Brent From: Hannu Kröger hkro...@gmail.com Reply-To: user@cassandra.apache.org user@cassandra.apache.org Date

Re: Upgrading 1.1 to 1.2 in-place

Hi, Random Partitioner + VNodes are a supported combo based on DataStax documentation: http://www.datastax.com/documentation/cassandra/1.2/webhelp/cassandra/architecture/architecturePartitionerAbout_c.html How else would you even migrate from 1.1 to Vnodes since migration from one partitioner to

Re: help on backup muiltinode cluster

One typical reason is to protect against human error. On 7.12.2013, at 11.09, Jason Wee peich...@gmail.com wrote: Hmm... cassandra fundamental key features like fault tolerant, durable and replication. Just out of curiousity, why would you want to do backup? /Jason On Sat, Dec 7,

Re: Stack trace from a node during a repair

Hi, Are you running nodetool or cassandra as root? I think it doesn't really matter what user is running the nodetool. Those directories should be writable by the user who is running the actual cassandra process. Hannu 2013/12/3 John Pyeatt john.pye...@singlewire.com Then my issue must be

Re: Uneven effective ownership

Hello Katriel, Are you using replication factor 3? So it seems that in us-east it's all fine with each machine having 100% of the data. The problem is in eu-west where you have unbalanced nodes. You should rearrange the tokens in that eu-west DC. Check e.g. this token calculator to calculate

Re: Bad Request: No indexed columns present in by-columns clause with Equal operator?

'); But it doesn't run and I always get error as - Bad Request: No indexed columns present in by-columns clause with Equal operator Any thoughts what wrong I am doing here? On Sun, Nov 3, 2013 at 12:43 PM, Hannu Kröger hkro...@gmail.com wrote: Hi, You cannot query using a field

Re: Bad Request: No indexed columns present in by-columns clause with Equal operator?

Hi, You cannot query using a field that is not indexed in CQL. You have to create either secondary index or create index tables and manage those indexes by yourself and query using those. Since those keys are of high cardinality, usually the recommendation for this kind of use cases is that you

Re: Add a new node

Hello, No you don't need to. Check this out: http://www.datastax.com/documentation/cassandra/2.0/webhelp/index.html#cassandra/operations/ops_add_node_to_cluster_t.html Cheers, Hannu 2013/10/10 juwg j...@jnshangjie.com ** Hi all, I want to ask a basic question: To add a new node to

Re: Re: Add a new node

keyspace, can I change the number of replicas in it's REPLICATION option? If so, do I need to restart the whole cluster? Thanaks in advance. ju wenguang *From:* Hannu Kröger hkro...@gmail.com *Date:* 2013-10-10 16:10 *To:* user user@cassandra.apache.org; juwg j...@jnshangjie.com *Subject

Re: Help on Cassandra Limitaions

) cannot have more that 2 billions thrift columns'. -- Sylvain On Fri, Sep 6, 2013 at 7:55 AM, Hannu Kröger hkro...@gmail.com wrote: I asked the same thing earlier and this is what patrick mcfadin replied: It's not worded well. Essentially it's saying there is a 2B limit on a row. It should

Re: Help on Cassandra Limitaions

I asked the same thing earlier and this is what patrick mcfadin replied: It's not worded well. Essentially it's saying there is a 2B limit on a row. It should be worded a 'CQL row' I hope helps. Cheers, Hannu On 6.9.2013, at 8.20, J Ramesh Kumar rameshj1...@gmail.com wrote: Hi,

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