Apache Cassandra is an open source distributed database management system. It is designed to handle very large amounts of data spread out across many commodity servers while providing a highly available service with no single point of failure. It is a NoSQL solution.

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Why does Cassandra recommend against creating an index on high-cardinality columns?

The Cassandra documentation states, Do not use an index in these situations: On high-cardinality columns because you then query a huge volume of records for a small number of results. See ...
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16 views

Add new data center in EC2 [on hold]

I have 3 node local data center I'm using PropertyFileSnitch, and have 1 node in EC2 using Ec2MultiRegionSnitch, and set topology Manuel when run dsetool status in each data center I get that. local ...
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18 views

Cassandra filtering multiple items

I am attempting to learn Cassandra by taking my RDBMS database and create a nosql version of it. Forgive any mistakes I am just making a quick example so I can ask my question. Here is my ...
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1answer
7 views

Cassandra one-to-many table design

I am new to Cassandra from 20 years of RDBMS, and over the last few days have been reading and watching everything I can get my hands on that applies to my situation. I'm sure this is a basic ...
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1answer
18 views

How to predict new node allocation in a Cassandra cluster?

I have a 5-node Cassandra cluster. Each node has disk space of 5TB. The real usage for each node is around 2.5TB depending on allocations and compactions (some are around 2TB some around 2.8). I ...
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28 views

Slow select from one billion rows GreenPlum DB

I've created the following table on GreenPlum: CREATE TABLE data."CDR" ( mcc text, mnc text, lac text, cell text, from_number text, to_number text, cdr_time timestamp ...
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1answer
49 views

Migration from Cassandra 2.x to 3.x: schema_keyspaces table is gone. How do you query system keyspaces?

I just migrated from Cassandra 2.x to 3.x (specifically, 3.4). Now the system tables have completely changed, and these changes are not in the documentation. If you look at the current CQL docs for ...
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8 views

Cassandra Multi Datacenter Different Data Size

I have a cassandra cluster which consists of 2 datacenter. datacenter2 is only for live backup and added existing cluster for this purporse. After run rolling repair on each node, nodetool status ...
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6 views

Is making a recursive hard link of all files inside cassandra data file directory a safe way to back up the entire database?

I have a single node cassandra cluster running on my local machine. I want to back up my data file directory. My question is pretty simple. Say I was to search the entire data file directory and ...
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26 views

Cassandra cluster monitoring linux script

I have opscenter but I am also looking for having a Cassandra cluster monitoring script running locally on the cluster nodes. Simple "nodetool status" would be fine. Does anyone have a handy script ...
0
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1answer
18 views

how to disable delete in replication Cassandra datastax

my previous scenario i used Sql server one instance in amazon for live and the second in local network for archiving by disable delete in replication can i do this in Cassandra or what best ...
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26 views

How to create multiple graphs with titanDB(+cassandra , +rexster) in the same machine?

I'm experimenting with TitanDB (with Cassandra as storage) + Rexter. I have used different storage.keyspace value for different graphs in Titanrexster-server.xml thn also i m not getting multiple ...
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31 views

Cassandra in a Public Cloud - Which Snitch?

I am planning on deploying Cassandra in a public cloud (like Amazon AWS). The cluster will span multiple zones and regions. The cluster will also require logical DC separation within a given region. ...
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23 views

Cassandra DB Schema for Article, Comment on Comment

What is the efficient way to store the comments on comments in Cassandra so that retrieval will be easy(just through the partition key) e.g. There is article and people can comment on that article. ...
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42 views

Appropriate Design For Notification System

I am using Cassandra to store a list of notifications that have been sent to a user. The few requirements I have are: Order the notifications for each user by time received (DESC) Be able to delete ...
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43 views

How to get Cassendra database dump with data

I need to get a dump(with data) from a remote Cassandra database. I was able to get database schema via following command. How can i get all data in the keyspace? I'm using Cassandra 1.1.9. echo -e ...
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2answers
436 views

NoSQL : What is unstructured data?

we are currently running at the edge of resources with our mssql server based solution. We have now many traditional options regarding the next move to tackle the load: buy faster CPUs and IO ...
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1answer
56 views

Filter rows, but only select most recent row for each Id

I have some code that is processing a lot of tasks. These tasks are either connected to a user or an account. Each Task go through many statuses -> Queued, Started, Error, Postponed, Queued, Started, ...
2
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1answer
171 views

How does the Cassandra distribute data?

I cannot find a detailed document on this anywhere, however, that being said, if anyone has an answer to my question, I would be extremely grateful. In regards to Cassandra's standard node ...
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2answers
107 views

Cassandra cluster monitoring

We using Nagios for our servers monitoring. Each web-environment have 1 cluster as backend - Cassanra 2.0. Each cluster have 3-5 nodes. Question is: I want write a plugin for Nagios, for Cassandra's ...
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1answer
89 views

How to Query Properties of an Entity in Apache Cassandra

I am new to Apache Cassandra, and I would like to know how to create a table in which I can filter rows by non-key columns. In relational databases, I would simply create a table with an ID as a ...
1
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1answer
64 views

cassandra in memory tables

I am planning to use Cassandra in memory tables for my particular work load. THe problem is I am worried if the node fails then what will happen to the data in memory that was not flushed to disk ? ...
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1answer
164 views

A good dataset to experiment NoSQL databases [closed]

I need to do some experiments in HBase and Cassandra and to do that I need an adequate dataset. The dataset I'm looking for has to be large enough (i.e. more than 2GB) and the data in it has to be ...
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130 views

Cassandra Database limitation

why Cassandra is limited to 65535 records only when stored in batch and loop is encounters 20000 only? I have inserted 20,000 customers but it shows an error like too many values for built statement, ...
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19 views

Running Cassandra on Encypted filesystem

Looking for pointers for running Cassandra on a Linux File system encrypted by open source tools. Will this satisfy "data-at-rest" encryption ? Is the encryption transparent to Cassandra DB ...
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110 views

What kind of database is Cassandra DB?

I was taking some courses to understand better the way Cassandra works (at academy.datastax.com) and by what I gathered it came to me that it is a Key Value Database because of the way it stores data ...
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90 views

Cassandra - save file

I'm new with Cassandra, and even more - I never have such task for habitual RDMS systems, like MariaDB or Oracle. So, how can I store file in to Cassandra's table? Preferably using Python-driver, but ...
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1answer
74 views

How Wide-columns databases achieve dynamic columns on the storage layout? [closed]

As known, in relational databases, when adding a new column, data must be reallocated (http://stackoverflow.com/questions/463677/alter-table-without-locking-the-table) to maintain a single row ...
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59 views

Update a Record in Cassandra

I'm having the following query while updating a particular record. I've a user Column Family CF as follow:- class User(Model): user_id = UUID(default=uuid.uuid4,primary_key= True) date = ...
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42 views

Cassandra- Data modelling for UserProfilie [closed]

I've a user model, having attributes as follow:- class User(Model): user_id = columns.Integer(primary_key=True) username = columns.Text() email = columns.Text() fname = columns.Text() ...
3
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1answer
1k views

Modeling Graph Data in Cassandra DB

I want to use Apache Cassandra to store a large amount of graph data according to a property graph model. The model contains the following entities: Vertices: Contains a map of key/value pairs ...
0
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1answer
585 views

What is the Cassandra setting for coordinator timeouts for schema change queries?

In my testing, I've found that the write_request_timeout_in_ms setting does not have any bearing on the timeouts for CREATE TABLE or ALTER TABLE statements in CQL. For instance, I have it set to ...
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1answer
292 views

Cassandra: memtable_offheap_space_in_mb and memtable_cleanup_threshold

I use C* v2.1.2 do write only workload (into one column family) and experiment with offheap-objects memtable space. I set parameters to: memtable_offheap_space_in_mb = 51200 # 50Gb ...
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1answer
159 views

Database migration for Large Data Set from MySQL to NoSQL

I have an existing APP that has N types of products that is normalized with MySQL. Each types of products have over 500K skus, and one of them are in the in 2M currently. We are currently tracking on ...
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1answer
2k views

Cassandra row ordering best practice

I have a column family that store articles. I'll need to get those articles from the most recent to the oldest, getting them from Country, and of course the ability to limit the number of fetched ...
2
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1answer
540 views

Upgrading Cassandra from 1.1.0 to latest

I have a single node cassandra database running since 2 years now... never had any issues with it, but I would like to upgrade it to the latest cassandra (2.1.2 at the time I write those lines), of ...
2
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49 views

Cassandra Deployement Architecture

I'm new to Cassandra. I have the responsibility to design a basic deployment architecture for a use case. I'd like to know if my solution is correct, and get advice and recommendations from you. Here ...
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2answers
2k views

Do you have to run nodetool repair on every node?

Do you have to run nodetool repair on every node in a cluster, or do you only need to run it on one node, and from there Cassandra will take care of the rest?
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1answer
188 views

Date model for commenting system stored in a key-value NoSQL DB?

I'm trying to leverage Cassandra's strong support for time series data to build a commenting system. So far I'm thinking that each row would be a particular topic, and each comment would be a new ...
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1answer
3k views

Small startup: Cassandra + Hadoop or ElasticSearch

To give some context, I am from a small start up (4 team members) and we work in the education space. We've developed an e-learning platform that several schools are already using. We currently have ...
2
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1answer
186 views

Keeping rows ordered by counter value

I'm storing linked words in a Cassandra v2 cluster and I'm having a hard time doing efficient reads. I'm trying to fetch the top X rows with the highest counter value. Cassandra doesn't store the ...
0
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1answer
1k views

Allow filtering not working as expected

I'm having issues with getting ALLOW FILTERING to work. In our Cassandra 1.2 database, we have a table like this: CREATE TABLE some_table partition_key text, other_key text, non_key ...
2
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2answers
1k views

Cassandra: maintenance

I am inexperienced with Cassandra, but I have some experience with SQL-based relational databases. I have been unable to find best practices information about how to maintain Cassandra once deployed. ...
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1answer
1k views

How can I get nodetool without Cassandra

I have Cassandra pool across machines in LAN. I need nodetool on machine without Cassandra installed. How can I get it? Is the installing Cassandra and disabling db service is the best way?
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1answer
875 views

Cassendra schema design suggestion for chat archive

I have gone though this article and here is the schema I have got from it. This is helpful for my application for maintaining statuses of a user, but how can extend this to maintain one to one chat ...
0
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1answer
141 views

Upgrading Cassandra

my Cassandra version is 1.2.4 and i'm trying to upgrade it to 2.0.5 and i know that in the first part i have to upgrade it to 1.0.14 and after that try to upgrade it to the 2.0.5 , when I try to run ...
0
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1answer
149 views

Cassandra with Hadoop

Cassandra uses Cassandra File System (CFS) and Hadoop uses Hadoop Distributed File System (HDFS) I'm already using Pig over HDFS and i would like to install Cassandra. Having additional servers for ...
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2answers
2k views

How to create multiple graphs with TitanDB (+Cassandra) in the same machine?

I'm experimenting with TitanDB (with Cassandra as storage) + Rexter. I've been reading the documentation during hours and trying to create multiple graph DBs on the same machine, but I didn't find ...
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1answer
72 views

Database software advice [closed]

I have this strange question. I'm building a service that stores information into one table. That table has 20 columns. My database will have many billion rows. Right now I'm using Cassandra, but it ...
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2answers
7k views

Is there any open source GUI tool to monitor cassandra? [closed]

I would like to monitor cassandra database as well as need to check the values in the database. Could any one suggest me best open source GUI tool ? Regards, Arun Raj.