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Questions tagged [cassandra-2.0]

Cassandra 2.0 is a NoSQL database sponsored by Apache.

Cassandra 2.0 is a NoSQL database sponsored by Apache.

Cassandra advertises itself to have the following merits:

  1. Proven (used by many large established companies);
  2. Performant (peforms consistently well on NoSQL benchmarks);
  3. Fault tolerant (data is automatically replicated to multiple nodes for fault-tolerance. Replication across multiple data centers is supported. Failed nodes can be replaced with no downtime.);
  4. Decentralized (there are no single points of failure and no network bottlenecks. Every node in the cluster is identical);
  5. Durable (durability is the property that writes, once completed, will survive permanently, even if the server is killed or crashes or loses power.); and
  6. Elastic (read and write throughput both increase linearly as new machines are added, with no downtime or interruption to applications);
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Nested query not working in Cassandra

USE users_tracking; SELECT user_name FROM visits where port_name IN (SELECT port_name FROM ports where location = 'NY' )//as temp; It gives an error mismatched input 'SELECT' expecting RULE_T_R_PAREN Is there any way I can store the inner query…
pizzaEatingGuy
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ResponseError : Expected 4 or 0 byte int

I am trying cassandra node driver and stuck in problem while inserting a record, it looks like cassandra driver is not able to insert float values. Problem: When passing int value for insertion in db, api gives following error: Debug: hapi,…
Gaurav Gupta
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high and low cardinality in Cassandra

I keep coming across these terms: high cardinality and low cardinality in Cassandra. I don't understand what exactly they mean. what effects they have on queries and what is preferred. Please explain with example since that will be be easy to…
eagertoLearn
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Consistency Level of Cassandra Lightweight transactions

I read about Cassandra 2's lightweight transactions. Is the consistency level of such a write always at QUORUM? Would this mean that even if I have a multi data center setup with 100s of nodes, then quorum of the entire cluster (majority of the…
vishr
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What is the right way to use Cassandra driver from a web application

I want to build a RESTful API with Java and Cassandra 2.x (on Jersey framework). I'm new to both technologies so I would like to ask you is that the correct way to integrate and share Cassandra driver. 0. Get the driver though Maven …
Lukasz Kujawa
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Cassandra num_tokens - is this really num_token_partitions?

I am new to Cassandra. I am reading about the num_tokens parameter for virtual nodes in the cassandra.yml file. I don't think I quite understand what this is doing or how tokens/partitions are assigned. What is really going on here? The default…
sat
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Is Cassandra for OLAP or OLTP or both?

Cassandra does not comply with ACID like RDBMS but CAP. So Cassandra picks AP out of CAP and leaves it to the user for tuning consistency. I definitely cannot use Cassandra for core banking transaction because C* is slightly inconsistent. But…
Suhas Chandramouli
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Spark Submit fails with java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

I am using spark 1.3.1 prebuild version spark-1.3.1-bin-hadoop2.6.tgz Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less; at …
mithra
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Efficient modeling of versioned hierarchies in Cassandra

Disclaimer: This is quite a long post. I first explain the data I am dealing with, and what I want to do with it. Then I detail three possible solutions I have considered, because I've tried to do my homework (I swear :]). I end up with a "best…
Olivier Lance
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Hive Query Execution Error, return code 3 from MapredLocalTask

I am getting this error while performing a simple join between two tables. I run this query in Hive command line. I am naming table as a & b. Table a is Hive internal table and b is External table (in Cassandra). Table a has only 1610 rows and Table…
user3517633
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Modeling many-to-many relations in Cassandra 2 with CQL3

What is the canonical way to model many-to-many relations with CQL3 ? Let's say I have to tables CREATE TABLE actor ( id text PRIMARY KEY, given text, surname text, ) CREATE TABLE fan ( id text PRIMARY KEY, given text, …
Marco Righele
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How to use cassandra Stress tool

I would like learn more on cassandra stress tool , like how I can do the stress test and study the result. When cassandra-stress is executed from the cmd where is the keyspace made ,How to view them ?
drusya
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modelling cassandra tables for upsert and select query

I have designed following table to store server alarms: create table IF NOT EXISTS host_alerts( unique_key text, host_id text, occur_time timestamp, clear_time timestamp, last_occur timestamp, alarm_name text, primary key…
kinkajou
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What are best practices for backing up a cassandra cluster?

I have a cassandra cluster with ~20 nodes in multiple datacenters. I want to back up the cassandra database. I want it to be possible to restore the backup to a new cluster even if every node in the existing one is simultaneously hit by a…
Andrew
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Cassandra control SSTable size

Is there a way I could control max size of a SSTable, for example 100 MB so that when there is actually more than 100MB of data for a CF, then Cassandra creates next SSTable?
RRM
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