cassandra tutorial - Wikitechy https://www.wikitechy.com/interview-questions/tag/cassandra-tutorial/ Interview Questions Mon, 13 Sep 2021 11:44:42 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png cassandra tutorial - Wikitechy https://www.wikitechy.com/interview-questions/tag/cassandra-tutorial/ 32 32 What is the virtual node in Cassandra ? https://www.wikitechy.com/interview-questions/cassandra/what-is-the-virtual-node-in-cassandra/ https://www.wikitechy.com/interview-questions/cassandra/what-is-the-virtual-node-in-cassandra/#respond Tue, 13 Jul 2021 05:40:31 +0000 https://www.wikitechy.com/interview-questions/?p=442

Virtual node in Cassandra:

  • Prior to Cassandra 1.2, every node was allocate to a particular token range.
  • Instead of a node being responsible for one large range of tokens, it is responsible for many smaller ranges.
  • In this way, one physical node is essentially hosting many smaller “virtual” nodes.
  • One of the new features slated for Cassandra 1.2’s release later this year is virtual nodes (vnodes.)
  • Vnodes:
    • If you recall how token selection works currently, there’s one token per node, and a node owns exactly one contiguous range in the ring space.
  • Vnodes modify this paradigm from one token per node to many token per node.
  • Within a cluster these can be randomly selected and be non-contiguous, giving us many smaller ranges that belong to each node.
virtual node in cassandra

Advantages of virtual nodes

  • Tokens are automatically measured and allocate to every node.
  • when adding or removing nodes Re-balancing a cluster is automatically accomplished.
  • When a node merge the cluster, it assumes responsibility for an even portion of data from the other nodes in the cluster.
  • If a node fails, the load is develop evenly across other nodes in the cluster.
  • Number of vNodes can be set as node level.
]]> https://www.wikitechy.com/interview-questions/cassandra/what-is-the-virtual-node-in-cassandra/feed/ 0 What is the use of Cassandra database ? https://www.wikitechy.com/interview-questions/cassandra/what-is-the-use-of-cassandra-database/ https://www.wikitechy.com/interview-questions/cassandra/what-is-the-use-of-cassandra-database/#respond Tue, 13 Jul 2021 05:36:30 +0000 https://www.wikitechy.com/interview-questions/?p=440

Cassandra database:

  • Apache Cassandra is a high-performance provides database to manage large number of data among many commodity servers and then it is highly scalable.
  • It is a type of NoSQL database.
  • Apache Cassandra can be used for different applications.

In activity-tracking and monitoring applications:

  • Numerous entertainment and media organisations use Cassandra to observe user activity based on movies, music, albums, artists or other parameters.

In heavy write systems or in time-series-based applications:

  • Cassandra is best for heavy write systems .For example, data is logged for each request based on hits in web analytics, by type of browser, traffic sources, position, character, technology, tools, etc.

In social media analytics:

  • Cassandra is used by many social media providers to recognize the data and gives recommendations to their users.

In product catalogues and retail applications:

  • A very popular use case of Cassandra is to show fast product catalog inputs and lookup, and in retail applications.

Messaging:

  • Cassandra serves as the database backbone for countless mobile phone and message providers’ applications.
what is the cassandra database

What is the use of Cassandra?

cap theorem
  • Apache Cassandra is a high-performance provides database to manage large number of data among many commodity servers and then it is highly scalable.
Use of apache cassandra
]]> https://www.wikitechy.com/interview-questions/cassandra/what-is-the-use-of-cassandra-database/feed/ 0 What is the replica placement strategy in Cassandra ? https://www.wikitechy.com/interview-questions/cassandra/what-is-the-replica-placement-strategy-in-cassandra/ https://www.wikitechy.com/interview-questions/cassandra/what-is-the-replica-placement-strategy-in-cassandra/#respond Tue, 13 Jul 2021 05:30:15 +0000 https://www.wikitechy.com/interview-questions/?p=438

Data replication:

  • Once you’ve absorbed that the strategy should fit the kind of environment you are placing your cluster in.
  • If you want to stay in one region of Amazon web services? You can either set yourself up as one dc per availability zone (AZ), or you can set up your cluster to use one dc and treat the AZs as racks.
  • Then you can replicate so that if an AZ goes down you won’t have a system problem, just some downed and unavailable servers.
  • If an AZ goes down (or a rack goes down) that all the copies of an important piece of data will be available.
  • You also are stuck with latency issues if you want to cross into a different region.
  • Your data has to replicate into the new region and if you went ‘simplestrategy’ you are going to have massive traffic trying to keep the database in sync.
replica placement strategy in cassandra
]]> https://www.wikitechy.com/interview-questions/cassandra/what-is-the-replica-placement-strategy-in-cassandra/feed/ 0 What is the history of the Cassandra database ? https://www.wikitechy.com/interview-questions/cassandra/what-is-the-history-of-the-cassandra-database/ https://www.wikitechy.com/interview-questions/cassandra/what-is-the-history-of-the-cassandra-database/#respond Tue, 13 Jul 2021 04:45:53 +0000 https://www.wikitechy.com/interview-questions/?p=411

History of the Cassandra database:

  • Amazon’s dynamo and Prashant malik are written by Avinash Lakshman at first succeed Cassandra at Facebook to capable the Facebook inbox search purpose.
  • In July 2008,Facebook published Cassandra as an open-source project on Google code.
  • In March 2009 it develop an Apache incubator project.
  • On february 17, 2010 it qualify to a top-ranking project.
history of database

Releases after graduation include

  • Added help for integrated caching, and Apache Hadoop MapReduce distributed 0.6 in Apr 12 2010.
  • Added secondary indexes and online schema changes distributed 0.7 in Jan 08 2011.
  • Added the Cassandra Query Language (CQL), self-tuning memTables, and help for zero-downtime upgrades distributed 0.8 in Jun 2 2011.
  • Added integrated compression, levelled compaction, and improved read-performance distributed 1.0 in Oct 17 2011,
  • Added self-tuning caches, row-level isolation, and support for mixed ssd/spinning disk deployments distributed 1.1 in Apr 23 2012,
  • Added clustering among virtual nodes, inter-node communication, atomic batches, and request tracing distributed 1.2 in Jan 2 2013,
  • Added lightweight transactions (based on the Paxos consensus protocol), triggers, improved compactions distributed 2.0 in Sep 4 2013,
  • In Sep 10 2014 publish 2.1
  • In July 20, 2015 publish 2.2
  • In November 11, 2015 publish 3.0
  • Monthly publish tick-tock like release model in 3.1 across 3.10. When even-numbered contain both bug fixes and new features while odd-numbered involve bug fixes only.
  • In June 23, 2017 publish 3.11 as a stable and it distributed series and bug fix from the last tick-tock characteristic publish.
history of the cassandra database
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