what do you use cassandra for

What are the major mistakes developers make in building a Cassandra database?

How big of a partition can Cassandra handle?

Why does Cassandra fail?

Why is it important to understand the design criteria of a distributed database?

How to make a cluster linearly scalable?

What is secondary index?

Does Cassandra have a secondary index?

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database - When NOT to use Cassandra? - Stack Overflow

There has been a lot of talk related to Cassandra lately. Twitter, Digg, Facebook, etc all use it. When does it make sense to: use Cassandra, not use Cassandra, and use a RDMS instead of Cassandra.

When to use Cassandra and when to steer clear | by Alex Bekker ...

“But Cassandra doesn’t do it well!” is definitely not something you want to hear after deploying a Cassandra cluster and getting down to work with it. Before making any investments, let’s check…

The Top 10 Reasons to Use Cassandra - DevOps.com

The Apache Cassandra database is the right choice of database if you are looking for scalability and high availability without compromising performance for your mission-critical applications. Additionally, Cassandra’s support for replicating across multiple data centers is best-in-class, providing lower latency for users and the peace of mind of knowing that you can survive regional outages.

Top 10 Reasons to Use Cassandra Database - DZone Database

The Apache Cassandra database is the right choice of database if you are looking for scalability and high availability without compromising performance for your mission-critical applications ...

Cassandra Use Cases | When to Use Cassandra Use Cases? | FAQ - EDUCBA

Introduction to Cassandra Use Cases. The Cassandra uses cases is defined as, it is the best acceptable platform where the fewer secondary indicator is needful, which have easy framework and maintenance with the specific speed of interpretation, wide column necessity, and Cassandra can be utilized for various types of applications such as in messaging in which it can be favored for the ...

Why is Cassandra always on?

Thanks to data replication, Cassandra fits ‘always-on’ apps because its clusters are always available . Data is stored on multiple nodes and in multiple data centers, so if up to half the nodes in a cluster go down (or even an entire data center), Cassandra will still manage nicely.

What is Cassandra used for?

It stores data on what movies, games, articles or songs a user has watched, played, read or listened to, how much time they spent on each activity, etc. Then, Cassandra can feed this data to an analytical tool to recommend other movies, games, articles or songs users may like.

Is Cassandra good for sensor data?

The way Cassandra’s data model is organized and the fact that Cassandra is designed for intensive write workloads make it exceptionally good for sensor data. It suits completely different industries, be it manufacturing, logistics, healthcare, real estate, energy production, agriculture or whatever.

Is Cassandra good for data distribution?

Cassandra is by nature good for heavy write workloads. Inter-node data distribution is quick, writes are cheap, which makes Cassandra’s handling hundreds of thousands of write operations per second just a regular Tuesday. Besides, Cassandra handles heavy read workloads very nicely, although there are some limitations described further on.

Is Cassandra a silver bullet?

Cassandra is not a silver bullet, just like any NoSQL database isn’t. It has its own advantages and disadvantages to consider. If you want to check how well you remember them, here’s a mini quiz to take:

Does Cassandra go well with ACID?

Although Cassandra doesn’t go well with transfers between bank accounts and poorly gets along with ACID transactions, banks still can benefit from it. Their big data solutions built to analyze customer data can provide an extra level of security for their clients by enabling fraud detection.

Does Cassandra require data updates?

Messaging systems (chats, collaboration and instant messaging apps, etc.) are just as perfect for Cassandra as sensor data, since they don’t require data updates. Cassandra quickly writes new incoming messages, allows quick reads and other additional features.

What can you do with Cassandra?

Well, to answer this, let’s understand a typical requirement of a large-scale enterprise towards a database management system. Listing their general requirement majorly suffice on:

Who is the right audience for learning Cassandra technologies?

It is for everyone. Anyone who is interested to learn the NoSQL database is welcome to learn this smart technology . People involved in database designing , people involved in handling big data, database designers, developers are open to learning this technology.

How will this technology help you in career growth?

This technology is growing rapidly and is in demand quite high. Even big organizations are coming forward to use and deploy this technology for their business requirements.

What is Cassandra database?

Cassandra is an open-source database application from Apache, which doesn’t require SQL to fetch, view, update, delete the database or the data. Hence it is known as a NoSQL type of database application. This database can be accessed and administered from various nodes both remotely and directly. It is popular for its exclusive features like higher performance, flexibility for expansion and scalability, lower user latency, peer to peer architecture, no-schema for structuring, very less effort and the cost is required for maintenance, faster processing, easy to learn & work on it, uncomplicated process for data copying, etc.

What is commodity server?

Well, in simple words, a Commodity Server is already available computing nodes or components for parallel computing. These Commodity Servers generally involves in Commodity computing; many also know it as commodity cluster computing.

What skills are needed to be a Cassandra developer?

Conceptual skills required. A few of the major but drastically important tech skills required to be a good Cassandra developer is: Concept of database. Knowledge of NoSQL database.

What is peer to peer architecture?

Peer to peer architecture: It does not follow a typical master-slave concept but follows peer-to-peer architecture where each and every node participates equally with equal responsibilities. As a consequence of this, there is no single point of failure. High availability: Since there is no single point of failure, ...

What are the tools that can be integrated into Cassandra?

Apache Spark, a Big Data analytics engine, also has been plugged into work on existing a Cassandra database. There are entire suites of tools that can be integrated or bolted on to Cassandra to increase its capabilities. These include things like Apache Mahout, Kafka, and Zipkin just to name a few. This is important because the more tools you have available to you, the more powerful your data becomes. You also have the ability to gain more insight into your data without having to build and maintain the application systems that were previously required.

What is Cassandra used for?

Analytics companies are using Cassandra to store web analytics data. Medical companies are using Cassandra to store sensor data and other time series inputs. There are also many companies making use of Cassandra for storing IoT data. 6.

Why use Apache Cassandra?

The Apache Cassandra database is the right choice of database if you are looking for scalability and high availability without compromising performance for your mission-critical applications. Additionally, Cassandra’s support for replicating across multiple datacenters is best-in-class, providing lower latency for users and the peace of mind of knowing that you can survive regional outages. To that end, we’ve compiled a list of the top 10 reasons why enterprises onboarding and deploying mission-critical applications should use Cassandra (Apache Cassandra, DataStax Enterprise).

Why is Cassandra the best tool?

There are many reasons that Cassandra could be the right tool for your application. Knowing your systems requirements, workloads, and future will help you make the right choice.

Why is Cassandra important?

This is important because software is always about people. The more of them that you can interact with that have shared your experiences, the better. It will also be easier to find solutions to your problems having a network of people who might have faced them before.

What are the components of Cassandra?

But there are also two often overlooked components that Cassandra provides: data variety and data complexity . Data variety is an alternate way of saying that data coming into one database can come in different forms.

Is Cassandra a masterless system?

Cassandra is a straightforward system to administer. With Cassandra being a masterless system, all nodes in the ring are the same; a homogenous system. It’s fault-tolerant and can support the temporary loss of nodes with minimal impact on production performance.

What is SS table in Cassandra?

Another interesting concept in Cassandra is compaction. “Shut down all the garbage mashers on the detention level!” In a nutshell: the information in your keyspace is stored in a sort of cache called a memtable. When a memtable becomes too large, Cassandra will automatically perform data compaction and ‘flush’ your info into something called an SS Table. This is a static file, a snapshot of your db information. This happens frequently*, and so when you query information from your keyspace, odds are Cassandra is sifting through these SS tables to find the information you seek.

What is load balancer in VM?

A load balancer is a barebones service that runs on its own vm, and its job is to receive connection requests and decide how to route them to your service.

How much RAM do I need for EC2?

You are going to need at least two cores && 8GB of RAM, as per Apache’s documentation. Realistically, if you plan on running this db in any sort of production environment, you’ll need much more. I used several Amazon m5a.large instances and it felt great.

How many nodes are there in Cassandra?

Since then, each instance of Cassandra has evolved to contain 256 nodes (or vnodes). Yet you still have loads of folks referring to instances as nodes. Now you know.

Can you start Cassandra before modifying a YAML file?

Now, you can start Cassandra. You can technically start Cassandra before modifying your yaml file, but configuring first is much simpler and will help you avoid multiple potential pitfalls.

Does Cassandra have multiple VMS?

Because a Cassandra database (or ring) should comprise multiple vms, but by default Cassandra has no idea how or where to look for other servers (or nodes if you are an old-timey yahoo) to include in your cluster. You need to create as many EC2 instances as you would like servers in your cluster.

How to login to Cassandra?

You can now login by typing ‘cqlsh’ in the command line (cqlsh is the command line shell for interacting with Cassandra).

Common Apache Cassandra use cases

Let’s examine the advantages that make Cassandra one of the most widely used NoSQL databases.

Notable Cassandra use cases in action

With so many prominent companies using Apache Cassandra, it’s highly likely we all interact with it in some way multiple times a day. For example, the next time you go for a jog and queue up your Spotify playlist, you’re using an application built on top of Cassandra.

Explore how Cassandra can help your company

Leading companies around the world, ranging from social media to international banking, are using Cassandra for all kinds of use cases.

What is Cassandra data modeling?

Cassandra data modeling is a way to optimize your data model for Cassandra, a database management system. The Cassandra data model is unique because users model the data to fit specific data requests rather than organize relations or objects. Using the model, you can structure data storage as a set of rows organized into tables or columns. The major components of the model are:

Why is Cassandra so expensive?

This can quickly become time-consuming and increase latency variation. Because of how Cassandra stores rows, it can also be costly to read from multiple partitions, even if it's only on a single node. For this reason, aim to read rows from fewer partitions when you issue your read queries.

What is partition in Cassandra?

A partition refers to a group of rows with the same partition key. Your partitions may reside in different nodes, and the partition read you request might require a unique command for each partition in each separate node. This can quickly become time-consuming and increase latency variation. Because of how Cassandra stores rows, it can also be costly to read from multiple partitions, even if it's only on a single node.

What is data modeling in Cassandra?

Data modeling in Cassandra is query-driven, meaning it can be helpful to structure the data in your model around use patterns and planned queries. Try to consider your query patterns before you design your column families.

Why is data modeling important?

Data modeling is a useful tool for organizing and structuring large amounts of data so that you can analyze entities and their relationships. The data model you choose depends on the type of data you need to access and your query patterns. When using the Cassandra data management system, the data model you choose can be especially important. In this article, we discuss what Cassandra data modeling is, when to use it and best practices you can follow to help you design a successful model that works well with Cassandra.

Why is Cassandra still available?

Availability: Cassandra is highly available and can still work even with faults because of the way data replicates across nodes in a cluster. Communicability: Peer-to-peer architecture allows all of the nodes in a Cassandra cluster to communicate with one another.

Why is Cassandra important?

Cassandra is designed to support large amounts of structured or semi-structured data across general servers and shouldn't cause widespread system malfunction because of a single fault. This can be beneficial to companies scaling up because the platform's strength increases with the addition of new data centers, regardless of their location.

How to execute CQL query?

You can execute CQL queries using the execute () method of Session class. Pass the query either in string format or as a Statement class object to the execute () method. Whatever you pass to this method in string format will be executed on the cqlsh.

How to check if an emp table has been deleted?

Use the Describe command to verify whether the table is deleted or not. Since the emp table has been deleted, you will not find it in the column families list.

What is Cassandra cluster?

Cassandra database is distributed over several machines that operate together. The outermost container is known as the Cluster. For failure handling, every node contains a replica, and in case of a failure, the replica takes charge. Cassandra arranges the nodes in a cluster, in a ring format, and assigns data to them.

What does Cassandra do?

In Cassandra, one or more of the nodes in a cluster act as replicas for a given piece of data. If it is detected that some of the nodes responded with an out-of-date value, Cassandra will return the most recent value to the client. After returning the most recent value, Cassandra performs a read repair in the background to update the stale values.

What is Cassandra replication?

Cassandra implements a Dynamo-style replication model with no single point of failure, but adds a more powerful “column family” data model . Cassandra is being used by some of the biggest companies such as Facebook, Twitter, Cisco, Rackspace, ebay, Twitter, Netflix, and more.

Why is Cassandra so popular?

Features of Cassandra. Cassandra has become so popular because of its outstanding technical features. Given below are some of the features of Cassandra: Elastic scalability − Cassandra is highly scalable; it allows to add more hardware to accommodate more customers and more data as per requirement.

What is a NoSQL database?

A NoSQL database (sometimes called as Not Only SQL) is a database that provides a mechanism to store and retrieve data other than the tabular relations used in relational databases. These databases are schema-free, support easy replication, have simple API, eventually consistent, and can handle huge amounts of data.

What is the best way to use NoSQL?

The general idea of NoSQL is that you should use whichever data store is the best fit for your application. If you have a table of financial data, use SQL. If you have objects that would require complex/slow queries to map to a relational schema, use an object or key/value store.

What social media sites use Twitter?

Twitter, Digg, Facebook, etc all use it.

Does Cassandra have consistency?

Cassandra also apparently lets you specify your consistency requirement at query time, which may be a useful compromise for some use cases

Is Cassandra based on NoSQL?

Since Cassandra is based on the NoSQL family of databases, it's important you understand why use a NoSQL database before I answer your questions.

What is Redis used for?

Redis is built to provide In-Memory search for varieties of data structures like trees, queues, linked lists, etc and can be a good fit for making real-time leaderboards, pub-sub kind of system. Similarly there are other databases in this category (Including Cassandra) which are fit for different problem statements.

Is Cassandra partition tolerant?

Cassandra is an available, partition-tolerant system that supports eventual consistency. For more information see this blog post I wrote: Visual Guide to NoSQL Systems.

Does Cassandra have an ACID?

Cassandra is based on a NoSQL database and does not provide ACID and relational data properties. If you have a strong requirement for ACID properties (for example Financial data), Cassandra would not be a fit in that case. Obviously, you can make a workaround for that, however you will end up writing lots of application code to simulate ACID properties and will lose on time to market badly. Also managing that kind of system with Cassandra would be complex and tedious for you.

What are the major mistakes developers make in building a Cassandra database?

Another major mistake developers make in building a Cassandra database is making a poor choice for partition keys.

How big of a partition can Cassandra handle?

Keep data you want to retrieve in single read within a single partition. Don’t let partitions get too big. Cassandra can handle large partitions >100 Megabytes but its not very efficient. Besides, if you are getting partitions that large, it’s unlikely your data distribution will be even.

Why does Cassandra fail?

Cassandra projects tend to fail as a result of one or more of these reasons: The wrong Cassandra features were used. The use case was totally wrong for Cassandra. The data modeling was not done properly.

Why is it important to understand the design criteria of a distributed database?

When dealing with distributed databases, it’s also very important to recognize how the data and workload will be distributed. Without understanding the design criteria, implementation and distribution plan, any attempt to use a distributed database like Cassandra is going to fail. Usually in a spectacular fashion.

How to make a cluster linearly scalable?

Linearly scalable by simply adding more nodes to the cluster.

What is secondary index?

Secondary indexes: They have their uses but not as an alternative access path into a table.

Does Cassandra have a secondary index?

To be honest, it doesn’t help that Cassandra has a bunch of features that probably shouldn’t be there. Features leading one to believe you can do some of the things everyone expects a relational database to do: Secondary indexes: They have their uses but not as an alternative access path into a table.