Download or read book Mastering Apache Cassandra Second Edition written by Nishant Neeraj and published by Packt Publishing Ltd. This book was released on 2015-03-26 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is aimed at intermediate developers with an understanding of core database concepts who want to become a master at implementing Cassandra for their application.

Download or read book Mastering Apache Cassandra 3 x written by Aaron Ploetz and published by Packt Publishing Ltd. This book was released on 2018-10-31 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Build, manage, and configure high-performing, reliable NoSQL database for your applications with Cassandra Key FeaturesWrite programs more efficiently using Cassandra's features with the help of examplesConfigure Cassandra and fine-tune its parameters depending on your needsIntegrate Cassandra database with Apache Spark and build strong data analytics pipelineBook Description With ever-increasing rates of data creation, the demand for storing data fast and reliably becomes a need. Apache Cassandra is the perfect choice for building fault-tolerant and scalable databases. Mastering Apache Cassandra 3.x teaches you how to build and architect your clusters, configure and work with your nodes, and program in a high-throughput environment, helping you understand the power of Cassandra as per the new features. Once you’ve covered a brief recap of the basics, you’ll move on to deploying and monitoring a production setup and optimizing and integrating it with other software. You’ll work with the advanced features of CQL and the new storage engine in order to understand how they function on the server-side. You’ll explore the integration and interaction of Cassandra components, followed by discovering features such as token allocation algorithm, CQL3, vnodes, lightweight transactions, and data modelling in detail. Last but not least you will get to grips with Apache Spark. By the end of this book, you’ll be able to analyse big data, and build and manage high-performance databases for your application. What you will learnWrite programs more efficiently using Cassandra's features more efficientlyExploit the given infrastructure, improve performance, and tweak the Java Virtual Machine (JVM)Use CQL3 in your application in order to simplify working with CassandraConfigure Cassandra and fine-tune its parameters depending on your needsSet up a cluster and learn how to scale itMonitor a Cassandra cluster in different waysUse Apache Spark and other big data processing toolsWho this book is for Mastering Apache Cassandra 3.x is for you if you are a big data administrator, database administrator, architect, or developer who wants to build a high-performing, scalable, and fault-tolerant database. Prior knowledge of core concepts of databases is required.

Download or read book Mastering Apache Cassandra 3 x Third Edition written by Aaron Ploetz and published by . This book was released on 2018-10-31 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Build, manage, and configure high-performing, reliable NoSQL database for your applications with Cassandra Key Features Write programs more efficiently using Cassandra's features with the help of examples Configure Cassandra and fine-tune its parameters depending on your needs Integrate Cassandra database with Apache Spark and build strong data analytics pipeline Book Description With ever-increasing rates of data creation, the demand for storing data fast and reliably becomes a need. Apache Cassandra is the perfect choice for building fault-tolerant and scalable databases. Mastering Apache Cassandra 3.x teaches you how to build and architect your clusters, configure and work with your nodes, and program in a high-throughput environment, helping you understand the power of Cassandra as per the new features. Once you've covered a brief recap of the basics, you'll move on to deploying and monitoring a production setup and optimizing and integrating it with other software. You'll work with the advanced features of CQL and the new storage engine in order to understand how they function on the server-side. You'll explore the integration and interaction of Cassandra components, followed by discovering features such as token allocation algorithm, CQL3, vnodes, lightweight transactions, and data modelling in detail. Last but not least you will get to grips with Apache Spark. By the end of this book, you'll be able to analyse big data, and build and manage high-performance databases for your application. What you will learn Write programs more efficiently using Cassandra's features more efficiently Exploit the given infrastructure, improve performance, and tweak the Java Virtual Machine (JVM) Use CQL3 in your application in order to simplify working with Cassandra Configure Cassandra and fine-tune its parameters depending on your needs Set up a cluster and learn how to scale it Monitor a Cassandra cluster in different ways Use Apache Spark and other big data processing tools Who this book is for Mastering Apache Cassandra 3.x is for you if you are a big data administrator, database administrator, architect, or developer who wants to build a high-performing, scalable, and fault-tolerant database. Prior knowledge of core concepts of databases is required.

Download or read book Learning Apache Cassandra written by Mat Brown and published by Packt Publishing Ltd. This book was released on 2015-02-25 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: If you're an application developer familiar with SQL databases such as MySQL or Postgres, and you want to explore distributed databases such as Cassandra, this is the perfect guide for you. Even if you've never worked with a distributed database before, Cassandra's intuitive programming interface coupled with the step-by-step examples in this book will have you building highly scalable persistence layers for your applications in no time.

Download or read book Cassandra The Definitive Guide written by Jeff Carpenter and published by "O'Reilly Media, Inc.". This book was released on 2016-06-29 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imagine what you could do if scalability wasn't a problem. With this hands-on guide, you’ll learn how the Cassandra database management system handles hundreds of terabytes of data while remaining highly available across multiple data centers. This expanded second edition—updated for Cassandra 3.0—provides the technical details and practical examples you need to put this database to work in a production environment. Authors Jeff Carpenter and Eben Hewitt demonstrate the advantages of Cassandra’s non-relational design, with special attention to data modeling. If you’re a developer, DBA, or application architect looking to solve a database scaling issue or future-proof your application, this guide helps you harness Cassandra’s speed and flexibility. Understand Cassandra’s distributed and decentralized structure Use the Cassandra Query Language (CQL) and cqlsh—the CQL shell Create a working data model and compare it with an equivalent relational model Develop sample applications using client drivers for languages including Java, Python, and Node.js Explore cluster topology and learn how nodes exchange data Maintain a high level of performance in your cluster Deploy Cassandra on site, in the Cloud, or with Docker Integrate Cassandra with Spark, Hadoop, Elasticsearch, Solr, and Lucene

Download or read book Mastering Apache Cassandra written by Nishant Neeraj and published by . This book was released on 2013 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mastering Apache Cassandra is a practical, hands-on guide with step-by-step instructions. The smooth and easy tutorial approach focuses on showing people how to utilize Cassandra to its full potential. This book is aimed at intermediate Cassandra users. It is best suited for startups where developers have to wear multiple hats: programmer, DevOps, release manager, convincing clients, and handling failures. No prior knowledge of Cassandra is required.

Download or read book Mastering Apache Cassandra written by Nishant Neeraj and published by Packt Pub Limited. This book was released on 2013-09 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mastering Apache Cassandra is a practical, hands-on guide with step-by-step instructions. The smooth and easy tutorial approach focuses on showing people how to utilize Cassandra to its full potential.This book is aimed at intermediate Cassandra users. It is best suited for startups where developers have to wear multiple hats: programmer, DevOps, release manager, convincing clients, and handling failures. No prior knowledge of Cassandra is required.

Download or read book Practical Cassandra written by Russell Bradberry and published by Pearson Education. This book was released on 2014 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Eric and Russell were early adopters of Cassandra at SimpleReach. In Practical Cassandra, you benefit from their experience in the trenches administering Cassandra, developing against it, and building one of the first CQL drivers. If you are deploying Cassandra soon, or you inherited a Cassandra cluster to tend, spend some time with the deployment, performance tuning, and maintenance chapters... If you are new to Cassandra, I highly recommend the chapters on data modeling and CQL." -From the Foreword by Jonathon Ellis, Apache Cassandra Chair Build and Deploy Massively Scalable, Super-fast Data Management Applications with Apache Cassandra Practical Cassandra is the first hands-on developer's guide to building Cassandra systems and applications that deliver breakthrough speed, scalability, reliability, and performance. Fully up to date, it reflects the latest versions of Cassandra-including Cassandra Query Language (CQL), which dramatically lowers the learning curve for Cassandra developers. Pioneering Cassandra developers and Datastax MVPs Russell Bradberry and Eric Lubow walk you through every step of building a real production application that can store enormous amounts of structured, semi-structured, and unstructured data. Drawing on their exceptional expertise, Bradberry and Lubow share practical insights into issues ranging from querying to deployment, management, maintenance, monitoring, and troubleshooting. The authors cover key issues, from architecture to migration, and guide you through crucial decisions about configuration and data modeling. They provide tested sample code, detailed explanations of how Cassandra works "under the covers," and new case studies from three cutting-edge users: Ooyala, Hailo, and eBay. Coverage includes Understanding Cassandra's approach, architecture, key concepts, and primary use cases- and why it's so blazingly fast Getting Cassandra up and running on single nodes and large clusters Applying the new design patterns, philosophies, and features that make Cassandra such a powerful data store Leveraging CQL to simplify your transition from SQL-based RDBMSes Deploying and provisioning through the cloud or on bare-metal hardware Choosing the right configuration options for each type of workload Tweaking Cassandra to get maximum performance from your hardware, OS, and JVM Mastering Cassandra's essential tools for maintenance and monitoring Efficiently solving the most common problems with Cassandra deployment, operation, and application development

Download or read book Mastering Spark with R written by Javier Luraschi and published by "O'Reilly Media, Inc.". This book was released on 2019-10-07 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: If you’re like most R users, you have deep knowledge and love for statistics. But as your organization continues to collect huge amounts of data, adding tools such as Apache Spark makes a lot of sense. With this practical book, data scientists and professionals working with large-scale data applications will learn how to use Spark from R to tackle big data and big compute problems. Authors Javier Luraschi, Kevin Kuo, and Edgar Ruiz show you how to use R with Spark to solve different data analysis problems. This book covers relevant data science topics, cluster computing, and issues that should interest even the most advanced users. Analyze, explore, transform, and visualize data in Apache Spark with R Create statistical models to extract information and predict outcomes; automate the process in production-ready workflows Perform analysis and modeling across many machines using distributed computing techniques Use large-scale data from multiple sources and different formats with ease from within Spark Learn about alternative modeling frameworks for graph processing, geospatial analysis, and genomics at scale Dive into advanced topics including custom transformations, real-time data processing, and creating custom Spark extensions

Download or read book Seven NoSQL Databases in a Week written by Xun (Brian) Wu and published by Packt Publishing Ltd. This book was released on 2018-03-29 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: A beginner's guide to get you up and running with Cassandra, DynamoDB, HBase, InfluxDB, MongoDB, Neo4j, and Redis Key Features Covers the basics of 7 NoSQL databases and how they are used in the enterprises Quick introduction to MongoDB, DynamoDB, Redis, Cassandra, Neo4j, InfluxDB, and HBase Includes effective techniques for database querying and management Book Description This is the golden age of open source NoSQL databases. With enterprises having to work with large amounts of unstructured data and moving away from expensive monolithic architecture, the adoption of NoSQL databases is rapidly increasing. Being familiar with the popular NoSQL databases and knowing how to use them is a must for budding DBAs and developers. This book introduces you to the different types of NoSQL databases and gets you started with seven of the most popular NoSQL databases used by enterprises today. We start off with a brief overview of what NoSQL databases are, followed by an explanation of why and when to use them. The book then covers the seven most popular databases in each of these categories: MongoDB, Amazon DynamoDB, Redis, HBase, Cassandra, InfluxDB, and Neo4j. The book doesn't go into too much detail about each database but teaches you enough to get started with them. By the end of this book, you will have a thorough understanding of the different NoSQL databases and their functionalities, empowering you to select and use the right database according to your needs. What you will learn Understand how MongoDB provides high-performance, high-availability, and automatic scaling Interact with your Neo4j instances via database queries, Python scripts, and Java application code Get familiar with common querying and programming methods to interact with Redis Study the different types of problems Cassandra can solve Work with HBase components to support common operations such as creating tables and reading/writing data Discover data models and work with CRUD operations using DynamoDB Discover what makes InfluxDB a great choice for working with time-series data Who this book is for If you are a budding DBA or a developer who wants to get started with the fundamentals of NoSQL databases, this book is for you. Relational DBAs who want to get insights into the various offerings of popular NoSQL databases will also find this book to be very useful.

Download or read book Mastering Apache Cassandra written by Cybellium Ltd and published by Cybellium Ltd. This book was released on 2023-09-26 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unleash the Power of Distributed Database for Scalable and High-Performance Applications Are you ready to explore the world of distributed databases and unlock the potential of Apache Cassandra? "Mastering Apache Cassandra" is your comprehensive guide to understanding and harnessing the capabilities of Cassandra for building scalable and high-performance applications. Whether you're a database administrator seeking to optimize performance or a developer aiming to create resilient data-driven solutions, this book equips you with the knowledge and tools to master the art of Cassandra database management. Key Features: 1. Deep Dive into Cassandra: Immerse yourself in the core principles of Apache Cassandra, understanding its architecture, data model, and distributed nature. Build a solid foundation that empowers you to manage data effectively in distributed environments. 2. Installation and Configuration: Master the art of installing and configuring Cassandra on various platforms. Learn about cluster setup, node communication, and replication strategies for fault tolerance. 3. Cassandra Query Language (CQL): Uncover the power of CQL for interacting with Cassandra databases. Explore data definition, manipulation, and querying using CQL's intuitive syntax. 4. Data Modeling: Delve into effective data modeling for Cassandra. Learn about tables, primary keys, composite keys, and denormalization strategies to optimize data retrieval and storage. 5. Distributed Data Management: Discover techniques for managing distributed data effectively. Explore concepts like consistency levels, replication factor, and data partitioning for maintaining data integrity. 6. Performance Tuning and Optimization: Explore strategies for optimizing Cassandra performance. Learn about compaction, read and write paths, caching, and tuning settings to achieve low-latency responses. 7. High Availability and Failover: Master the art of ensuring high availability in Cassandra clusters. Learn about replication strategies, data repair, and handling node failures to maintain continuous data access. 8. Security and Authentication: Explore security features and best practices in Cassandra. Learn how to implement authentication, authorization, and encryption to protect your data. 9. Batch Processing and Analytics: Uncover strategies for performing batch processing and analytics with Cassandra. Learn how to integrate with tools like Apache Spark and execute complex queries. 10. Real-World Applications: Gain insights into real-world use cases of Cassandra across industries. From e-commerce to finance, explore how organizations are leveraging Cassandra's capabilities for innovation. Who This Book Is For: "Mastering Apache Cassandra" is an indispensable resource for database administrators, developers, and IT professionals who want to excel in managing Cassandra databases. Whether you're new to Cassandra or seeking advanced techniques, this book will guide you through the intricacies and empower you to harness the full potential of distributed data management.

Download or read book Learning Apache Cassandra written by Mat Brown and published by Packt Publishing. This book was released on 2015-02-25 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Apache Cassandra Essentials written by Nitin Padalia and published by Packt Publishing Ltd. This book was released on 2015-11-20 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Create your own massively scalable Cassandra database with highly responsive database queries About This Book Create a Cassandra cluster and tweak its configuration to get the best performance based on your environment Analyze the key concepts and architecture of Cassandra, which are essential to create highly responsive Cassandra databases A fast-paced and step-by-step guide on handling huge amount of data and getting the best out of your database applications Who This Book Is For If you are a developer who is working with Cassandra and you want to deep dive into the core concepts and understand Cassandra's non-relational nature, then this book is for you. A basic understanding of Cassandra is expected. What You Will Learn Install and set up your Cassandra Cluster using various installation types Use Cassandra Query Language (CQL) to design Cassandra database and tables with various configuration options Design your Cassandra database to be evenly loaded with the lowest read/write latencies Employ the available Cassandra tools to monitor and maintain a Cassandra cluster Debug CQL queries to discover why they are performing relatively slowly Choose the best-suited compaction strategy for your database based on your usage pattern Tune Cassandra based on your deployment operation system environment In Detail Apache Cassandra Essentials takes you step-by-step from from the basics of installation to advanced installation options and database design techniques. It gives you all the information you need to effectively design a well distributed and high performance database. You'll get to know about the steps that are performed by a Cassandra node when you execute a read/write query, which is essential to properly maintain of a Cassandra cluster and to debug any issues. Next, you'll discover how to integrate a Cassandra driver in your applications and perform read/write operations. Finally, you'll learn about the various tools provided by Cassandra for serviceability aspects such as logging, metrics, backup, and recovery. Style and approach This step-by-step guide is packed with examples that explain the core concepts as well as advanced concepts, techniques, and usages of Apache Cassandra.

Download or read book Learning Apache Cassandra written by Sandeep Yarabarla and published by Packt Publishing Ltd. This book was released on 2017-04-25 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Build a scalable, fault-tolerant and highly available data layer for your applications using Apache Cassandra About This Book Install Cassandra and set up multi-node clusters Design rich schemas that capture the relationships between different data types Master the advanced features available in Cassandra 3.x through a step-by-step tutorial and build a scalable, high performance database layer Who This Book Is For If you are a NoSQL developer and new to Apache Cassandra who wants to learn its common as well as not-so-common features, this book is for you. Alternatively, a developer wanting to enter the world of NoSQL will find this book useful. It does not assume any prior experience in coding or any framework. What You Will Learn Install Cassandra Create keyspaces and tables with multiple clustering columns to organize related data Use secondary indexes and materialized views to avoid denormalization of data Effortlessly handle concurrent updates with collection columns Ensure data integrity with lightweight transactions and logged batches Understand eventual consistency and use the right consistency level for your situation Understand data distribution with Cassandra Develop simple application using Java driver and implement application-level optimizations In Detail Cassandra is a distributed database that stands out thanks to its robust feature set and intuitive interface, while providing high availability and scalability of a distributed data store. This book will introduce you to the rich feature set offered by Cassandra, and empower you to create and manage a highly scalable, performant and fault-tolerant database layer. The book starts by explaining the new features implemented in Cassandra 3.x and get you set up with Cassandra. Then you'll walk through data modeling in Cassandra and the rich feature set available to design a flexible schema. Next you'll learn to create tables with composite partition keys, collections and user-defined types and get to know different methods to avoid denormalization of data. You will then proceed to create user-defined functions and aggregates in Cassandra. Then, you will set up a multi node cluster and see how the dynamics of Cassandra change with it. Finally, you will implement some application-level optimizations using a Java client. By the end of this book, you'll be fully equipped to build powerful, scalable Cassandra database layers for your applications. Style and approach This book takes a step-by- step approach to give you basic to intermediate knowledge of Apache Cassandra. Every concept is explained in depth, and is supplemented with practical examples when required.

Download or read book Cassandra 3 x High Availability written by Robbie Strickland and published by Packt Publishing Ltd. This book was released on 2016-08-29 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Achieve scalability and high availability without compromising on performance About This Book See how to get 100 percent uptime with your Cassandra applications using this easy-follow guide Learn how to avoid common and not-so-common mistakes while working with Cassandra using this highly practical guide Get familiar with the intricacies of working with Cassandra for high availability in your work environment with this go-to-guide Who This Book Is For If you are a developer or DevOps engineer who has basic familiarity with Cassandra and you want to become an expert at creating highly available, fault tolerant systems using Cassandra, this book is for you. What You Will Learn Understand how the core architecture of Cassandra enables highly available applications Use replication and tunable consistency levels to balance consistency, availability, and performance Set up multiple data centers to enable failover, load balancing, and geographic distribution Add capacity to your cluster with zero downtime Take advantage of high availability features in the native driver Create data models that scale well and maximize availability Understand common anti-patterns so you can avoid them Keep your system working well even during failure scenarios In Detail Apache Cassandra is a massively scalable, peer-to-peer database designed for 100 percent uptime, with deployments in the tens of thousands of nodes, all supporting petabytes of data. This book offers a practical insight into building highly available, real-world applications using Apache Cassandra. The book starts with the fundamentals, helping you to understand how Apache Cassandra's architecture allows it to achieve 100 percent uptime when other systems struggle to do so. You'll get an excellent understanding of data distribution, replication, and Cassandra's highly tunable consistency model. Then we take an in-depth look at Cassandra's robust support for multiple data centers, and you'll see how to scale out a cluster. Next, the book explores the domain of application design, with chapters discussing the native driver and data modeling. Lastly, you'll find out how to steer clear of common anti-patterns and take advantage of Cassandra's ability to fail gracefully. Style and approach This practical guide will get you implementing Cassandra right from the design to creating highly available systems. Through a systematic, step-by-step approach, you will learn different aspects of building highly available Cassandra applications and all this with the help of easy-to-follow examples, tips, and tricks.

Download or read book Learning Apache Cassandra Second Edition written by Sandeep Yarabarla and published by . This book was released on 2017-03-31 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Build a scalable, fault-tolerant and highly available data layer for your applications using Apache CassandraAbout This Book* Install Cassandra and use it to set up multi-node clusters* Design rich schemas that capture the relationships between different data types* Master the advanced features available in Cassandra 3.x through a step-by-step tutorial and build a scalable, high performance database layerWho This Book Is ForIf you are a first-time user of Apache Cassandra who wants to learn the basic of it, as well as some not-so-basic features, this book is for you. It does not assume any prior experience in coding or any framework.What you will learn* Install Cassandra and create your first keyspace* Create tables with multiple clustering columns to organize related data* Use secondary indexes and materialized views to avoid denormalization of data* Effortlessly handle concurrent updates with collection columns* Ensure data integrity with lightweight transactions and logged batches* Understand eventual consistency and use the right consistency level for your situation* Understand data distribution with Cassandra and get to know ways to implement application-level optimizationsIn DetailCassandra is a distributed database that stands out thanks to its robust feature set and intuitive interface, while still providing the high availability and scalability of a distributed store. This book will introduce you to the rich features offered by Cassandra, and empower you to create and manage a highly performant, fault-tolerant database layer.The book starts by explaining the new features implemented in Cassandra 3.x, you'll see how to install Cassandra, and you'll understand Lightweight Transactions. Next you'll learn to create tables with composite partition keys, and get to know different methods to avoid denormalization of data. You will then proceed to create user-defined functions and data distribution in Cassandra. Finally, you will set up a multi node cluster and implement application-level optimization using a Java client.By the end of this book, you'll be fully equipped to build powerful, scalable Cassandra database layers for your applications.

Download or read book Mastering Distributed Tracing written by Yuri Shkuro and published by Packt Publishing Ltd. This book was released on 2019-02-28 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understand how to apply distributed tracing to microservices-based architectures Key FeaturesA thorough conceptual introduction to distributed tracingAn exploration of the most important open standards in the spaceA how-to guide for code instrumentation and operating a tracing infrastructureBook Description Mastering Distributed Tracing will equip you to operate and enhance your own tracing infrastructure. Through practical exercises and code examples, you will learn how end-to-end tracing can be used as a powerful application performance management and comprehension tool. The rise of Internet-scale companies, like Google and Amazon, ushered in a new era of distributed systems operating on thousands of nodes across multiple data centers. Microservices increased that complexity, often exponentially. It is harder to debug these systems, track down failures, detect bottlenecks, or even simply understand what is going on. Distributed tracing focuses on solving these problems for complex distributed systems. Today, tracing standards have developed and we have much faster systems, making instrumentation less intrusive and data more valuable. Yuri Shkuro, the creator of Jaeger, a popular open-source distributed tracing system, delivers end-to-end coverage of the field in Mastering Distributed Tracing. Review the history and theoretical foundations of tracing; solve the data gathering problem through code instrumentation, with open standards like OpenTracing, W3C Trace Context, and OpenCensus; and discuss the benefits and applications of a distributed tracing infrastructure for understanding, and profiling, complex systems. What you will learnHow to get started with using a distributed tracing systemHow to get the most value out of end-to-end tracingLearn about open standards in the spaceLearn about code instrumentation and operating a tracing infrastructureLearn where distributed tracing fits into microservices as a core functionWho this book is for Any developer interested in testing large systems will find this book very revealing and in places, surprising. Every microservice architect and developer should have an insight into distributed tracing, and the book will help them on their way. System administrators with some development skills will also benefit. No particular programming language skills are required, although an ability to read Java, while non-essential, will help with the core chapters.