Parker Ace的专栏

Welcome to the world of ElasticSearch and to the Mastering ElasticSearch book. While reading the book you'll be taken through different topics, all connected to ElasticSearch. We will start with the introduction to Apache Lucene and ElasticSearch, because even if you are familiar with it, it is crucial to have the background in order to fully understand what is going on when you form a cluster, send a document for indexing, or make a query. You will learn how Apache Lucene scoring works, how to influence it, and how to tell ElasticSearch to choose different scoring algorithms. The book will show you what query rewriting is and why it happens. Apart from that, you'll see how to change your queries to leverage ElasticSearch caching capabilities and make maximum use of it. After that we will focus on index control. We will learn the way to change how index fields are written, by using different posting formats. We will discuss segments merging, why it is important, and how to adjust it when there is a need. We'll take a deeper look at shard allocation mechanism and routing, and finally we'll learn what to do when data and query number grows. The book can't omit garbage collector description—how it works and where to start and when you need to tune its behavior. In addition to that, it covers functionalities that allow us to troubleshoot ElasticSearch, such as describing how segments merging works, how to see what ElasticSearch does beneath its high-level interface, and how to limit the I/O operations. But the book doesn't only pay attention to low-level aspects of ElasticSearch; it includes user search experience improvements tips, such as dealing with spelling mistakes, highly effective autocomplete feature, and a tutorial on how you can deal with query related improvements. In addition to this, the book you are holding will guide you through ElasticSearch Java API, showing how to use it, not only when it comes to CRUD operations but also when it comes to cluster and indices maintenance and manipulation. Finally, we will take a deep look at ElasticSearch extensions by developing a custom river plugin for data indexing and a custom analysis plugin for data analysis during query and index time.