As you know, Solr creates an inverted index of the data you ingest, so the process of adding data to Solr is called indexing. Primarily what you do in Solr is index and search, and for data to be searchable, it must be indexed.
In Chapter 2, you indexed sample documents by using the Solr admin console. In this chapter, you will learn about the indexing process in depth and width. By depth, I mean getting a detailed understanding of the process. I refer to width in terms of the variety of decisions you need to make before indexing a document, such as the document format, indexing tool, the frequency of indexing, document ...