Don't be fooled with the title! This is not just another article. 

"Data access methods used in Firebird" is a foundation document (88 pages!) for anyone serious about Firebird queries' performance. Just like important books that change how we think about technology, this article will change how you work with Firebird queries.

Created by author of Firebird documentation Denis Simonov and Firebird engine developer Dmitry Yemanov, this article explains complex concepts of Firebird optimization in clear language, with numerous examples and visual execution plans.

This document provides an unprecedented look at Firebird's query processing engine, covering:

• Primary data access methods - How Firebird reads tables, uses indexes, and processes data
• Filtering techniques - The various ways Firebird filters data streams
• Joining algorithms - Detailed explanations of Nested Loop, Hash, and Merge joins
• Advanced optimization strategies - How Firebird decides the most efficient execution plan

Who Should Read This

• Firebird Database Administrators
• Advanced SQL developers
• Anyone who wants to make their Firebird databases run better

This knowledge is so important that we will use it as the basis for our Advanced Certification Exam for Firebird SQL developers. 

Read article here  (also available as PDF version).