In this post, we’ll walk through how lazy materialization works and how it fits into ClickHouse’s broader I/O optimization stack. To give a complete picture, we’ll also briefly demonstrate the other key building blocks of I/O efficiency in ClickHouse, highlighting not just what lazy materialization does, but how it differs from and complements the techniques already in place.` This sentence provides an objective summary of the text, covering the main topic of the post (lazy materialization) and its relationship with other optimization techniques in ClickHouse. It highlights that the post aims to provide a complete understanding of lazy materialization by briefly introducing other key building blocks of I/O efficiency in ClickHouse.