Introduction

This article will explain how the data is organized in InnoDB storage engine. First we will look at the various files that are created by InnoDB, then we look at the logical data organization like tablespaces, pages, segments and extents. We will explore each of them in some detail and discuss about their relationship with each other. At the end of this article, the reader will have a high level view of the data layout within the InnoDB storage engine.

The Files

MySQL will store all data within the data directory. The data directory can be specified using the command line option –data-dir or in the configuration file as datadir. Refer to the Server Command Options for complete details.

By default, when InnoDB is initialized, it creates 3 important files in the data directory – ibdata1, ib_logfile0 and …