Why does VACUUM in PostgreSQL not repair indexes?

The article on 'boringsql.com' discusses the topic of the VACUUM command in the PostgreSQL database system. VACUUM is often touted as a tool for reclaiming space after data deletion, but the author points out that this is not all one needs to know about this command. Several key issues related to VACUUM's operation are highlighted in the article, including its impact on performance and disk space management. It is important to understand that VACUUM does not always function in the expected manner, and its effects are not instantaneous. Furthermore, the author presents alternatives to this operation and provides tips on their application, which can be useful for anyone managing database performance. Additionally, the article is aimed at individuals who wish to better understand how the PostgreSQL system operates and what options we have for optimizing its performance in the context of data management.