What are indexes and what are their disadvantages?

Indexes in databases are needed to speed up search and data retrieval. They allow quick finding of records without scanning the entire table, using data structures (for example, B-trees).

Advantages of indexes:

• Significantly accelerate SELECT operations with conditions on indexed fields.
• Help with sorting and joins.

Disadvantages:

• Take up additional disk space.
• Slow down insert, update, and delete operations, as the index needs to be updated.
• Excessive indexes can degrade overall performance.

In Go, indexes usually refer to the databases that the application works with, not to the slices or arrays of the language.