Which of the following is a disadvantage of database indexing?

The correct choice highlights a key aspect of database indexing: while indexes can enhance the speed and efficiency of retrieving data, they also necessitate additional storage space. Each index created on a database table consumes extra disk space because it involves maintaining a separate data structure that organizes the indexed data for quicker access. This extra storage can become significant, particularly in databases with large volumes of data or numerous indexes.

Moreover, while indexes can greatly improve read performance, they may also introduce trade-offs, particularly regarding write operations such as inserts, updates, or deletes, as the indexes must be kept in sync with the actual data. This requires additional processing, which can negate some of the performance gains during data modifications. Therefore, understanding that indexes require additional storage space is crucial when designing and managing database systems.