MySQL Force Index Drawbacks

The use of forced indexing may lead to several potential issues:

1. Performance degradation: Forcing an index may not be the optimal query path, potentially leading to a decrease in query performance. The database optimizer typically selects the most suitable index based on query conditions and index statistics, but forcing an index bypasses this optimization process and may choose a less efficient index.
2. Difficulty in maintenance: Mandatory indexing may pose challenges in maintaining the database. When there are changes in the database table structure, mandatory indexes need to be manually adjusted to fit the new table structure, which could result in errors or require a significant amount of manual work.
3. Index redundancy: Forcing an index may introduce index redundancy. If there is already an index applicable for the query, but a forced index is used, then a redundant index will be created in the database, taking up additional storage space.
4. Poor portability: enforcing indexes may result in code that is not portable across different databases. Different database management systems may have different syntax and behaviors for enforced indexes, so code may need to be modified when switching databases.

Therefore, try to avoid unnecessary forced indexes and instead allow the database optimizer to choose the most appropriate index based on the query conditions and index statistics. Forced indexes should only be considered in specific cases where query performance cannot be optimized in any other way.