Can incorrect use of indexes reduce database performance?

Yes, improper use of indexes can reduce database efficiency. While indexes speed up data searches, their excessive or inappropriate creation leads to:

• Increased time for insert, update, and delete operations, as indexes need to be maintained.
• Additional disk space usage.
• Possible degradation of query performance if the index does not match the query type or is used inefficiently.

For example, creating an index on a column with high cardinality (many unique values) is usually beneficial, whereas an index on a column with few unique values (e.g., a boolean column) may not improve performance and could even slow down operations.

Therefore, it is important to analyze queries and create indexes purposefully, using profiling and query execution plans.