What signs indicate the need to create an index in a database?

Signs indicating the need to create an index in a database:

• Frequent queries with filtering on specific columns (WHERE, JOIN, ORDER BY) that are slow.
• The table contains a large number of records, and searching it takes a significant amount of time.
• A column is used for sorting or grouping data.
• There is a need to speed up search operations on unique or frequently used values.

An index helps speed up data retrieval but increases insert and update times, so indexes should be created consciously, based on actual queries and load.