This paragraph summarizes the key points of the text: YugabyteDB's YSQL API uses the pg_hint_plan extension in PostgreSQL to tweak query execution plans, which can lead to sub-optimal performance at times. To optimize queries, developers can use "hinting" phrases as comments to influence the planner's execution plan. These phrases can be inserted into a table called "hints" to capture query-related suggestions that the planner should leverage. The "hints" table preserves special characters and whitespace, making it useful for optimizing queries without modifying application code. Developers can also use this feature in their client applications written in languages like Java, adjusting hint phrases based on usage patterns such as Statement API with static constants, PreparedStatement API with bind parameters, or PreparedStatement API with both bind and static constants. By leveraging pg_hint_plan, developers can optimize YSQL query performance without modifying application code.