Query hint generation

To improve performance, the Oracle driver generates hints in the native Oracle queries. When the resource ora_hint_no_hints is set, the driver will not generate any hint, except for queries with explicitly defined hints in the SQL query.

The hint generation tries to generate a database hint based on these origins:

• SQL query hints.
• Hints based on the ORDER BY clause.
• Hints based on the WHERE clause.

The hint origins are used in the order listed here, and the generation stops when a database hint is generated. Therefore, if a user generates a hint based on the ORDER BY clause, the hint generation no longer looks into the WHERE clause.