Inline hints are a simple way to directly influence the optimizer. But the fact that hints must be added to the statement text makes them difficult to use, especially when it's not possible to modify the application sending the statement.

This issue is about building a way to inject hints without changing the statements being hinted. A rough idea of the capability is something like:

SELECT crdb_internal.inject_hints(
  'SELECT name, age FROM cat WHERE breed = _ ORDER BY age DESC LIMIT _',
  'SELECT name, age FROM cat@cat_age_idx WHERE breed = _ ORDER BY age DESC LIMIT _'
);

Which will force the following query to use index cat_age_idx:

SELECT name, age
FROM cat
WHERE breed = 'shorthair'
ORDER BY age DESC
LIMIT 1;

Jira issue: CRDB-54520