Using the hint table has been pretty painful, in my experience. Two main difficulties I’ve seen: 1. The hint patterns are whitespace-sensitive. Accidentally put a tab instead of a couple of spaces, and you get a silent match failure. 2. There are different ways to encode query parameters - `?` for literals in the query text, `$n` for query parameters. Psql / pgcli don’t support parameterized queries so you can’t use them to iterate on your hints.

Still super useful when you have no other options though.