While on the road in Iowa visiting covered bridges I met up with an amazing individual named Brent. Brent, is with a small organization named: Darpa.
They are using PostgreSQL + RLS + XPATH but unfortunately the performance has been less than what those who use PostgreSQL on a daily basis would expect. Specifically when using RLS + XPATH, the optimizer does not prefilter and will scan every row. This has taken their previous queries on another database from sub second, to 25+ seconds on PostgreSQL.
Unfortunately, we were at a covered bridge park (see attached) and weren't able to get deeper into the issue. That said, I did tell him that I would report the issue. Maybe there is traction, maybe there isn't to get this issue fixed.
