Evaluate ownership membership once per authorization statement

When row authorization performs nested privileged ownership lookups, a historical read can become expensive even though each lookup uses an index. Evaluate ownership membership once per statement and use non-null primary-key membership sets where the protected population is small. Preserve caller identity, function ownership, search paths, source ownership, nullable references, and parent-link rules; test the deployed role against the same baseline. Membership sets grow with retained history, so this approach still needs measurement as that history grows. Applies when: Indexed per-row authorization causes historical reads to time out. Keywords: authorization row security ownership lookup historical query membership performance