Two tests:
1. pcntl_fork concurrent-INSERT test (skipped on Windows/no pcntl) —
demonstrates chain branch when 5 workers insert into the same partition
simultaneously; passes after advisory-lock migration.
2. pg_locks advisory lock presence test (Windows-compatible) —
verifies that pg_advisory_xact_lock is actually held in pg_locks
during an INSERT transaction, proving the migration works.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>