We still have a little work to do on dependencies in parallel
pg_restore. The current test compares the candidate's locking
dependencies with those of the running jobs, and allows the candidate is
there isn't a match. That's not a broad enough test. The candidate will
block if there's a currently running CREATE INDEX command on the table,
for example, even though that doesn't require an exclusive lock. That's
not catastrophic, in that the restore doesn't fail, but it's fairly bad
because it reduces the achievable parallelism. Josh Berkus observed this
during testing on a very large restore.
cheers
andrew
