Justin Pryzby <pry...@telsasoft.com> writes: > I hit this issue intermittently (roughly half the time) while working with a > patch David submitted, and finally found a recipe to reproduce it on an > unpatched v12 instance.
> I was surprised to see pg_restore -j2 is restoring ACLs in pre-data in > parallel. It's not pre-data. But it's true that pg_restore figures it can restore ACLs in parallel during the ACL-restoring pass, on the theory that pg_dump will not emit two different ACL entries for the same object, so that we can do all the catalog updates in parallel without conflicts. This works about 99% of the time, in fact. It falls down in the --clean case if we have to revoke existing table permissions, because in that case the REVOKE at table level is required to clear the table's per-column ACLs as well, so that that ACL entry involves touching the same catalog rows that the per-column ACLs want to touch. I think the right fix is to give the per-column ACL entries dependencies on the per-table ACL, if there is one. This will not fix the problem for the case of restoring from an existing pg_dump archive that lacks such dependency links --- but given the lack of field complaints, I'm okay with that. This looks straightforward, if somewhat tedious because we'll have to change the API of pg_dump's dumpACL() function, which is called by a lot of places. Barring objections, I'll go do that. regards, tom lane