Jan Wieck <j...@wi3ck.info> writes: > So let's focus on the actual problem of running out of XIDs and memory > while doing the upgrade involving millions of small large objects.
Right. So as far as --single-transaction vs. --create goes, that's mostly a definitional problem. As long as the contents of a DB are restored in one transaction, it's not gonna matter if we eat one or two more XIDs while creating the DB itself. So we could either relax pg_restore's complaint, or invent a different switch that's named to acknowledge that it's not really only one transaction. That still leaves us with the lots-o-locks problem. However, once we've crossed the Rubicon of "it's not really only one transaction", you could imagine that the switch is "--fewer-transactions", and the idea is for pg_restore to commit after every (say) 100000 operations. That would both bound its lock requirements and greatly cut its XID consumption. The work you described sounded like it could fit into that paradigm, with the additional ability to run some parallel restore tasks that are each consuming a bounded number of locks. regards, tom lane