On 2/28/17 10:22 PM, Robert Haas wrote: > On Tue, Feb 28, 2017 at 6:22 AM, David Steele <da...@pgmasters.net> wrote: >>>> I'm not sure that's the case. It seems like it should lock just as >>>> multiple backends would now. One process would succeed and the others >>>> would error. Maybe I'm missing something? >>> >>> Hm, any errors happening in the workers would be reported to the >>> leader, meaning that even if one worker succeeded to run >>> pg_start_backup() it would be reported as an error at the end to the >>> client, no? By marking the exclusive function restricted we get sure >>> that it is just the leader that fails or succeeds. >> >> Good point, and it strengthens the argument beyond, "it just seems right." > > I think the argument should be based on whether or not the function > depends on backend-private state that will not be synchronized. > That's the definition of what makes something parallel-restricted or > not.
Absolutely. Yesterday was a long day so I may have (perhaps) become a bit flippant. > It looks like pg_start_backup() and pg_stop_backup() depend on the > backend-private global variable nonexclusive_backup_running, so they > should be parallel-restricted. Agreed. -- -David da...@pgmasters.net -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
