Hi, On 2019-10-09 12:29:18 -0400, Robert Haas wrote: > I would say rather that if fork() is failing on your system, you have > a not very stable system.
I don't think that's really true, fwiw. It's often a good idea to turn on strict memory overcommit accounting, and with that set, it's actually fairly common to see fork() fail with ENOMEM, even if there's practically a reasonable amount of resources. Especially with larger shared buffers and without huge pages, the amount of memory needed for a postmaster child in the worst case is not insubstantial. > The fact that parallel query is going to fail is sad, but not as sad > as the fact that connecting to the database is also going to fail, and > that logging into the system to try to fix the problem may well fail > as well. Well, but parallel query also has to the potential to much more quickly lead to a lot of new backends being started than you'd get new connections on an analytics DB. > Code that tries to make parallel query cope with this situation > without an error wouldn't often be tested, so it might be buggy, and > it wouldn't necessarily be a benefit if it did work. I expect many > people would rather have the query fail and free up slots in the > system process table than consume precisely all of them and then try > to execute the query at a slower-than-expected rate. I concede that you have a point here. Greetings, Andres Freund
