On Wed, May 17, 2017 at 1:30 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Sat, May 13, 2017 at 7:27 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: >> On Fri, May 12, 2017 at 9:14 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> Robert Haas <robertmh...@gmail.com> writes: >>>> On Wed, May 10, 2017 at 8:39 PM, Masahiko Sawada <sawada.m...@gmail.com> >>>> wrote: >>>>> ... I'd like to propose to change relation >>>>> extension lock management so that it works using LWLock instead. >>> >>>> That's not a good idea because it'll make the code that executes while >>>> holding that lock noninterruptible. >>> >>> Is that really a problem? We typically only hold it over one kernel call, >>> which ought to be noninterruptible anyway. >> >> During parallel bulk load operations, I think we hold it over multiple >> kernel calls. > > We do. Also, RelationGetNumberOfBlocks() is not necessarily only one > kernel call, no? Nor is vm_extend.
Yeah, these functions could call more than one kernel calls while holding extension lock. > Also, it's not just the backend doing the filesystem operation that's > non-interruptible, but also any waiters, right? > > Maybe this isn't a big problem, but it does seem to be that it would > be better to avoid it if we can. > I agree to change it to be interruptible for more safety. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers