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. 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. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers