On Thu, Mar 14, 2019 at 4:59 PM Paul Ramsey <pramsey@xxxxxxxxxxxxxxxxx> wrote: > > On Thu, Mar 14, 2019 at 8:43 AM Julien Rouhaud <rjuju123@xxxxxxxxx> wrote: > > > > On Thu, Mar 14, 2019 at 3:25 PM Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote: > > > > > > On 3/14/19 6:14 AM, Julien Rouhaud wrote: > > > > On Thu, Mar 14, 2019 at 1:20 PM fuzk <fuzk80_76@xxxxxxx> wrote: > > > >> > > > >> Dear Adrian, > > > >> > > > >> My setting is as following. > > > >> > > > >> max_parallel_workers_per_gather=32 > > > >> > > > >> I am looking forward to hearing from you. > > > > > > > > What version of postgres and what version of postgis are you using ? > > > > > > > >> At 2019-03-13 22:31:11, "Adrian Klaver" <adrian.klaver@xxxxxxxxxxx> wrote: > > > >>> On 3/12/19 7:54 PM, fuzk wrote: > > > >>>> postgres=# \set VERBOSITY verbose > > > >>>> postgres=# SELECT > > > >>>> round(cast(coalesce(sum(ST_length(geography(geometry)))/1000,0) as > > > >>>> NUMERIC),4)||'KM' field_value from had_link; > > > >>>> > > > >>>> ERROR: XX000: cannot update SecondarySnapshot during a parallel operation > > > >>>> CONTEXT: SQL statement "SELECT proj4text FROM public.spatial_ref_sys > > > >>>> WHERE srid = 4326 LIMIT 1" > > > >>>> parallel worker > > > >>>> LOCATION: GetLatestSnapshot, snapmgr.c:387 > > > > > > > > I'm not familiar at all with geography, but if I read the code > > > > correctly, ST_Length / geography_length will call > > > > spheroid_init_from_srid(), which eventuallly calls GetProj4StringSPI() > > > > that run a query using SPI. I'm not sure why exactly > > > > GetLatestSnapshot() is called here, or if SPI is really allowed in > > > > parallel workers, but that's the problem here apparently. I'm adding > > > > Paul as he'll probably have a way better answer than me. > > > > > > > > > > https://trac.osgeo.org/postgis/ticket/4129 > > > "Cannot update SecondarySnapshot during a parallel operation" > > > > Ah, I didn't look there indeed, thanks! So postgis people are already > > aware, that's a good news. > > Aware but unable to replicate, so nothing is happening on that front. > If you can create a set of data, SQL statements and configuration that > replicates, that would aid immensely. I also tried to reproduce on latest postgis 2.4 / pg11 with anything even slightly related to what could call GetLatestSnapshot() with force_parallel_mode enabled and parallel_leader_participation disabled (also postgis installcheck), and I couldn't hit this problem (while I'm sure that the underlying query was run). I start to think that this may be due to a third-party module loaded that could call GetLatestSnapshot(), otherwise I have no explanation.
