Re: ERROR: XX000: cannot update SecondarySnapshot during a parallel operation

On Thu, Mar 14, 2019 at 3:25 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> wrote:
>
> On 3/14/19 6:14 AM, Julien Rouhaud wrote:
> > On Thu, Mar 14, 2019 at 1:20 PM fuzk <fuzk80_76(at)163(dot)com> 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(dot)klaver(at)aklaver(dot)com> 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.