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

On Thu, Mar 14, 2019 at 8:43 AM Julien Rouhaud <rjuju123@gmail.com> wrote:
>
> On Thu, Mar 14, 2019 at 3:25 PM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
> >
> > On 3/14/19 6:14 AM, Julien Rouhaud wrote:
> > > On Thu, Mar 14, 2019 at 1:20 PM fuzk <fuzk80_76@163.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.klaver@aklaver.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.

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.