When I set max_parallel_workers_per_gather=0, the select statement can execute successfully.
The problem has been solved.
Thank you all very much.
Alan
At 2019-03-14 22:29:24, "Adrian Klaver" <adrian.klaver@xxxxxxxxxxx> wrote: >On 3/13/19 10:54 PM, fuzk wrote: >> Dear Adrian, >> >> My setting is as following. >> >> max_parallel_workers_per_gather=32 > >Not sure if it is possible without affecting other operations, but you >could set the above to 0 to temporarily disable parallel queries and see >if that eliminates the error. > >Also see: > >https://trac.osgeo.org/postgis/ticket/4129 > >> >> I am looking forward to hearing from you. >> >> Many thanks >> Alan. >> >> >> >> >> >> >> >> At 2019-03-13 22:31:11, "Adrian Klaver" <adrian.klaver@xxxxxxxxxxx> wrote: >>>On 3/12/19 7:54 PM, fuzk wrote: >>>> Dear Sir/Madam >>>> >>>> I got an error when I execute the following select sentence. >>>> Would you please solve the problem for me? >>> >>>What version of Postgres? >>> >>>> Thank you . >>>> >>>> Alan Fu. >>>> >>>> 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 guessing ST_length is not parallel safe. >>> >>>What is your setting for?: >>> >>>max_parallel_workers_per_gather >>> >>>> >>>> >>> >>> >>>-- >>>Adrian Klaver >>>adrian.klaver@xxxxxxxxxxx >> >> >> > > >-- >Adrian Klaver >adrian.klaver@xxxxxxxxxxx
