ERROR: could not map dynamic shared memory segment

Hi ,

I am getting  ERROR:  could not map dynamic shared memory segment in the 
log file

- Please refer this scenario-

in V11/V10 latest sources

  set parallel_setup_cost=0;
  set parallel_tuple_cost=0;
  set max_parallel_workers_per_gather=4;
  create table r(n int);
insert into r values (generate_series(1,1000000));
insert into r values (generate_series(1000000,2000000));
analyze r;

postgres=# select * from r where n < (select n from r where n<=10000 
limit 6644);
ERROR:  more than one row returned by a subquery used as an expression

in the log file -

2018-02-07 10:28:27.615 GMT [20569] ERROR:  more than one row returned 
by a subquery used as an expression
2018-02-07 10:28:27.615 GMT [20569] STATEMENT:  select * from r where n 
< (select n from r where n<=10000 limit 6644);
2018-02-07 10:28:27.616 GMT [20586] ERROR:  could not map dynamic shared 
memory segment
2018-02-07 10:28:27.616 GMT [20587] ERROR:  could not map dynamic shared 
memory segment
2018-02-07 10:28:27.617 GMT [20559] LOG:  background worker "parallel 
worker" (PID 20586) exited with exit code 1
2018-02-07 10:28:27.617 GMT [20559] LOG:  background worker "parallel 
worker" (PID 20587) exited with exit code 1

Is this something already reported ?

-- 
regards,tushar
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