This is due to the fact that docker by default restricts shared memory size to 64MB which makes pg10 run afoul of this limitation when doing a number of scatter/gather jobs in parallel:
Outside the container:
supermathie@host: ~ $ df -h /dev/shm
Filesystem Size Used Avail Use% Mounted on
none 63G 1.2M 63G 1% /run/shm
Inside the container:
supermathie@host: ~ $ docker exec -it postgres-master df -h /dev/shm
Filesystem Size Used Avail Use% Mounted on
shm 64M 8.0K 64M 1% /dev/shm
You should raise the limit when launching the postgres container by including the --shm-size=1g parameter.
We’ll look at fixing this in the launcher.
(or as the link suggests, disable parallelism in pg10 with max_parallel_workers_per_gather = 0)