docker

const DefaultShmSize = "1g"

DefaultShmSize is the /dev/shm given to a testing image that does not set its own. Docker's default is 64 MB, which Postgres parallel queries exhaust: every parallel worker opens a segment in /dev/shm, and a worker that cannot resize its segment fails the query with `SQLSTATE 53100`. A killed worker also leaves its segment behind, so a container that keeps running slowly fills its 64 MB and every later query fails while it does.