File descriptors inherited by restore_command

Hackers,

While investigating "Too many open files" errors reported in our
parallel restore_command I noticed that the restore_command can inherit
quite a lot of fds from the recovery process. This limits the number of
fds available in the restore_command depending on the setting of system
nofile and Postgres max_files_per_process.

I was wondering if we should consider closing these fds before calling
restore_command? It seems like we could do this by forking first or by
setting FD_CLOEXEC using fcntl() or O_CLOEXEC on open() where available.

Thoughts on this? Is this something we want to change or should I just
recommend that users set nofile and max_files_per_process appropriately?

Regards,
--
-David
david(at)pgmasters(dot)net