Hi, On 2020-01-08 17:31:06 -0500, Tom Lane wrote: > (1) d20703805's test will clearly fall over if there are more than six > FDs open in the postmaster when set_max_safe_fds is called, because it > sets max_files_per_process = 26 while set_max_safe_fds requires at > least 20 usable FDs to be available.
> (4) NetBSD 7.0's cron leaves three extra open FDs in processes that > it spawns. I have not looked into why, but I have experimentally > observed this. For example, lsof on a "sleep" launched from cron > shows > > COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME > sleep 7824 tgl cwd VDIR 0,0 512 795201 /home/tgl > sleep 7824 tgl txt VREG 0,0 10431 1613152 /bin/sleep > sleep 7824 tgl txt VREG 0,0 1616564 22726 > /lib/libc.so.12.193.1 > sleep 7824 tgl txt VREG 0,0 55295 22747 > /lib/libgcc_s.so.1.0 > sleep 7824 tgl txt VREG 0,0 187183 22762 > /lib/libm.so.0.11 > sleep 7824 tgl txt VREG 0,0 92195 1499524 > /libexec/ld.elf_so > sleep 7824 tgl 0r PIPE 0xfffffe803131eb58 16384 > sleep 7824 tgl 1w PIPE 0xfffffe8007ec4a30 0 > ->0xfffffe800cc0d2c0 > sleep 7824 tgl 2w PIPE 0xfffffe8007ec4a30 0 > ->0xfffffe800cc0d2c0 > sleep 7824 tgl 7u unknown > file system type: 0 > sleep 7824 tgl 8u unknown > file system type: 0 > sleep 7824 tgl 9w PIPE 0xfffffe80036c4dc0 0 > > while of course "sleep" launched by hand has only 0/1/2 open. Is it worth having the test close superflous FDs? It'd not be hard to do so via brute force (or even going through /proc/self/fd). Greetings, Andres Freund
