Thread: BUG #16067: Failed system call was semget
The following bug has been logged on the website: Bug reference: 16067 Logged by: chelsea lyu Email address: chelsealyu@gmail.com PostgreSQL version: 11.5 Operating system: MacOS Description: running bootstrap script ... 2019-10-19 23:25:15.095 JST [51410] FATAL: could not create semaphores: No space left on device 2019-10-19 23:25:15.095 JST [51410] DETAIL: Failed system call was semget(5432226, 17, 03600). this is the code what I input, and then the problem is out. MacBook-Pro:~ raye$ initdb /usr/local/var/postgres -E utf8 I also tried the code in the guide book of solving this question. RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmax kern.sysv.shmmax: 4194304 RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmin kern.sysv.shmmin: 1 RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmni kern.sysv.shmmni: 32 RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmseg kern.sysv.shmseg: 8 RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmall kern.sysv.shmall: 1024 but nothing happened. it still cannot work.
On Sat, Oct 19, 2019 at 02:54:45PM +0000, PG Bug reporting form wrote: >The following bug has been logged on the website: > >Bug reference: 16067 >Logged by: chelsea lyu >Email address: chelsealyu@gmail.com >PostgreSQL version: 11.5 >Operating system: MacOS >Description: > >running bootstrap script ... 2019-10-19 23:25:15.095 JST [51410] FATAL: >could not create semaphores: No space left on device >2019-10-19 23:25:15.095 JST [51410] DETAIL: Failed system call was >semget(5432226, 17, 03600). > >this is the code what I input, and then the problem is out. >MacBook-Pro:~ raye$ initdb /usr/local/var/postgres -E utf8 > > >I also tried the code in the guide book of solving this question. >RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmax >kern.sysv.shmmax: 4194304 >RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmin >kern.sysv.shmmin: 1 >RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmni >kern.sysv.shmmni: 32 >RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmseg >kern.sysv.shmseg: 8 >RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmall >kern.sysv.shmall: 1024 > >but nothing happened. >it still cannot work. > I think you need to tweak kernel.sem, not the options for sysv shared memory. Also, not a PostgreSQL bug, but an OS configuration issue ... regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
PG Bug reporting form <noreply@postgresql.org> writes:
> Operating system: MacOS
> running bootstrap script ... 2019-10-19 23:25:15.095 JST [51410] FATAL:
> could not create semaphores: No space left on device
> 2019-10-19 23:25:15.095 JST [51410] DETAIL: Failed system call was
> semget(5432226, 17, 03600).
That's a bit odd. macOS is known to have low default limits for
SysV shared memory, but not for semaphores. Which macOS version
are you running, exactly? What do you get from
sysctl -a | grep sysv.sem
? I get
kern.sysv.semmni: 87381
kern.sysv.semmns: 87381
kern.sysv.semmnu: 87381
kern.sysv.semmsl: 87381
kern.sysv.semume: 10
(and not only in Catalina, but very ancient mac versions)
Is it possible that something else is chewing up semaphores?
Looking at "sudo ipcs -s" output would reveal that.
> I also tried the code in the guide book of solving this question.
> RAYEdeMacBook-Pro:~ raye$ sysctl -w kern.sysv.shmmax
> kern.sysv.shmmax: 4194304
That is not about this problem.
regards, tom lane
On Sun, Oct 20, 2019 at 4:43 PM Tom Lane <tgl@sss.pgh.pa.us> wrote: > > PG Bug reporting form <noreply@postgresql.org> writes: > > Operating system: MacOS > > > running bootstrap script ... 2019-10-19 23:25:15.095 JST [51410] FATAL: > > could not create semaphores: No space left on device > > 2019-10-19 23:25:15.095 JST [51410] DETAIL: Failed system call was > > semget(5432226, 17, 03600). > > That's a bit odd. macOS is known to have low default limits for > SysV shared memory, but not for semaphores. Which macOS version > are you running, exactly? What do you get from > sysctl -a | grep sysv.sem > ? I get > > kern.sysv.semmni: 87381 > kern.sysv.semmns: 87381 > kern.sysv.semmnu: 87381 > kern.sysv.semmsl: 87381 > kern.sysv.semume: 10 > > (and not only in Catalina, but very ancient mac versions) > > Is it possible that something else is chewing up semaphores? > Looking at "sudo ipcs -s" output would reveal that. I have seen a Mac get into that state a couple of times after much uptime and much hacking and testing, and had to clean them up manually with ipcrm. Perhaps the occasional kill -9 (don't try this at home) or postmaster crash, with some bad luck I guess IpcSemaphoreCreate() could be fooled by a PID that has been recycled, and decide not to recycle the sema? I don't think it's anything to do with macOS really, just the fact that we don't use SysV flavoured semaphores elsewhere and even then most people don't do weird things to their PostgreSQL clusters like pgsql-hackers denizens...