Re: cuckoo is hung during regression test

"Jim C. Nasby" <jim@nasby.net> writes:
> The postmaster is stuck in the following loop, according to
> ktrace/kdump:

>   2023 postgres CALL  select(0x8,0xbfffe194,0,0,0xbfffe16c)
>   2023 postgres RET   select 1
>   2023 postgres CALL  sigprocmask(0x3,0x2f0d38,0)
>   2023 postgres RET   sigprocmask 0
>   2023 postgres CALL  accept(0x7,0x200148c,0x200150c)
>   2023 postgres RET   accept -1 errno 24 Too many open files
>   2023 postgres CALL  write(0x2,0x2003928,0x3b)
>   2023 postgres GIO   fd 2 wrote 59 bytes
>        "LOG:  could not accept new connection: Too many open files
>        "
>   2023 postgres RET   write 59/0x3b
>   2023 postgres CALL  close(0xffffffff)
>   2023 postgres RET   close -1 errno 9 Bad file descriptor
>   2023 postgres CALL  sigprocmask(0x3,0x2e6400,0)
>   2023 postgres RET   sigprocmask 0
>   2023 postgres CALL  select(0x8,0xbfffe194,0,0,0xbfffe16c)
>   2023 postgres RET   select 1

Interesting.  So accept() fails because it can't allocate an FD, which
means that the select condition isn't cleared, so we keep retrying
forever.  I don't see what else we could do though.  Having the
postmaster abort on what might well be a transient condition doesn't
sound like a hot idea.  We could possibly sleep() a bit before retrying,
just to not suck 100% CPU, but that doesn't really *fix* anything ...

I've been meaning to bug you about increasing cuckoo's FD limit anyway;
it keeps failing in the regression tests.

> ulimit is set to 1224 open files, though I seem to keep bumping into that
> (anyone know what the system-level limit is, or how to change it?)

On my OS X machine, "ulimit -n unlimited" seems to set the limit to
10240 (or so a subsequent ulimit -a reports).  But you could probably
fix it using the buildfarm parameter that cuts the number of concurrent
regression test runs.
        regards, tom lane