Re: semaphore usage "port based"? - Mailing list pgsql-hackers

On Sun, 2 Apr 2006, Tom Lane wrote:

> "Marc G. Fournier" <scrappy@postgresql.org> writes:
>> On Sun, 2 Apr 2006, Tom Lane wrote:
>>> BTW, even before doing that, you should look at "ipcs -s" output to try
>>> to get a clue what's going on.  The EINVAL failures may be because the
>>> second postmaster to start deletes the semaphores created by the first
>>> one.  You could easily see this happening in before-and-after ipcs data
>>> if so.
>
>> You are right ...
>
> OK, could we see strace (or whatever BSD calls it) output for the second
> postmaster?  I'd like to see exactly what results it's getting for the
> kernel calls it makes during IpcSemaphoreCreate.

'k, dont' know what strace is ... we have ktrace and truss ... truss is 
what I usually use, and is:

DESCRIPTION     The truss utility traces the system calls called by the specified process     or program.  Output is to
thespecified output file, or standard error by     default.  It does this by stopping and restarting the process being
moni-    tored via procfs(5).
 

And shows output like:

# truss ls
ioctl(1,TIOCGETA,0x7fbff514)                     = 0 (0x0)
ioctl(1,TIOCGWINSZ,0x7fbff588)                   = 0 (0x0)
getuid()                                         = 0 (0x0)
readlink("/etc/malloc.conf",0x7fbff470,63)       ERR#2 'No such file or directory'
mmap(0x0,4096,0x3,0x1002,-1,0x0)                 = 671666176 (0x2808d000)
break(0x809b000)                                 = 0 (0x0)
break(0x809c000)                                 = 0 (0x0)
break(0x809d000)                                 = 0 (0x0)
break(0x809e000)                                 = 0 (0x0)
stat(".",0x7fbff470)                             = 0 (0x0)
open(".",0x0,00)                                 = 3 (0x3)
fchdir(0x3)                                      = 0 (0x0)
open(".",0x0,00)                                 = 4 (0x4)
stat(".",0x7fbff430)                             = 0 (0x0)
open(".",0x4,00)                                 = 5 (0x5)
fstat(5,0x7fbff430)                              = 0 (0x0)
fcntl(0x5,0x2,0x1)                               = 0 (0x0)
__sysctl(0x7fbff2e8,0x2,0x8098760,0x7fbff2e4,0x0,0x0) = 0 (0x0)
fstatfs(0x5,0x7fbff330)                          = 0 (0x0)
break(0x809f000)                                 = 0 (0x0)
getdirentries(0x5,0x809e000,0x1000,0x809a0b4)    = 512 (0x200)
getdirentries(0x5,0x809e000,0x1000,0x809a0b4)    = 0 (0x0)
lseek(5,0x0,0)                                   = 0 (0x0)
close(5)                                         = 0 (0x0)
fchdir(0x4)                                      = 0 (0x0)
close(4)                                         = 0 (0x0)
fstat(1,0x7fbff270)                              = 0 (0x0)
break(0x80a0000)                                 = 0 (0x0)
ioctl(1,TIOCGETA,0x7fbff2a4)                     = 0 (0x0)
.cshrc          .cvspass        .history        .login          .psql_history   .ssh
write(1,0x809f000,53)                            = 53 (0x35)
.cshrc~         .emacs.d        .klogin         .profile        .rnd            ktrace.out
write(1,0x809f000,53)                            = 53 (0x35)
exit(0x0)                                       process exit, rval = 0


ktrace is:

DESCRIPTION     The ktrace utility enables kernel trace logging for the specified pro-     cesses.  Kernel trace data
islogged to the file ktrace.out.  The kernel     operations that are traced include system calls, namei translations,
sig-    nal processing, and I/O.
 

And shows output like:
 86523 ls       RET   __sysctl 0 86523 ls       CALL  fstatfs(0x5,0x7fbff330) 86523 ls       RET   fstatfs 0 86523 ls
   CALL  break(0x809f000) 86523 ls       RET   break 0 86523 ls       CALL
getdirentries(0x5,0x809e000,0x1000,0x809a0b4)86523 ls       RET   getdirentries 512/0x200 86523 ls       CALL
getdirentries(0x5,0x809e000,0x1000,0x809a0b4)86523 ls       RET   getdirentries 0 86523 ls       CALL
lseek(0x5,0,0,0,0)


----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org           Yahoo!: yscrappy              ICQ: 7615664