postmaster process and multithreading - Mailing list pgsql-interfaces

 

I compiled postgres with threading enabled because I wanted

multithreading in the client process that I was writing. I don't

necessarily care if all server processes are multithreaded but

it does look like it affects the postmaster process in some way.

 

The reason I am asking is because sometimes the postmaster

will create a core dump and it will show two threads but the

backtrace on both threads does not show any helpful information.

I am wondering if I can disable multithreading in the postmaster/server

file compiles and by doing so make the gdb output a little more helpful.

 

I have include gdb backtraces. Any ideas are welcome.

BTW I am running postgres 8.2.5 and Freebsd 4.10.

 

Here is what I get:

# gdb postgres -c /cores/postgres-0-474dcec7
GNU gdb 4.18 (FreeBSD)
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.

Core was generated by `postgres'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /usr/lib/libcrypt.so.2...done.
Reading symbols from /usr/lib/libm.so.2...done.
Reading symbols from /usr/lib/libc_r.so.4...done.
Reading symbols from /usr/libexec/ld-elf.so.1...done.
#0  0x8837bc94 in thread_sigframe_add (thread=0x0, sig=0, has_args=0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c:1093
1093    /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c: No such file or directory.
(gdb) bt
#0  0x8837bc94 in thread_sigframe_add (thread=0x0, sig=0, has_args=0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c:1093

(gdb) info threads
  2 process 264745  _thread_kern_scheduler ()
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:602
* 1 process 133673  0x8837bc94 in thread_sigframe_add (thread=0x0, sig=0,
    has_args=0) at /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c:1093
(gdb) thread 2
[Switching to thread 2 (process 264745)]
#0  _thread_kern_scheduler ()
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:602
602     /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c: No such file or directory.
(gdb) bt
#0  _thread_kern_scheduler ()
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:602
#1  0x0 in ?? ()
(gdb) bt full
#0  _thread_kern_scheduler ()
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:602
        ts = {tv_sec = 102, tv_nsec = 799262000}
        tv = {tv_sec = 102, tv_usec = 799262}
        curthread = (struct pthread *) 0x8327000
        pthread = 0x883c5090
        pthread_h = 0x8327000
        current_tick = 0
        add_to_prioq = 1
#1  0x0 in ?? ()
No symbol table info available.
(gdb) thread 1
[Switching to thread 1 (process 133673)]
#0  0x8837bc94 in thread_sigframe_add (thread=0x0, sig=0, has_args=0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c:1093
1093    /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c: No such file or directory.
(gdb) bt full
#0  0x8837bc94 in thread_sigframe_add (thread=0x0, sig=0, has_args=0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_sig.c:1093
        has_args = -2009207968
        psf = (struct pthread_signal_frame *) 0x0
        stackp = 0
(gdb) l main
55      main.c: No such file or directory.
(gdb) l PostmasterMain
373     postmaster.c: No such file or directory.
(gdb) print IsPostmasterEnvironment
$1 = 1 '\001'
(gdb) print MyProcPid
$2 = 2601
(gdb) print IsUnderPostmaster
$3 = 0 '\000'

(gdb) print StartupPID
$4 = 0
(gdb) print BgWriterPID
$5 = 2652
(gdb) print PgStatPID
$6 = 2653
(gdb) quit

 

If I attach gdb to a health postmaster thread #1 bt still does not look correct:

 

0x8838094c in __sys_poll () from /usr/lib/libc_r.so.4
(gdb) info threads
  2 process 36551, thread 2  0x8837f1bb in _thread_kern_sched (ucp=0x0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:123
* 1 process 36551, thread 1  0x8838094c in __sys_poll () from /usr/lib/libc_r.so.4
(gdb) bt full
#0  0x8838094c in __sys_poll () from /usr/lib/libc_r.so.4
No symbol table info available.
#1  0x8837fe74 in thread_kern_poll (wait_reqd=1)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:829
        count = 0
        i = -2009313020
        found = -1077937916
        kern_pipe_added = 1
        nfds = 3
        timeout_ms = 60000
        pthread = (struct pthread *) 0x0
        ts = {tv_sec = 6593, tv_nsec = 729608000}
        tv = {tv_sec = 6593, tv_usec = 729608}
#2  0x8837f81e in _thread_kern_scheduler ()
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:504
        ts = {tv_sec = 6593, tv_nsec = 729608000}
        tv = {tv_sec = 6593, tv_usec = 729608}
        curthread = (struct pthread *) 0x883dc9a0
        pthread = 0x883c5090
        pthread_h = 0x0
        current_tick = 2285764128
        add_to_prioq = 0
#3  0x0 in ?? ()
No symbol table info available.
(gdb) thread 2
[Switching to thread 2 (process 36551, thread 2)]
#0  0x8837f1bb in _thread_kern_sched (ucp=0x0)
    at /usrbsd/src/lib/libc_r/uthread/uthread_kern.c:123
123     /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c: No such file or di
rectory.
(gdb) bt full
#0  0x8837f1bb in _thread_kern_sched (ucp=0x0)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:123
        curthread = (struct pthread *) 0x8327000
#1  0x8837f9f9 in _thread_kern_sched_state (state=PS_SELECT_WAIT,
    fname=0x883be360 "/usr/bsd/src/lib/libc_r/uthread/uthread_select.c",
    lineno=149) at /usr/bsd/src/lib/libc_r/uthread/uthread_kern.c:637
        state = PS_SELECT_WAIT
        fname = 0x883be360 "/usr/bsd/src/lib/libc_r/uthread/uthread_select
.c"
        curthread = (struct pthread *) 0xbfbff904

#2  0x8837c94f in _select (numfds=7, readfds=0xbfbff9d4, writefds=0x0,
    exceptfds=0x0, timeout=0xbfbff9c4)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_select.c:149
        timeout = (struct timeval *) 0xbfbff904
        curthread = (struct pthread *) 0x8327000
        ts = {tv_sec = 60, tv_nsec = 0}
        i = 4
        ret = 0
        f_wait = 1
        pfd_index = -1077937916
        got_events = -1077937900
        fd_count = 2
        data = {nfds = 2, fds = 0x8327c00}
#3  0x8837cb66 in select (numfds=7, readfds=0xbfbff9d4, writefds=0x0,
    exceptfds=0x0, timeout=0xbfbff9c4)
    at /usr/bsd/src/lib/libc_r/uthread/uthread_select.c:271
        exceptfds = (fd_set *) 0x0
        timeout = (struct timeval *) 0xbfbff9c4
        ret = -1077937724
#4  0x817c80b in ServerLoop () at postmaster.c:1162
        port = (Port *) 0xbfbff9c4
        rmask = {fds_bits = {96, 0 <repeats 31 times>}}
        timeout = {tv_sec = 60, tv_usec = 0}
        selres = -1077937724
        i = -1077937452
        readmask = {fds_bits = {96, 0 <repeats 31 times>}}
        nSockets = 7
        now = -1077937724
        last_touch_time = 1196288034
        earlier = {tv_sec = 1196288034, tv_usec = 365978}
        later = {tv_sec = -2009303956, tv_usec = 2}
#5  0x817c42a in PostmasterMain (argc=11, argv=0xbfbffbac) at postmaster.c:966
        opt = 137671169
        status = 209
        userDoption = 0x834b200 "\220\002"
        i = 60000
#6  0x8142974 in main (argc=11, argv=0xbfbffbac) at main.c:188
        argv = (char **) 0xbfbffbac
(gdb)