ORACLE RAC－－在RAC節點上測試產生並調試core文件

ORACLE RAC－－在Linux下測試產生並調試core文件

1.查看伺服器內核版本：

[oracle@rac1 ~]$ uname -a
Linux rac1 2.6.18-164.el5 #1 SMP Thu Sep 3 03:33:56 EDT 2009 i686 i686 i386 GNU/Linux

再看看默認的一些參數,注意core file size是個0,程序出錯時不會產生core文件了.

[oracle@rac1 ~]$ ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 16384
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 4096
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 2047
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

2. 寫個簡單的程序,看看core文件是不是會被產生.

[oracle@rac1 ~]$ cat test.c

#include
#include

static void sub(void);
int main(void)
{
sub();
return 0;
}

static void sub(void)
{
int *p = NULL;
/* derefernce a null pointer, expect core dump. */
printf("%d", *p);
}

[oracle@rac1 ~]$ gcc -o test -g test.c //加上-g參數,便於使用gdb調試器
[oracle@rac1 ~]$ time ./test
Segmentation fault

real 0m0.004s
user 0m0.000s
sys 0m0.003s

[oracle@rac1 CR_TEST]$ ls -l core.*
ls: core.*: No such file or directory

沒有找到core文件,我們改改ulimit的設置,讓它產生.1024是隨便取的,要是core文件大於1024個塊,就產生不出來了.

[oracle@rac1 ~]$ ulimit -c 1024

[oracle@rac1 CR_TEST]$ ulimit -a
core file size (blocks, -c) 1024
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 16384
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 4096
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 2047
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

[oracle@rac1 CR_TEST]$ ./test
Segmentation fault (core dumped)
[oracle@rac1 CR_TEST]$ ls -l core.*
-rw------- 1 oracle oinstall 139264 Sep 27 13:35 core.29664

由上述的輸出信息,可以看到多了個(core dumped).確實產生了一個core文件,29664是該進程的PID.我們用GDB來看看這個core.

3.使用gdb命令調試：

[oracle@rac1 CR_TEST]$ gdb --core=core.29664
GNU gdb Fedora (6.8-37.el5)
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3 : GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu".
(no debugging symbols found)
Core was generated by `./test'.
Program terminated with signal 11, Segmentation fault.
[New process 29664]
#0 0x080483b8 in ?? ()
(gdb) bt

#0 0x080483b8 in ?? ()
#1 0x00ab9ff4 in ?? ()
#2 0x00ab8204 in ?? ()
#3 0xbf8d6198 in ?? ()
#4 0x080483f9 in ?? ()
#5 0x009a4e25 in ?? ()
#6 0x00000000 in ?? ()

此時使用bt看不到backtrace,也就是調用堆棧,原來GDB還不知道符號信息在哪裡.需要指定文件位置：

(gdb) file ./test
Reading symbols from /home/oracle/CR_TEST/test...done.
(gdb) bt
#0 0x080483b8 in sub () at test.c:15
#1 0x0804839a in main () at test.c:7

此時backtrace出來了.

(gdb) l 12
7 sub();
8 return 0;
9 }
10
11 static void sub(void)
12 {
13 int *p = NULL;
14 /* derefernce a null pointer, expect core dump. */
15 printf("%d", *p);
16 }

以上測試過程,即為在RAC節點上測試產生並調試core文件的全過程.

Tags: linux system 系統