gdb调试之--readbyothersession等待事件的重现 - 数据库编程

from /lib64/libnsl.so.1...done. Loaded symbols for /lib64/libnsl.so.1 Reading symbols from /lib64/libc.so.6...done. Loaded symbols for /lib64/libc.so.6 Reading symbols from /lib64/ld-linux-x86-64.so.2...done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /usr/lib64/libnuma.so.1...done. Loaded symbols for /usr/lib64/libnuma.so.1 Reading symbols from /lib64/libnss_files.so.2...done. Loaded symbols for /lib64/libnss_files.so.2 Reading symbols from /u01/app/oracle/product/11.2.0/lib/libnque11.so...done. Loaded symbols for /u01/app/oracle/product/11.2.0/lib/libnque11.so 0x0000003f0d40d290 in __read_nocancel () from /lib64/libpthread.so.0 (gdb)

4、在会话1，执行select语句，此时select被阻塞

gyj@OCM> select * from gyj_test where id=1;

5、在gdb设断点，用等待事件的函数，并运行

(gdb) b kslwtbctx
Breakpoint 1 at 0x8f9a5c2
(gdb) c
Continuing.

6、查等待事件kslwtbctx函数的第一个参数，用命令info all-register显示寄存器

(gdb) info all-register
rax            0x62657100       1650815232
rbx            0x15c    348
rcx            0x0      0
rdx            0x1      1
rsi            0x7a59   31321
rdi            0x7fff1c576d40   140733668879680
rbp            0x7fff1c576ce0   0x7fff1c576ce0
rsp            0x7fff1c576ce0   0x7fff1c576ce0
r8             0x2      2
r9             0x25     37
r10            0x7      7
r11            0x0      0
r12            0x0      0
r13            0xbb0c348        196133704
r14            0xbb09d40        196123968
r15            0x1      1
rip            0x8f9a5c2        0x8f9a5c2 
eflags         0x246    [ PF ZF IF ]
cs             0x33     51
ss             0x2b     43
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0
st0            0        (raw 0x00000000000000000000)
---Type  to continue, or q  to quit---
st1            0        (raw 0x00000000000000000000)
st2            0        (raw 0x00000000000000000000)
st3            0        (raw 0x00000000000000000000)
st4            0        (raw 0x00000000000000000000)
st5            0        (raw 0x00000000000000000000)
st6            73280    (raw 0x400f8f20000000000000)
st7            73280    (raw 0x400f8f20000000000000)
fctrl          0x27f    639
fstat          0x0      0
ftag           0xffff   65535
fiseg          0x0      0
fioff          0x9394e95        154750613
foseg          0x7fff   32767
fooff          0x1c573f50       475479888
fop            0x0      0

8、用x/32命令查内存中32个字节

gdb) x/32 0x7fff1c576d40
0x7fff1c576d40: 0x1c577a59      0x00007fff      0x1c576e50      0x00007fff
0x7fff1c576d50: 0x1c576ee0      0x00007fff      0x0918adf2      0x00000000
0x7fff1c576d60: 0x00000000      0x00000000      0x00000000      0x00000000
0x7fff1c576d70: 0x00000000      0x00000001      0x00000000      0x00000000
0x7fff1c576d80: 0x002adb17      0x00000000      0x00000000      0x00000000
0x7fff1c576d90: 0x00000000      0x00000000      0x00000001      0x00000000
0x7fff1c576da0: 0x09b958cc      0x00000000      0x0000015c      0x00000000
0x7fff1c576db0: 0x7fffffff      0x00000000      0x62657100      0x00000000

9、找到0x0000015c，通过此等待事件号，找等待事件

gyj@OCM> select  name from v$event_name where event# in(select to_number('15c','xxxxxxxxxxxxxx') from dual);


NAME
----------------------------------------------------------------
SQL*Net message to client

10、重复第5、6、7、8、9步(注用从第5步的c命令开始）

(gdb) c
Continuing.

Breakpoint 1, 0x0000000008f9a5c2 in kslwtbctx ()
(gdb) info all-register
rax            0x0      0
rbx            0x2000   8192
rcx            0x0      0
rdx            0x0      0
rsi            0x0      0
rdi            0x7fff1c574c38   140733668871224
rbp            0x7fff1c574970   0x7fff1c574970
rsp            0x7fff1c574970   0x7fff1c574970
r8             0x5bbb295        96187029
r9             0x2f8b5f0        49853936
r10            0x52da848e       1390052494
r11            0x2b0b9057e7a8   47328666314664
r12            0x99837da8       2575531432
r13            0x0      0
r14            0x0      0
r15            0x99437498       2571334808
rip            0x8f9a5c2        0x8f9a5c2 
eflags         0x246    [ PF ZF IF ]
cs             0x33     51
ss             0x2b     43
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0
st0            0        (raw 0x00000000000000000000)
---Type  to continue

gdb调试之--readbyothersession等待事件的重现(二)