5. “We’re just ordinary people who apply the scientific
method to the things we can observe and measure”
Author: Jonathan Lewis
Technical reviewer: Tanel Poder
出典：Oracle Core: Essential Internals for DBAs and Developers
8. $ sqlplus neo/follow_the_white_rabbit
SQL*Plus: Release 11.2.0.2.0 Production on Tue Oct 16 09:56:00 2012
Copyright (c) 1982, 2010, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL>
9. SQL> create table agent(id number(10),name char(10));
Table created.
SQL> begin
for i in 1..10000000 loop
insert into agent(id, name) values(i, 'smith');
end loop;
end;
/ 2 3 4 5 6
PL/SQL procedure successfully completed.
SQL> commit;
Commit complete.
SQL>
10. SQL> set autotrace on
SQL> alter session set events '10046 trace name context forever, level 12';
Session altered.
SQL> select count(1) from agent;
COUNT(1)
----------
1000000
Execution Plan
----------------------------------------------------------
Plan hash value: 2571700340
--------------------------------------------------------------------
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
--------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 789 (1)| 00:00:10 |
| 1 | SORT AGGREGATE | | 1| | |
| 2 | TABLE ACCESS FULL| AGENT | 873K| 789 (1)| 00:00:10 |
--------------------------------------------------------------------
11. $ tkprof orcl_ora_3331.trc orcl_ora_3331_tkprof.txt
$ less orcl_ora_3331_tkprof.txt
…
SQL ID: guxtdnm3w68gr Plan Hash: 2571700340
select count(1)
from
agent
…
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
Disk file operations I/O 1 0.00 0.00
asynch descriptor resize 2 0.00 0.00
direct path read 97 0.00 0.03
SQL*Net message from client 2 0.00 0.00
![#0 [e2694a6c] schedule at c061d348
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/kernel/sched.c: 2056
#1 [e2694ae4] io_schedule at c061d9f9
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/kernel/sched.c: 4879
#2 [e2694af0] sync_buffer at c04788c6
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/fs/buffer.c: 67
#3 [e2694af4] __wait_on_bit at c061dbd2
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/kernel/wait.c: 169
#4 [e2694b0c] out_of_line_wait_on_bit at c061dc57
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/kernel/wait.c: 182
#5 [e2694b44] __wait_on_buffer at c0478843
include/linux/wait.h: 434
#6 [e2694b50] __bread at c04799d6
include/linux/buffer_head.h: 318
#7 [e2694b58] ext3_get_branch at f8882927
#8 [e2694b78] ext3_get_blocks_handle at f8882ba4 ファイルシステム
#9 [e2694c34] ext3_get_block at f888369b
#10 [e2694c6c] do_mpage_readpage at c0495a48
...
#20 [e2694f8c] vfs_read at c0476536 VFS
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/fs/read_write.c: 264
#21 [e2694fa4] sys_pread64 at c0476a4f sys_pread64
/usr/src/debug/kernel-2.6.18/linux-2.6.18.i686/fs/read_write.c: 393
#22 [e2694fb8] system_call at c0404f10 pread64](https://image.slidesharecdn.com/dbts2012unconferencewttrwyazekatsupublish-121019002352-phpapp02/85/Dbts2012-unconference-wttrw_yazekatsu_publish-32-320.jpg)
![crash> set 3331
PID: 3511 TASK: f58c3550 CPU: 0 COMMAND: "oracle"
#0 [e70b4e90] schedule at c061d348
#1 [e70b4f08] pipe_wait at c0481408
#2 [e70b4f28] pipe_readv at c0481b16
#3 [e70b4f74] pipe_read at c0481ba2
#4 [e70b4f84] vfs_read at c0476536
#5 [e70b4f9c] sys_read at c0476981
#6 [e70b4fb8] system_call at c0404f10
EAX: ffffffda EBX: 00000009 ECX: 117efa5e EDX: 00002010
DS: 007b ESI: 117e6c28 ES: 007b EDI: bf923454
SS: 007b ESP: bf923414 EBP: bf923434
CS: 0073 EIP: 00c05402 ERR: 00000003 EFLAGS: 00000246
crash> dis e70b4fb8 10
dis: WARNING: e70b4fb8: no associated kernel symbol found
0xe70b4fb8: pop %ss
0xe70b4fb9: dec %edi
0xe70b4fba: inc %eax
ニーモニック、アセンブラコード
0xe70b4fbb: rorb $0x0,(%ecx)
0xe70b4fbe: add %al,(%eax)
0xe70b4fc0: pop %esi コンピュータが実行可能な機械語(マ
0xe70b4fc1: cli シン語)のプログラムを、人間が理
0xe70b4fc2: jle 0xe70b4fd5 解・記述しやすいように簡略化した英
0xe70b4fc4: adc %ah,(%eax) 単語や記号の組み合わせに置き換えた
0xe70b4fc6: add %al,(%eax) もの](https://image.slidesharecdn.com/dbts2012unconferencewttrwyazekatsupublish-121019002352-phpapp02/85/Dbts2012-unconference-wttrw_yazekatsu_publish-34-320.jpg)
