oracle 9i學習日誌（7）—診斷文件與練習3

診斷文件:包括數據庫發生的重大事件的信息；用來幫助解決問題和更好的維護數據庫。

類型：alertSID.log；後臺跟蹤文件（Background trace files）；用戶跟蹤文件（User trace files）。

1、以下操作或事件將被記錄在alertSID.log文件：

    數據庫啓動或關閉；

    非默認值的參數列表（包括參數名稱和參數值，在spfile或pfile損壞時可以藉助這些信息從新構造spfile或pfile）；

    啓動後臺進程；

    被instance所用的線程；

    The log sequence number LGWR is writing to；

    有關log調整的信息；

    創建表空間和undo segment；

    已經提交的alter語句；

    錯誤信息，如：ORA-600；

alter_SID.log所在位置由參數BACKGROUND_DUMP_DEST值定義。

 

2、後臺跟蹤文件（Background trace files）：

記錄當後臺程序出現重大錯誤時的信息。一般命名爲sid_processname_PID.trc。所在位置由參數

BACKGROUND_DUMP_DEST值定義。

實驗：

SQL> show parameter background_dump_dest

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
background_dump_dest                 string      /u01/admin/lty/bdump

$ cd /u01/admin/lty/bdump
[oracle@localhost bdump]$ ls -l
total 828
-rw-r--r-- 1 oracle oinstall 142968 Mar  6 23:38 alert_lty.log
-rw-r----- 1 oracle oinstall 660699 Mar  3 17:11 lty_d000_3303.trc
-rw-r----- 1 oracle oinstall    779 Feb 23 09:59 lty_qmn0_3324.trc
-rw-r----- 1 oracle oinstall    802 Feb 23 10:05 lty_qmn0_3338.trc
-rw-r----- 1 oracle oinstall    803 Feb 23 10:10 lty_qmn0_3350.trc

 

3、用戶跟蹤文件（User trace files）:

由用戶進程產生，也可以被server進程生成，包含跟蹤SQL語句的統計信息和記錄用戶會話錯誤信息。可以用來對SQL的調優和排錯。

命名規則一般爲：sid_ora_PID.trc(如：db01_ora_23845.trc)，所處位置由參數USER_DUMP_DEST決定，文件大小由參數MAX_DUMP_FILE_SIZE決定。

啓用和關閉用戶跟蹤

用戶級別：ALTER SESSION SET SQL_TRACE = TRUE啓用（注意：要在當前session設定）。也可以使用DBMS程序dbms_system.SET_SQL_TRACE_IN_SESSION。

instance級別：SQL_TRACE = TRUE啓用（會產生大量信息記錄，需謹慎）。

實驗：

客戶端：

sqlplus system/oracle@xxxx

SQL> alter session set sql_trace = true;

服務器：

$ ps -ef |grep oracle

oracle    3575  3574  0 00:57 ?        00:00:00 oraclelty (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

$cd /u01/admin/lty/udump

$ls –l

total 0

客戶端：

SQL> select * from dual;

服務器：

$ls –l

total 4
-rw-r----- 1 oracle oinstall 1383 Mar  7 00:58 lty_ora_3575.trc

 

4、Practice 3: Managing an Oracle Instance
1 Connect to the database as user SYS and shut down the database.
2 With the database shut down, create an SPFILE from the PFILE. The SPFILE will be created in $ORACLE_HOME/dbs.

  解析：SQL> create pfile from spfile;

   
3 From the operating system, view the SPFILE.

解析：

[oracle@localhost ~]$ cd dbs
[oracle@localhost dbs]$ ls -l
total 48
-rw-r--r-- 1 oracle oinstall 12920 Feb 22 20:14 initdw.ora
-rw-r--r-- 1 oracle oinstall  8475 Feb 22 20:14 init.ora
-rw-r----- 1 oracle oinstall    24 Mar  7 02:07 lkLTY
drwxr-xr-x 2 oracle oinstall  4096 Feb 22 16:29 old
-rwSr----- 1 oracle oinstall  1536 Feb 22 20:14 orapwlty
-rw-r----- 1 oracle oinstall  3584 Feb 22 20:14 spfilelty.ora

$strings spfilelty.ora

4 Connect as user SYS, and start the database using the SPFILE.
5 a Shut down the database and open it in read-only mode.

解析：SQL> startup mount

        SQL> alter database open read only;

b Connect as user HR password HR and insert a row into the REGIONS table as
follows:
INSERT INTO regions VALUES (5, 'Mars');
What happens?

解析：HR默認爲鎖定狀態，SQL> select username, user_id, account_status from dba_users;

         USERNAME                          USER_ID ACCOUNT_STATUS
        ------------------------------ ---------- --------------------------------
         HR                                     47 EXPIRED & LOCKED

        解鎖，SQL> select  username, account_status from dba_users;

        USERNAME                       ACCOUNT_STATUS
       ------------------------------ --------------------------------
        HR                             EXPIRED

       設置密碼,SQL> alter user hr identified by hr;

       查看狀態，SQL> select username, account_status from dba_users;

       USERNAME                       ACCOUNT_STATUS
       ------------------------------ --------------------------------
        HR                             OPEN

       

        另創建用戶lll密碼lll，SQL> create user lll identified by lll;

        以HR登陸後創建表lll,SQL> create table lll(num integer, name char(10));

       插入行，SQL> insert into lll values(0, 'lll');

                   ERROR 位於第 1 行:
                  ORA-00604: error occurred at recursive SQL level 1
                  ORA-16000: database open for read-only access

c Put the database back in read-write mode.
6 a Connect as user HR password HR and insert the following row into the REGIONS
table; do not commit or exit.
INSERT INTO regions VALUES (5, 'Mars');
b In a new telnet session start SQL*Plus. Connect user SYS and perform
a SHUTDOWN TRANSACTIONAL.
c Roll back the insert in the HR session and exit.
What happens to the HR session?
What happens to the SYS session?
7 a In the user SYS session start the database.
b In the open telnet session start SQL*Plus and connect as user HR.
Note: Keep the two SQL*Plus sessions open, one session as user SYS and one as
user HR.
c As user SYS enable a restricted session.
d As user HR, SELECT from the REGIONS table. Is the SELECT successful?
e Exit the session, then reconnect as HR. What happens? The user HR does not have
RESTRICTED SESSION privilege, and therefore, cannot log in.
f As user SYS disable the restricted session.
g Exit the HR telnet session

解析：SQL> alter system enable restricted session;

在數據庫置於restricted狀態時，不會中斷已連接用戶的會話。

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