详解Oracle中的隐含参数_disable_logging

SQL> select ksppinm,ksppdesc from x$ksppi where ksppinm like '%logging';

KSPPINM    KSPPDESC
-------------------- ------------------------------
_disable_logging  Disable logging

[oracle@jumper bdump]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Wed Oct 19 11:01:19 2005

Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.


Connected to:
Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production
With the Partitioning option
JServer Release 9.2.0.4.0 - Production

SQL> alter system set "_disable_logging"=true scope=both;

System altered.

SQL> create table t as select * from dba_users;

Table created.

SQL> select count(*) from t;

 COUNT(*)
----------
  12

SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 97588504 bytes
Fixed Size     451864 bytes
Variable Size    33554432 bytes
Database Buffers   62914560 bytes
Redo Buffers     667648 bytes
Database mounted.
Database opened.
SQL> select count(*) from t;
select count(*) from t
      *
ERROR at line 1:
ORA-00942: table or view does not exist

Wed Oct 19 20:38:38 2005
Beginning crash recovery of 1 threads
Wed Oct 19 20:38:38 2005
Started first pass scan
Wed Oct 19 20:38:39 2005
Completed first pass scan
 0 redo blocks read, 0 data blocks need recovery
Wed Oct 19 20:38:39 2005
Started recovery at
 Thread 1: logseq 2, block 201, scn 0.897632464
Recovery of Online Redo Log: Thread 1 Group 1 Seq 2 Reading mem 0
 Mem# 0 errs 0: /opt/oracle/oradata/conner/redo01.log
Wed Oct 19 20:38:39 2005
Completed redo application
Wed Oct 19 20:38:39 2005
Ended recovery at
 Thread 1: logseq 2, block 201, scn 0.897652465
 0 data blocks read, 0 data blocks written, 0 redo blocks read
Crash recovery completed successfully