[20210203]19c登录连接改变一些参数.txt

--//昨天看了https://blog.dbi-services.com/19c-serverless-logon-trigger/,19c可以实现一种特殊的方式登录时直接改变oracle参

--//数.正好我们单位买了一台ODA,安装19c,可以测试看看.

1.环境:

> @ prxx

==============================

PORT_STRING                   : x86_64/Linux 2.4.xx

VERSION                       : 19.0.0.0.0

BANNER                        : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production

BANNER_FULL                   : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production

Version 19.9.0.0.0

BANNER_LEGACY                 : Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production

CON_ID                        : 0

PL/SQL procedure successfully completed.

2.测试:

> show parameter optimizer_mode

NAME           TYPE   VALUE

-------------- ------ ----------

optimizer_mode string ALL_ROWS

> connect sys/XXXXXYYY@(DESCRIPTION=(CONNECT_DATA=(SESSION_SETTINGS=(optimizer_mode=first_rows_10))(SERVER=DEDICATED)(SERVICE_NAME=dyhis))(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.99.46)(PORT=1521))) as sysdba

SYS@dyhis> show parameter optimizer_mode

NAME           TYPE    VALUE

-------------- ------- --------------

optimizer_mode string  FIRST_ROWS_10

--//通过连接串的SESSION_SETTINGS=(optimizer_mode=first_rows_10),改变了参数.

connect sys/XXXXXYYY@(DESCRIPTION=(CONNECT_DATA=(SESSION_SETTINGS=(sql_trace=true)(tracefile_identifier=franck))(SERVER=DEDICATED)(SERVICE_NAME=dyhis))(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.99.46)(PORT=1521))) as sysdba

SYS@dyhis> show parameter sql_trace

NAME      TYPE    VALUE

--------- ------- -------

sql_trace boolean TRUE

SYS@dyhis> select value from v$diag_info where name='Default Trace File';

VALUE

-------------------------------------------------------------------------

/u01/app/oracle/diag/rdbms/dyhis/dyhis2/trace/dyhis2_ora_29162_FRANCK.trc

--//查看跟踪文件无意间发现oracle的一个触发器:

=====================

PARSING IN CURSOR #140653736157352 len=391 dep=1 uid=0 oct=47 lid=0 tim=4805081161893 hv=2286069890 ad='b74dde98' sqlid='6s9sc8q445a42'

declare

pdb_name varchar2(64);

begin

DBMS_SYSTEM.get_env ('ORACLE_PDB_SID', pdb_name);

if(pdb_name is not null)

then

EXECUTE IMMEDIATE 'alter session set container = ' || '"' || pdb_name

|| '"';

end if;

exception

when others then

NULL;

end dbms_set_pdb;

END OF STMT

PARSE #140653736157352:c=29,e=29,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=4,plh=0,tim=4805081161893

EXEC #140653736157352:c=157,e=158,p=0,cr=0,cu=0,mis=0,r=1,dep=1,og=4,plh=0,tim=4805081162078

CLOSE #140653736157352:c=12,e=12,dep=1,type=1,tim=4805081162119

=====================

--//你可以定义一个环境变量ORACLE_PDB_SID,这样登录直接进入某个PDB数据库.

--//作者还提供查询支持那些功能的命令:

$ strings $ORACLE_HOME/bin/oracle | grep ^DESCRIPTION/CONNECT_DATA/ | cut -d/ -f3-

COLOCATION

SID

NUMA_PG

CID/PROGRAM

SESSION_SETTINGS

MODULE_NAME

MODULE_ACTION

SERVICE_NAME

GLOBAL_NAME

CID/USER

REGION

PRESENTATION

SERVER

DUPLICITY

SEPARATE_PROCESS

SERVER_WAIT_TIMEOUT

COMMAND

DESIG

ORACLE_HOME

FAILOVER_MODE

FAILOVER_MODE/BACKUP

SESSION_STATE

USE_DBROUTER

RPC

--//作者还给出一些例子不再测试了.