Monthly Archives: November 2012

tnsping and instant client

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Mostly when you install your instant client, you will not have tnsping handy. You could well try to copy it from a full client, but this is cumbersome to just ping your instance.

I just created one function in my .profile


whence tnsping >/dev/null 2>&1 || 
  tnsping() { 
    sqlplus -L -s x/x@$1 </dev/null | 
      grep ORA- | 
        (grep -v ORA-01017 || echo OK)
  }

and tested it


$ tnsping db999
ORA-12154: TNS:could not resolve the connect identifier specified
$ tnsping db01
OK
$ tnsping db02
ORA-12541: TNS:no listener

Enhancement Request : SSL listener and OEM

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#em12c still does not support SSL ! Encrypting network connection (https, ssh, sftp) is common sense in today’s business.

In Enhancement Request 6512390, Created 19-Oct-2007, the customer requested support for SSL.

Most recent update : it is postponed to 13cR2 at least !

*** 09/14/12 04:04 am DISCUSSION ***As we kick off 13c release, cleaning up the ERs. Mass updating all 13%GC% ERs to fixby 13.2GC DEFER. If you want to implement ER in 13.1GC, please update the fixby to = 13.1GC, and update all the other fields as per guidelines published.

Considering the cost of oracle advanced security option (required to get ssl), the lack of ability to influence future product enhancement is disappointing

Create database link and logon trigger

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Today I could not understand why I was getting ORA-1031 with create database link.

After analysis, I found out a logon trigger that changed the current schema. As Tom always says, triggers are evil…

DEMO:


SQL> create user u1 identified by xxx;

User created.

SQL> grant create session, create database link to u2 identified by xxx;

Grant succeeded.

SQL> create trigger evil after logon on database  begin 
  2  execute immediate 'alter session set current_schema=u1';end;
  3  /

Trigger created.

SQL>
SQL> conn u2/xxx
Connected.
SQL> create database link l;
create database link l
                     *
ERROR at line 1:
ORA-01031: insufficient privileges

SQL> show user
USER is "U2"
SQL> select sys_context('USERENV','CURRENT_SCHEMA') from dual;

SYS_CONTEXT('USERENV','CURRENT_SCHEMA')
-----------------------------------------
U1

SQL> alter session set current_schema=u2;

Session altered.

SQL> create database link l;

Database link created.