I had a very interesting case today when database hang and I was not able to make connection..

First thing I had in mind was to generate system state dumps.In the past I used debugger but I remember that sqplus has option which makes  database connection “light” meaning it doesn not create session but has limited access to SGA…

It has been arround since 10g…  It’s called preliminary connection.There are two options to :

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Trying to setup DRCP   11g patchset 11.1.0.6 on Linux x86-64..

The pool can be configured using the PLSQL package DBMS_CONNECTION_POOL.

First start connection pool ( I am using default parameters ):
 

SQL> execute dbms_connection_pool.start_pool;
PL/SQL procedure successfully completed.

Then simply change tnsnames.ora  and  set

SERVER=POOLED    Let’s try to connect
 
C:\Documents and Settings\admin>sqlplus system@demo11g
SQL*Plus: Release 10.2.0.1.0 – Production on Tue Sep 23 12:58:25 2008
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Enter password:
ERROR:
ORA-03135: connection lost contact
Enter user-name: system@demo11g
Enter password:
ERROR:
ORA-03135: connection lost contact
Enter user-name: system@demo11g
Enter password:
ERROR:
ORA-03135: connection lost contact
SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus

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When configuring data guard using DGMGRL utility

add database ‘boston’
as connect identifier is boston
maintained as physical;

I would get ORA-01017 invalid username/password error…

I realized that this is related to case sensitive passwords in 11g…

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