World of Oracle DBA

Problem Scenario You have cold backup of oracle database directory structure along with oracle software. Now your Windows OS got corrupted. So you reinstall your windows operating system and you try to restore the database. After installing software you set the ORACLE_SID and ORACLE_HOME environmental variable and whenever you create oracle service with oradim it fails with below message. C:\>oradim -new -sid orcl -intpwd orcl -startmode manual -pfile 'F:\oracle10g\pr oduct\10.2.0\db_1\database\initorcl.ora' Instance created. DIM-00019: create service error O/S-Error: (OS 2) The system cannot find the file specified. Solution of the Problem On linux environment you don't need these things. But in windows environment you need to do a lot of things more than restoring files. Whenever a windows OS gets corrupted you loose the Oracle Universal Installer repository and the regedit entries along with oracle home structure. So to solve the problem it is better to install new o

Problem Description While creating a startup database using dbca the database creation GUI gives error message in a pop up window, ORA-00845: MEMORY_TARGET not supported on this system from where you can ignore the error message. The similar scenario also occur whenever you try to start your database then startup shows error message like below. SQL> STARTUP ORA-00845: MEMORY_TARGET not supported on this system Cause of the Problem •Starting from Oracle 11g the automatic memory management feature is now defined with parameter MEMORY_TARGET and MEMMORY_MAX_TARGET. •On linux file system the shared memory need to be mounted on /dev/shm directory on the operating system. •And the size of /dev/shm needs to be greater than MEMORY_TARGET or MEMMORY_MAX_TARGET. •The AMM (Automatic Memory Management) now in 11g manages both SGA and PGA together by MMAN process. •The MEMORY_TARGET parameter in 11g comes for (SGA_TARGET+PGA_AGGREGATE_TARGET) which was in 10g. •And MEMORY_MAX_TARGET parameter in

Problem Description You are trying to create or drop a database link to the same database name. This may be true if you have a database that was cloned from another database on a different machine and now you try to create or drop a database link with the name of the original database. Below is an example. SQL> create database link tiger; create database link tiger * ERROR at line 1: ORA-02082: a loopback database link must have a connection qualifier SQL> drop database link tiger; drop database link tiger * ERROR at line 1: ORA-02082: a loopback database link must have a connection qualifier Cause of the Problem This is an expected behavior if database global name match with the database link creation name. Now let's see the global_name of the database. SQL> select * from global_name; GLOBAL_NAME --------------------------------------- TIGER.REGRESS.RDBMS.DEV.US.ORACLE.COM We see the global name of the database is started with

Problem Description In the database I have created one procedure named a as below. create or replace procedure a(a number) as begin insert into t1 values(1); commit; end; / Now after creating database link using remote database machine whenever I access this procedure "A" it executes successfully and I get value "1" in table t1. Like below in example where orastdby_m is the database link, maestro is the schema name and value 1 is the argument value though argument value is not used in the procedure. SQL> exec maestro.a@orastdby_m(1); PL/SQL procedure successfully completed. Now in the source database machine I changed the procedure as below. Though you can change anything like any literal; adding space or remove space. I changed value to be inserted from 1 to 2. create or replace procedure a(a number) as begin insert into t1 values(2); commit; end; / Now in the other database whenever I execute the procedure using database link it throws error ORA-04062. But su