As an “Oracle DBA ” normally interviewer ask about ORA-01555 snapshot too old error. What is Undo? Oracle Database maintain information that is used to roll back, or undo. Such information consists of records of the actions of transactions, primarily before they are committed. These records are collectively referred to as undo. Undo records are used to: 1. Roll … Read more
Source Database Name is PRODDB Target (duplicate) Database name is MYDB Source Host Name : server1.localdomain Target Host Name : server2.localdomain Put Database in archivelog mode. Step 1: Configure listener.ora and tnsnames.ora files Step 2: Create pfile for target database from Source database Step 3: Create password file Step 4: SCP passwordfile & pfile to target … Read more
Check the status of ASM instance . Check the database version and its status. Check ASM disk name available from the instance which we created earlier If you are using a spfile, take a backup of spfile using rman to restore it to ASM disk. Now restore the spfile from the backup to ASM disk as … Read more
When we run SQL tuning advisor against a SQL statement or sql_id, it provides tuning recommendations that can be done that query to improve performance. It might give suggestion to create few indexes or accepting a SQL profile. Suppose the sql id is – 72nggna3640qk 1. Create Tuning Task 2. Execute Tuning task: 3. Tuning … Read more