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AskDba.org Weblog » Archive for December 2008

Creating Oracle Extended RAC on Oracle VM

December 30th, 2008 | Add a Comment

Yesterday, I found one very useful article at OTN “Creating Oracle Extended RAC” on completely virtual environment using Oracle VM. As Virtualization is becoming popular day by day and is very cost effective, one must know how to use this to simulate actual environments. Click  here for details on Oracle Extended RAC on Oracle VM. … Read entire article »

Filed under: oracle, rac

Database Security: Transparent Data Encryption

December 19th, 2008 | 1 Comment

Data in the database is secured by using authentication, authorization and auditing mechanism, but the information stored in the datafiles can be read using any hex-editor tools or other OS level utilities, which is causing threat to sensitive  data. To overcome this limitation TDE is used to secure sensitive data, in database columns, stored in the datafiles. TDE is key-based access control mechanism. For each table, having encrypted column in it, an encryption key is generated which is again encrypted by database server’s master key. The database server’s master key is generated at the time when Wallet is ceated. The master key is stored outside oracle database in a Wallet and the keys for all tables containing encrypted columns are stored in dictionary tables in database. How to setup TDE: … Read entire article »

Filed under: database, oracle

Changes To 10g OCA Certification

December 18th, 2008 | 5 Comments

Changes To 10g OCA Certification

People planning to appear for  10g OCA Exam will be startled to find that they need to pass additional exam to get the certificate. Starting from December 1, 2008, in addition to the existing exam (Oracle Database 10g: Administration I (1Z0-042)), candidates are also required to pass any one of the four following Oracle SQL exams to earn the certification: Introduction to Oracle: SQL® and PL/SQL™ (1Z0-001) or, Introduction to Oracle9i: SQL (1Z0-007) or, Oracle Database … Read entire article »

Filed under: database, oracle

Index Access best approach?? Not Always…

December 17th, 2008 | 6 Comments

There is a common misconception that Index access is the best access method for query execution. This approach leads to people concentrate on removing Full Table Scans (FTS) from the Query execution plan. I recently worked on a performance tuning issue where I found such scenario. Basically customer was trying to generate report for 3 years and query was running for more then 8 hours without producing any results. We were asked to look into this problem. Following diagnostic data was collected to diagnose the issue. 1)    10046 trace at level 12 2)    Execution plan from V$SQL_PLAN (Database version is 9.2) 3)    Explain plan for offending query From 10046 trace and V$session_wait, I found out query was waiting on  “db file sequential read” wait event for table SCOTT_BILL. This indicated that we were reading this … Read entire article »

Filed under: oracle, performance