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It’s time to move away from the shape of an execution plan and turn our attention to some of the numerical information we get from the plan. In this article we’re going to look only at the predictions that the optimizer makes (explain plan), postponing any investigation of actual run-time figures (v$sql_plan_statistics_all) for future instalments. Getting Started As a reference… Continue Reading →

All Things Oracle Full Articles, Database Administration, Oracle Database

In Part 1, I described how data security is critical to the modern enterprise business world and the key role it plays, as well as some of Oracle 12c’s security features.  In Part 2, I am going to touch how to apply security controls in network, storage and backup levels. Also, a few selective Oracle database 12c new security features… Continue Reading →

12c, All Things Oracle Full Articles, Database Administration, Oracle Database

In the final part of this series I want to cover one last source of Parallel Execution Skew: Skew caused by Outer Joins. If you have Outer Joins where the majority of foreign key values is NULL, this can lead to the following symptoms: From a processing point of view for a parallel outer join, the NULL value in the foreign… Continue Reading →

10g, 11g, 12c, All Things Oracle Full Articles, Database Administration, Database Development, Oracle Database, Performance Tuning, Troubleshooting

When we examine an execution plan, we’re usually trying to work out the mechanical steps that Oracle took to produce a result set. When we do this, it’s important to remember that the text that Oracle optimized wasn’t necessarily the same as the statement we originally wrote. Oracle may have transformed our statement before passing it through the optimization engine…. Continue Reading →

All Things Oracle Full Articles, Database Administration, PL/SQL

Oracle Database 12c is designed for the cloud and introduces Multitenant Architecture with more than 500 new features. It enables customers to make more efficient use of their resources and reduce IT costs. What is Multitenant Architecture? Oracle 12c now introduces multitenant architecture featuring pluggable databases, which makes it easy to consolidate your databases on to the cloud, deliver high… Continue Reading →

12c, All Things Oracle Full Articles, Database Administration, Oracle Database

In part 5 of this series we examined a couple of examples where you had to handle the “first child first” rule with a little care. In part 6 we continue this exploration to look at a general principle – the “pushed subquery” – where the “first child first” could lead you to the wrong conclusion. Access or Filter If… Continue Reading →

All Things Oracle Full Articles, Database Administration, Database Development

I’ve offered up “first child first, recursive descent” as a basic strategy for interpreting execution plans – but it’s not a perfect rule, and it can be easy to lose track of what’s going on even when the basic “first child first” is being obeyed. In this article we’ll be looking at a couple of examples where we will still… Continue Reading →

12c, All Things Oracle Full Articles, Database Administration, Oracle Database

 1.   Introduction When a critical report which used to complete very quickly starts performing poorly, there is a big chance that the generic reason for this time response degradation is due to a change in an execution plan. If you want to avoid this flip-flop on plan and execution time you have at your disposal a feature called SQL Plan… Continue Reading →

All Things Oracle Full Articles, Database Administration, Database Development

Securing enterprise business-critical data is as important for DBAs as database tuning and data protection. Oracle provides comprehensive and powerful security controls/solutions to ensure data privacy and data security which will help with meeting regulatory compliance. Oracle supports the following security controls: Data Masking Advance Security (TDE, Data Redaction) Label security Virtual Private Database (VPD) Fine Grained Auditing (FGA) Data… Continue Reading →

12c, All Things Oracle Full Articles, Database Administration, Database Development

A wise man* once said, all software programming is about hoops and loops. You take some variables, give them hoops to jump through and, depending on their success or failure, you give them some actions to loop through a number of times. Might sound basic, but that’s what all software code – from Angry Birds to the space shuttle –… Continue Reading →

All Things Oracle Full Articles, Database Administration, PL/SQL