11g

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In parts 11 and 12 of this series I described the “rowsource execution statistics” that we can collect as Oracle runs a query, then described a strategy for generating and accessing these statistics in a way that was particularly convenient if you could use your own session to run the SQL you wanted to analyze. In this article we’re going… Continue Reading →

11g, 12c, All Things Oracle Full Articles, Database Administration, Database Development, Oracle Database

Rolling Forward a Physical Standby Database Using the RECOVER Command A standby database is a transactionally-consistent copy of the production database. It enables production Oracle database to survive disasters and data corruption. If the production database becomes unavailable because of a planned or an unplanned outage, Data Guard can switch a standby database to the production role, minimizing the downtime associated… Continue Reading →

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

Oracle Database 12c has new enhancements and additions in Recovery Manager (RMAN).  The Recovery Manager continues to enhance and extend the reliability, efficiency, and availability of Oracle Database Backup and Recovery. In this article series, I will be explaining the new features and how they help the Oracle community. See new features around SYSBACKUP, pluggable databases, and the SQL interface… Continue Reading →

11g, 12c, All Things Oracle Full Articles, Database Administration, Database Development

What is cloning? Cloning is a process of copying an existing installation to a different server or location. Cloning is similar to an Oracle installation except Oracle universal installation performs the actions in a special mode called “clone mode”. Starting from 10g onwards, Oracle supports cloning and users can easily clone existing Oracle installations. The source and destination servers should… Continue Reading →

10g, 11g, All Things Oracle Full Articles, Database Administration, Database Development

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

In this part of the series we will have a look at different approaches to how Parallel Execution Skew can be addressed via manual re-writes of an affected query. Let’s have a look at a couple of options. Approach 1: Mimic the new 12c skew aware feature Looking at the new 12c special skew aware distribution feature that I’ve introduced… Continue Reading →

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

After providing a baseline for Parallel Execution working as expected in the introduction of this series, in this part I’ll demonstrate how things can go wrong with the work distribution. A Simple Example Of Parallel Execution Skew One common source of Parallel Execution Skew is a skewed foreign key, which means that the value distribution of the foreign key column… Continue Reading →

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

When Oracle initially introduced the standby database concepts, the solo intention was to deliver the solutions to protect enterprise critical business data from any sort of natural and unnatural disasters. Since its innovation, Oracle has incorporated huge amount of new functionality/features and made several enhancements to ensure the standby database deliver and meet various user demands. This article is not… Continue Reading →

11g, All Things Oracle Full Articles, Database Administration

Insanity: doing the same thing over and over again and expecting different results. – Albert Einstein In part 1 we looked at the result cache for PL/SQL Code We can also use this same technique when our function depends on tables (or views). Let’s create a simple table, add some data and a simple, slow function: CREATE OR REPLACE FUNCTION… Continue Reading →

11g, 12c, All Things Oracle Full Articles, Database Development, Oracle Database, PL/SQL

First, solve the problem. Then, write the code. – John Johnson We are always looking for ways to do things faster. Sure you can use more CPU power or more memory in the database server, but there’s a limit to that approach. Be it the amount of money being spent, the limits of the [current] CPU power or other limits…. Continue Reading →

11g, 12c, All Things Oracle Full Articles, Database Development, Oracle Database, PL/SQL