Top 60 Oracle Blogs

Recent comments


Oracle 19c Automatic Indexing: CBO Incorrectly Using Auto Indexes Part II ( Sleepwalk)

As I discussed in Part I of this series, problems and inconsistencies can appear between what the Automatic Indexing processing thinks will happen with newly created Automatic Indexing and what actually happens in other database sessions. This is because the Automatic Indexing process session uses a much higher degree of Dynamic Sampling (Level=11) than other […]

Oracle 19c Automatic Indexing: Data Skew Part III (The Good Son)

  I’m going to expand just a tad on my previous posts on data skew and run a simple query that returns a few rows based on a column predicate AND another query on the same column that returns many rows. The following table has a CODE column as with previous posts with the data […]

Oracle 19c Automatic Indexing: Data Skew Part I (A Saucerful of Secrets)

When it comes to Automatic Indexes, things can become particularly interesting when dealing with data skew (meaning that some columns values are much less common than other column values). The next series of blog posts will look at a number of different scenarios in relation to how Automatic Indexing works with data that is skewed […]

Oracle 19c Automatic Indexing: Poor Data Clustering With Autonomous Databases Part I (Don’t Look Down)

I’ve discussed many times the importance of data clustering in relation to the efficiency of indexes. With respect to the efficiency of Automatic Indexes including their usage within Oracle’s Autonomous Database environments, data clustering is just as important. The following demo was run on an Oracle 19c database within the Oracle Autonomous Database Transaction Processing […]

Oracle 19c Automatic Indexing: Configuration (All I Need)

In this post, I’ll discuss how to configure the new Automatic Indexing capability introduced in Oracle Database 19c. The intent of Oracle here is to make the configuration of Automatic Indexing as simplistic as possible, with as few levers for DBAs to potentially stuff up as possible. The ultimate goal would be to have a […]

Oracle 19c Automatic Indexing: Methodology Introduction (After Today)

For the past month or so I’ve been playing around extensively with the new Oracle 19c “Automatic Indexing” feature, so I thought it was time to start blogging about it. Considering it’s only in “Version 1” status, my initial impression is very positive in that it works extremely well doing at what it’s initially designed […]