Search

Top 60 Oracle Blogs

Recent comments

Oracle Cloud

Oracle 19c Automatic Indexing: Indexing Partitioned Tables Part I (Conversation Piece)

In this little series, I’m going to discuss how Automatic Indexing works in relation to Partitioning. I’ve discussed Indexing and Partitioning many times previously and how Oracle has various options when indexing a partitioned table: Non-Partitioned Index Globally Partitioned Index Locally Partitioned Index So the question(s) are how does Automatic Indexing handle scenarios with partitioned […]

Oracle 19c Automatic Indexing: Indexing With Stale Statistics Part III (Do Anything You Say)

In Part I of this series, we saw how Automatic Indexing will not create a viable Automatic Index if there are stale or missing statistics on the underlining segments. In Part II we saw how these SQL statements effectively become blacklisted and when segment statistics are subsequently collected, Automatic Indexing will still not create viable […]

Oracle 19c Automatic Indexing: Indexing With Stale Statistics Part I (Dead Against It)

A “golden rule” when working with Automatic Indexing is that things don’t work properly if there are stale statistics on the dependant objects. Stale statistics can of course be problematic but they can be particularly troublesome when dealing with Automatic Indexing. In the Oracle Autonomous Database environments, this issue is addressed somewhat by the new […]

Oracle 19c Automatic Indexing: Data Skew Fixed By Baselines Part II (Sound And Vision)

  In my previous post, I discussed how the Automatic Indexing task by using Dynamic Sampling Level=11 can correctly determine the correct query cardinality estimates and assume the CBO will likewise determine the correct cardinality estimate and NOT use an index if it would cause performance to regress. However, if other database sessions DON’T use […]

Oracle 19c Automatic Indexing: Data Skew Fixed By Baselines Part I (The Prettiest Star))

In my previous few blog posts, I’ve been discussing some issues in relation to how Automatic Indexes handle SQL statements that accesses skewed data. In this post, I’m going to setup the scenario in which Automatic Indexing can potentially use Baselines to help address some of these issues. BUT, as we’ll see, I’m having to […]

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 […]

SQL Server on Oracle Cloud

By Franck Pachot

.
You can create a VM with SQL Server running in the Oracle Cloud. This is easy with a few clicks on the marketplace:

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 […]

Observations About the Scalability of Data Loads in ADWC

In the last days, I am running a number of tests based on the TPC-DS benchmark against Oracle’s Autonomous Data Warehouse Cloud service (ADWC). One of the first thing I did is of course to create the TPC-DS schema and populate it. The aim of this blog post is to share some observations related to the population step.

I started by generating the data with the tool provided by TPC-DS: dsdgen. With the following command, I generated 1TB of data:

$ dsdgen -scale 1000 -dir /data/tpcdsdata

The tool generated, in about 24 hours, the following files:

Which Privileges Are Required to Use the ADWC Service Console?

The Autonomous Data Warehouse Cloud (ADWC) service provides a Service Console that can be used to monitor the service activity and to carry out a small number of administration tasks (e.g. changing some resource management rules).

The documentation specifically says to use the ADMIN user to login. But, actually, any unlocked database user having the CREATE SESSION privilege can be used to login. This is not only useful, but, in my opinion, necessary. In fact, developers should be able to see the service activity without knowing the password of the ADMIN user.