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Oracle 19c Automatic Indexing: Function-Based Indexes? Part II (If You Can See Me)

In my previous post, I discussed how Automatic Indexing does not currently support creating an index based on a function or expression predicate, even if it’s an equality predicate. You must manually create the associated function-based index. However, if you have access to the application, there’s a better strategy when frequently searching on a function-based […]

Oracle 19c Automatic Indexing: Function-Based Indexes? (No Plan)

I previously discussed how Automatic Indexing only currently supports Equality based predicates. The question I have today is does Automatic Indexing support function-based indexes? Let’s take a look. The below DAVID table has the key column NAME which is an effectively unique VARCHAR2 column: If we look at the current details of the table columns: […]

Oracle Database 19c Automatic Indexing: Invisible Indexes Oddity (Wild Eyed Boy From Freecloud)

There have been a couple of “oddities” in relation to both Oracle Autonomous Databases and Automatic Indexing behaviour that I’ve seen frequently enough now (on Oracle 19.5.0.0.0) to make it worth a quick blog article. The following is a simple test case that highlights both these issues. I’ll begin with a basic table, that has […]

Migrating Oracle Exadata Workloads to Azure- Storage Indexes

I’m about simplifying anything for customers as we bring over complex environments into Azure and Oracle databases running on Exadata is a big part of these challenges.  Decoupling the database from the engineered features is a crucial part of my work and with Oracle 19c, having customers running on the terminal release isn’t the only reason to upgrade if the database is on an earlier release.

As I’ve discussed in other posts, blogs and articles, I have numerous ways to address latency when losing cell node offloading, hybrid columnar compression (HCC), thin cloning with sparse clone, flash cache, flash logging, etc., but storage indexes are unique to Exadata that simply have no comparable work around.

Oracle Database 19c Automatic Indexing: Index Compression Update (New Morning)

  I was reminded in a recent comment by Rajeshwaran Jeyabal that I hadn’t updated my post on Automatic Indexing with Advanced Compression that’s in need of a couple of amendments. Initially when Automatic Indexing was released, the ability to set Advanced Compression was NOT included in the official documentation, although the EXEC DBMS_AUTO_INDEX.CONFIGURE( ‘AUTO_INDEX_COMPRESSION‘ […]

Oracle 19c Automatic Indexing: Non-Equality Predicates Part II (Let’s Spend The Night Together)

In my previous post in this series, I discussed out Automatic Indexing currently does not consider Non-Equality predicates. Automatic Indexing will index columns based only on Equality predicates. So how does Oracle handle the scenario when an SQL has a mixture of both Equality and Non-Equality predicates? I’ll begin by creating two very similar tables, […]

Oracle 19c Automatic Indexing: Non-Equality Predicates Part I (Lucy Can’t Dance)

  I’ve been waiting a while before posting a series on the various limitations associated with Automatic Indexing, in order to see how the feature matures over time. The following have all been re-tested post 1 January 2021 on the Autonomous ATP Database Cloud service, using Oracle Database version 19.5.0.0.0. In the Oracle Documentation (including […]

Oracle 19c Automatic Indexing: Indexing Partitioned Tables Part II (Neighbourhood Threat)

In my first post on Automatic Indexing on Partitioned Tables, I discussed how Automatic Indexing (AI) can now create a Non-Partitioned index if deemed the most effective indexing structure (this wasn’t supported when AI was initially released). A Non-Partitioned index is indeed likely the most efficient indexing structure if the underlying table has many partitions […]

Oracle database reliable message waits

This blog is about the oracle database wait event ‘reliable message’. It should be noted that normally, this should not be a prominent wait, and if it does so, the most logical cause would be something that is not working as it should, either by oversubscribing something or simply because of a bug.

The reliable message note on My Oracle Support provides a good description:
https://support.oracle.com/epmos/faces/DocContentDisplay?_afrLoop=34595019638128&id=69088.1&_afrWindowMode=0&_adf.ctrl-state=15ief27plw_97

Oracle database processes and waiting long in the supermarket

Hopefully I got your interest by the weird name of this blogpost. This blogpost is about sensible usage of an Oracle database. Probably, there are a lot of blog posts like this, but I need to get this off my chest.

A quote any starwars fan would recognise is ‘I sense a disturbance in the force’. I do, and I have felt it for a long time. This disturbance is the usage of the number of connections for a database. Because of my profession, this is the oracle database, but this really applies to the server-side of any client/server server processor running on at least (but probably not limited to) intel Xeon processors.

The disturbance is the oversubscription or sometimes even excessive oversubscription of database connections from application servers, or any other means of database processes that acts as clients. This means this does not exclude parallel query processes, in other words: this applies to parallel query processes too.