Top 60 Oracle Blogs

Recent comments

Oracle Indexes

Effective Indexing Webinar

Thanks to everyone for attending today's Effective Indexing webinar sponsored by IOUG with Embarcadero. For attendees, IOUG will likely send out a link to the recording and PDF of the presentation, but I also wanted to post it here.

Presentation PDF
Webinar recording

Index Rebuild, the Need vs the Implications Support Note 989093.1 (Getting Better)

Once upon a time, Oracle Support had a note called Script: Lists All Indexes that Benefit from a Rebuild (Doc ID 122008.1) which lets just say I didn’t view in a particularly positive light :) Mainly because it gave dubious advice which included that indexes should be rebuilt if: Deleted entries represent 20% or more of […]

Modify Primary Key Using Index (Learning To Fly)

One of the things I love about working with Oracle Database technologies is that there’s just so much one can learn. I make it an active goal of mine to try to learn something new at work each and every day, no matter how big or small. One of these days, I might blog about a presentation I put together […]

12c Enhanced Online Index DDL Operations (Lady Godiva’s Operation)

In my last couple of posts, I discussed how table partitions can be moved online since 12c, keeping all indexes in sync as part of the process. 12c also introduced enhancements to a number of index related DDL statements, removing blocking locks and making their use online and far less intrusive. The following commands now have a new ONLINE […]

12c Online Partitioned Table Reorganisation Part II (Move On)

In Part I, we looked at some of the issues associated with locking and unusable indexes when Moving both tables and table partitions. The Oracle 12c Database has introduced a number of great new capabilities associated with online DDL activities. One of these really useful features is the capability to now move table partitions online while […]

12c Online Partitioned Table Reorganisation Part I (Prelude)

First post for 2014 !! Although it’s generally not an overly common activity with Oracle databases, reorganising a table can be somewhat painful, primarily because of the associated locking implications and the impact it has on indexes. If we look at the following example: So we have a table with a couple of indexes. We […]

12c Invisible Columns (The Invisible Man)

Oracle 12c introduced the ability to make user specified columns “Invisible” such that they’re invisible by default and have to be explicitly referenced to be accessed. So a simple SELECT * won’t display columns defined as invisible, but they will be displayed if explicitly referenced in the SELECT column list. From an indexing perspective, columns […]

12c Indexing Extended Data Types Part II (15 Steps)

Finally, at long long last, I have a spare 30 minutes in my life to complete this blog entry !! As discussed previously, Oracle has extended the maximum length of varchar2, nvarchar and raw columns to 32K, but this comes with some challenges when it comes to indexing such columns due to restrictions on the […]

12c Indexing Extended Data Types Part I (A Big Hurt)

The maximum size for VARCHAR2, NVARCHAR and RAW columns has been extended to 32767 bytes with the Oracle 12c Database. However, indexing such columns with standard indexes comes with some challenges. These extended data types are not enabled by default within the database but can easily be done so by following these steps: Restart the […]

12c Asynchronous Global Index Maintenance Part III (Re-Make/Re-Model)

As I discussed previously in Part I, the space occupied by orphaned row entries associated with asynchronously maintained global indexes is not automatically reclaimed by subsequent DML operations within the index. Hence the need to clean out these orphaned index entries via the various options discussed in Part II. However, a good question by Jason […]