Announcement: Webinars for “Oracle Indexing Internals and Best Practices” Now Confirmed !!

Exciting News !! I can now confirm the dates for my first webinars of my fully updated and highly acclaimed “Oracle Indexing Internals and Best Practice” seminar. For details of all the extensive content covered in the webinars, please visit my Indexing Seminar page. The webinars will run for 4 hours each day, spanning a full week period […]

Announcement: Venue Confirmed For Upcoming Brussels “Oracle Indexing Internals and Best Practices” Seminar

I can finally confirm the venue for my upcoming “Oracle Indexing Internals and Best Practices” seminar in beautiful Brussels, Belgium running on 27-28 September 2018. The venue will be the Regus Brussels City Centre Training Rooms Facility, Avenue Louise / Louizalaan 65, Stephanie Square, 1050, Brussels. Note: This will be the last public seminar I’ll run […]

Rebuilding Indexes: Danger With Clustering Factor Calculation (Chilly Down)

Let me start by saying if you don’t already following Jonathan Lewis’s excellent Oracle blog, do yourself a favour. In a recent article, Jonathan highlighted a danger with rebuilding indexes (or indeed creating an index) when used in relation to collecting index statistics with the TABLE_CACHED_BLOCKS preference. I’ve discussed the importance of the TABLE_CACHED_BLOCKS statistics […]

Index Column Order – Impact On Index Branch Blocks Part II (The Weeping Song)

In Part I, I discussed how the order of columns in an index makes no real difference to the effectiveness of the index if all columns are referenced via equality predicates. If the leading column has a high number of distinct columns, it might result in less necessary data within index branches as less data […]

Announcement: New Europe Seminar in Brussels, Belgium 27-28 September 2018

Due to popular demand, I’ll be running another of my acclaimed seminars in Europe later in the year, this time in Brussels, Belgium on 27-28 September 2018. This is a must attend seminar of benefit to not only DBAs, but also to Developers, Solution Architects and anyone else interested in designing, developing or maintaining high […]

Index Column Order – Impact On Index Branch Blocks Part I (Day-In Day-Out)

I recently replied on Twitter to some comments regarding an excellent blog post by Franck Pachot – Covering indexes in Oracle, and branch size, where I disagreed somewhat with one of the conclusions stated in the post: “ensure that selective columns appear as early as possible (without compromising the index access efficiency of course) in order to […]

Announcing July/August Australian Dates: “Oracle Indexing Internals and Best Practices” Seminar

I’m very excited to announce new Australian dates for my highly acclaimed “Oracle Indexing Internals and Best Practices” seminar. This is a must attend seminar of benefit to not only DBAs, but also to Developers, Solution Architects and anyone else interested in designing, developing or maintaining high performance Oracle-based applications. It’s a fun, but intense, […]

18c Scalable Sequences Part III (Too Much Rope)

I previously looked in Part I and Part II how Scalable Sequences officially released in 18c can reduce index contention issues, by automatically assigning a 6 digit prefix to the sequence value based on the instance ID and session ID of the session. We need to be careful and consider this 6 digit prefix if […]

ODTUG Kscope18 Conference: Change of Presentation Times

For those of you that were planning to attend my presentations at the upcoming ODTUG Kscope18 Conference in Orlando (yes, I’m specifically talking to the two of you), both presentations have been allotted new times and locations. They are now confirmed as: New Indexing Features Introduced in Oracle 12c Release 2 (and 18c): When:  June […]

18c Scalable Sequences Part II (Watch That Man)

In Scalable Sequences Part I, I introduced this new 18c feature (although it was hidden and undocumented in previous releases). By adding a 6 digit prefix value that constitutes the first 3 digits for the Instance Id and the next 3 digits for the Session Id, it results in a sequence value that doesn’t always […]

“Let’s Talk Database” is Back !! Canberra/Sydney/Melbourne

Due to popular demand, I’ve been asked by Oracle to again run some “Let’s Talk Database” events this month. Dates and venues are as follows: Wednesday, 23 May – Canberra (Cliftons Canberra, 10 Moore St): Registration Link. Tuesday, 29 May – Melbourne (Oracle Melbourne Office, 417 St Kilda Road): Registration Link. Wednesday, 30 May – Sydney […]

18c Scalable Sequences Part I (Saviour Machine)

One of the problems with populating the value of a Primary Key (or some such), is that they can cause contention, especially in relation to indexes. By having an indexed value that monotonically increases, the right-hand most index leaf block is continually being accessed, which results in a “hot block”, which in turn results in […]

Europe June 2018 Seminars: Confirmed Venues for Oslo, Munich and Zürich

I’m very excited to confirm all venues for the European June 2018 dates of my popular “Oracle Indexing Internals and Best Practices” seminar. This is a must attend seminar of benefit to not only DBAs, but also to Developers, Solution Architects and anyone else interested in designing, developing or maintaining high performance Oracle-based applications. It’s […]

Answer: Anything Wrong With Query Performance? (Red Right Hand)

I of course attract a highly clever readership :). As some have commented, for a single table to require 1000+ consistent gets to retrieve 1000 rows implies that each row needs to be accessed from a different block. This in turn implies the Clustering Factor for this index to be relatively bad and the associated […]

Question: Anything Wrong With Query Performance? (Straight To You)

I have a query that runs pretty darn efficiently, here’s the setup: So the query basically returns 100 rows based on the CODE column and it does so using an index on CODE. The CBO has got the costings for this just about spot on. For 100 rows returned, it does so with just 105 […]