The Spoken Nerd
Back to basics: The very clever history of the ROWID

Back to basics: The very clever history of the ROWID

February 15, 2021

The ROWID underpins many forms of data access within the Oracle Database. If you're a newcomer to Oracle, querying the rowid from a table returns a cryptic string such as "AAAhDyABAAABd0SAAA". But head back into the earlier versions of the database, and querying the rowid would return a completely different format like "0005DD12.0000.0040". In this episode, I'll cover what the rowid is, why the format of the rowid has evolved over the years, and reveal the extremely clever way this evolution occurred - an evolution that allowed the rowid to store more information in the same number of bytes, and as a result, gave rise to multi-petabyte databases.

You can also get a video version of the details in this episode on my YouTube channel here 

Back to basics: The evolution of tablespaces

Back to basics: The evolution of tablespaces

February 5, 2021

A tablespace is just a logical grouping of files in your Oracle database. But behind that simple definition sits a remarkable evolution of how tablespaces are defined and managed internally. This episode covers the early days of tablespaces and the pitfalls with managing their space utilisation from within the data dictionary. Then we'll move into the changes and improvements that with Oracle 8i and 8i. Finally we cover some of the more niche tablespace types that you may possibly have never used or even heard of. This episodes also sets you up for the big topic to cover in the next episode ... the ROWID.

Catch me on Twitter at https://twitter.com/connor_mc_d if you have questions.

How does SELECT * FROM TABLE find its data? Back to basics with datafiles, segments and extents

How does SELECT * FROM TABLE find its data? Back to basics with datafiles, segments and extents

January 16, 2021

The beauty of databases is they we just throw SQL at it, and it handles all the heavy lifting of working out where your data is, and how best to find it. But even for the novice, it is useful to know the fundamental mechanisms in which data is stored. In this episode, I cover datafiles, segments, extents and how your queries translate to the data physically stored on disk. Finally I'll go through how all of that applies when it comes running a basic SELECT statement to scan a table - how does the database locate your data? Catch me on twitter https://twitter.com/connor_mc_d if you have questions.

“Start the database!” is an incorrect phrase. Back to basics with databases and instances

“Start the database!” is an incorrect phrase. Back to basics with databases and instances

January 16, 2021

On StackOverflow, I chanced upon a beginner being trolled as they struggled to get going with Oracle. "Duh! Just start the database" someone said dismissively. I called out the rudeness by replying: "You don't start a database, you start an instance". So lets go back to basics, and describe Oracle in its most fundamental terms: What is a database? What is an instance? And why its important to understand the difference.  Catch me on Twitter at https://twitter.com/connor_mc_d

Introducing: The Spoken Nerd with Connor McDonald

Introducing: The Spoken Nerd with Connor McDonald

January 16, 2021

The Spoken Nerd is all about database tech from Connor McDonald - a database tech who has spent 20+ years working with database tech! Ever being frustrated as a child with the limits of 1 KB of RAM in his Sinclair ZX80 computer, Connor has loved the challenges that come with storing data. When the infamous Y2K did not end the world as people thought, he started presenting at conferences and now in our virtual-dominated world, a podcast seemed the perfect fit.

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