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Roger Macnicol

Software Architect

New in 18c: Introduction to In-Memory External Tables in 18c

On June 10th 2014, Larry Ellison officially launched the new Oracle Database In-Memory option which introduced revolutionary dual-format storage to access the...

Introduction to In-Memory External Tables (IMXT )

This article has been moved to the Oracle Database In-Memory blog

Create External Table as Select

I was looking through a test script and saw something I didn't know you could do in Oracle. I mentioned it to an Oracle ACE and he didn't know it either. I then...

Understanding External Table URowids

I finally found time to get back to External Tables and have a list of blog posts I need to write on this topic. Here's a brief one. DBMS_ROWID will nicely break...

How to tell if the Exadata column cache is fully loaded

When a background activity is happening on the cell you typically can't use RDBMS v$ views to monitor it in the same way. One such question is how to tell if a...

Revisiting buffer cache Very Large Object Threshold (VLOT)

If you turn on NSMTIO tracing you will see references to VLOT: qertbFetch:[MTT < OBJECT_SIZE < VLOT]: Checking cost to read from caches (local/remote) and...

Random thoughts on block sizes

I heard "Oracle only tests on 8k and doesn't really test 16k" I heard someone assert that one reason you should only use 8k block sizes is that, and I quote,...

External Tables Part 1: Project Columns All vs Referenced

I normally blog about table scans on Oracle native data but Oracle also supports a wide variety of features for scanning external tables and I need to cover...

The beginners guide to Oracle Table Scans

I was asked a question yesterday that reminded me there are always people completely new to the topic who need an introduction  - somewhere to start before the...