Back when Oracle Database 12.2 was released one of the new features of Database In-Memory was In-Memory Expressions. I wrote a three part series (Part 1, Part 2, Part 3) describing the details of In-Memory Expressions and if you’re interested I would recommend taking a look at those blog posts. There are examples to help illustrate the advantages they provide.
In Part 1 I described In-Memory Expressions (IM expressions) as providing the ability to materialize simple expressions and store them in the In-Memory column store (IM column store) so that they only have to be calculated once, not each time they are accessed. What makes this even more interesting in Oracle Database 21c is that several features use the underlying IM expressions infrastructure. In my post on Oracle Database 21c and Database In-Memory I briefly described the new features, and In-Memory Spatial, In-Memory Full Text Columns and In-Memory Support for the new JSON data type all leverage IM expressions.
In upcoming blog posts I will explore each of these new features and I will point out how IM expressions are used to implement these new features.
Original publish date: 09/27/2021