18c

Partition-wise operations are not something new. I do not remember when they were introduced, but at that time the release number was still a single digit. Anyway, the aim of this post is not to describe the basics, but only to describe what is new in that area in 12c and 18c.

The new features can be grouped in three categories:

• Partition-wise GROUP BY enhancements available as of version 12.2
• Partition-wise DISTINCT enhancements available as of version 12.2
• Partition-wise windowing functions enhancements available as of version 18.1

Before looking at the new features, here are the SQL statements I executed to create a partitioned table that I use through the examples. You can download the script here.

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 […]

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 […]

18.2 was released a few days ago, so I thought I’d throw it against my 18c instance and see how things played out.  This was just a single instance database, running with a single pluggable.

If you run TKPROF without arguments, you get a complete list of its arguments with a short description for each of them (here the output generated by version 18.1.0):

One of the potentially cool new features introduced in Oracle Database 18c is the Memoptimized RowStore, designed to improve the performance and scalability of key-value based queries. A new pool in the SGA called the Memoptimize Pool can be configured to store specific heap tables that you may wish to optimize, in a manner not […]

In the past I already shared with you the scripts I use to download the Oracle Database documentation. The aim of this short post is to reference the scripts I just wrote for 18c.

• download18.cmd
• download18.sh

Happy downloading as well as happy reading!

PS: I also refreshed the scripts for 12.1 and 12.2.

One of the cool things in 18c is the ability to merge partitions without causing a service interruption.  Here’s a video demonstration of that in action:

This is just an accompanying blog post to let you grab the scripts for the demo so that you can try this yourself on livesql.oracle.com, or any of the Oracle Cloud services that will be running 18c in the near future.

You’ve seen the tweet !!

but perhaps the accompanying blog post has tempered your enthusiasm

You might be thinking:

Yup…it’s arrived!

New name obviously, because we’ve jumped to our new naming model to align with the calendar year as opposed to version number.  You might be thinking “So what?” but it’s a significant change in the way we getting software to customer.  Mike Dietrich blogged about this at length here so I won’t repeat what has been said, but in TL;DR form:

More frequent releases, with smaller amounts of change per release

In this way, the approach lets us focus more of solidifying existing features, and being able to quickly respond to bugs that arise.

So 18c is more an incremental release on 12.2 (in fact, internally it was referred to as “12.2.0.2” for most of it’s build cycle) focussed on stability and hardening of existing features.