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November 2020

Ansible tips’n’tricks: using the OCI Dynamic Inventory Plugin in playbooks

After having covered how to configure the Ansible Dynamic Inventory Plugin for Oracle Cloud Infrastructure (OCI) in the previous posts now it’s time to get it to work with my simple-app cloud application. Before I go into more detail, I’d like to add the usual caveat first.

Video : CURSOR_SHARING : Automatically Convert Literals to Bind Variables in SQL Statements

In today’s video we’ll discuss the CURSOR_SHARING parameter, which determines how the database handles statements containing literal values.

The video is based on this article.

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Friday Philosophy – My First Foray Into I.T

This is the first ever computer I used. The actual one. It is a Sinclair ZX Spectrum 48K. It was at the heart of a long, terrible family feud, the source of much angst, anger, and even fist fights. Blood was spilt over this machine. Literally!

SQL Macros = SQL Injection ?

In my recent post about SQL Macros and their availability in 19c, I had some comments about parameter passing, these comments being related to a more general discussion what typically comes down to:

“Hmmmm … if we are changing the text of the SQL, and that change might be done based on user provided parameters, are we not just opening the door very very wide open and inviting Mr SQL Injection to the party?”

For example, consider a very trivial SQL Macro that just does some combining of two columns with a nominated separator.  (We obviously do not need a macro to achieve this, but it will let us illustrate an important point).

Ansible Dynamic Inventory Plugin for OCI: where are all my hosts?

I wrote about the configuration of the Ansible Dynamic Inventory Plugin for Oracle Cloud Infrastructure (OCI) in a previous post. As it seems to happen all the time, the length of the post escalated quickly. When I finished the previous post there was still a lot to say! For example, I wanted to share the answer to the question where all my hosts were hiding :)

rowsets

Here’s a little demonstration of the benefit of rowsets. It started with a very simple question that arrived in my in-box from Kaley Crum.

  • “Why does the query with the UNION ALL take so much longer than the query without the UNION ALL?”

Here are the two queries – surely they should take virtually the same amount of time.

Indexing partitions

This is one of those notes on the “thinking about the data / indexes” theme that I like to write; it’s a draft I wrote over two and a half years ago that I’ve just rediscovered and polished slightly and refers to a “recent” question that came up on the ODC Forum. It’s not intended as “The Answer” to the question, it’s a just a list of ideas and observations you’d want to think about if you had to address the problem:

Azure IO Performance for the RDBMS DBA- Part I

With my upcoming session on “Migrating Oracle Workloads to Azure IaaS” this week at PASS Virtual Summit 2020, I wanted to take some time to dig deeper onto the performance side. The last thing you want to have happen is to migrate your database to the cloud and have it just screech to a halt.

Ansible tips’n’tricks: configuring the dynamic inventory plugin for Oracle Cloud Infrastructure

As yet another preparation for a talk I’m about to give later this year I ran into a documentation bug concerning the use of the Ansible Dynamic Inventory plugin for Oracle Cloud Infrastructure. It has since been fixed, but it prompted me to write the entire procedure down anyway as I couldn’t really make sense of it at first. That’s probably more of a reflection on me than on the docs, which I found generally to be quite good.

My environment

In case you find this post via a search engine, this is the kit I was using when I put this post together:

Quiz time

Here’s a fun little item that I’ve just rediscovered from 2016.

There’s a fairly commonly cited query that aggregates and tabulates the first_time column from the v$log_history view by hour of day, reporting the hour across the page and the date down the page. It often appears in the responses to the question “how big should my online redo log files be?” but I’m not going to supply the query here because it’s irrelevant, instead I’m going to show you a line of the output it produced (on a real production system) then ask the important question that might prompt you decide to resize your log files: