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March 2020

Create a Simple Oracle VM on Azure IaaS

Use the following shell script to create your Oracle VM.  I chose the following parameters to create mine:

Using Azure Cloud Shell and with persistent storage, which are linked on the github page, I uploaded the mk_oravm.sh script and run it after changing the permissions.

chmod 744 mk_oravm.sh

Provision the VM

Run the script:

 ./mk_oravm.sh

Anwser the questions from the script:

Silent installation: Oracle Restart 19c, ASM Filter Driver, RHCK edition

As promised in the earlier post here are my notes about installing Oracle Restart 19c on Oracle Linux 7.7 using the RedHat compatible kernel (RHCK). Please consult the ACFS/ASMFD compatibility matrix, My Oracle Support DocID 1369107.1 for the latest information about ASMFD compatibility with various kernels as well.

Why am I starting the series with a seemingly “odd” kernel, at least from the point of view of Oracle Linux? If you try to install the Oracle Restart base release with UEK 5, you get strange error messages back from gridSetup telling you about invalid ASM disks. While that’s probably true, it’s a secondary error. The main cause of the problem is this:

Oracles Free TNS Firewall - VALIDNODE_CHECKING

I said in a post a couple of days ago that my overall plan to secure an Oracle database; actually my plan is to secure the data in an Oracle database not blindly just secure Oracle. We must focus on....[Read More]

Posted by Pete On 31/03/20 At 12:26 PM

Where to add Index on Postgres

 

Summary

Goal in this post is to layout a methodology that can be implemented to scan the explain plans and identify opportunities to optimize the sql execution with additional indexes.

The missing index opportunities outlined here are

  1. Indexes that would avoid full table scan with a predicate filter that filters out most of the returned rows
  2. Joins that are missing index on the join field
  3. Index range scans that could be made more efficient by addition of a field to existing index

Also for future consideration, but not yet outline here

Add A SQL*Net Security Banner And Audit Notice

I would have to say whilst I see security banners on customers Unix boxes when I am allowed to log in as part of a security audit I canot ever remember seeing a security banner when I log into a....[Read More]

Posted by Pete On 30/03/20 At 02:02 PM

Combinations and consequences

Fellow Perth techie Scott Wesley sent me this interesting puzzle recently. He was using the long awaited feature of being (finally) able to assign a sequence value via the DEFAULT clause in a table definition.

The problem was … the sequence was NOT being assigned. And since that column was defined as NOT NULL, his application was breaking. We had some to-and-fro and finally I managed to reduce it down a very small test case, which I’ll build from scratch here.

Oracle 19c Automatic Indexing: Index Created But Not Actually Used (Because Your Young)

    The following is an interesting example of how Oracle Automatic Indexing is currently implemented that can result in an Automatic Index being created but ultimately ignored by the CBO. To illustrate, we begin by creating a simple little table that has two columns of particular interest, CODE2 which has 100 distinct values and […]

Oracle recovery concepts

I’ve published a while ago a twitter thead on some Oracle recovery concepts. For those who are not following twitter, I’m putting the whole thread here:
 

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Locating Oracle Enterprise Linux Images for Azure

Just like with other UI’s, the Azure portal may not show you the wealth of offerings that can be found in the Azure catalog.  For those Oracle DBAs hoping to build an IaaS VM image from a certified OS version, this means they need Oracle Enterprise Linux and are frustrated when they can’t locate it in the portal.

Empower with the Cloud Shell

Oracle DBAs rarely are fascinated with user interfaces or portals, so when you offer us something like the Azure Cloud Shell, it’s something we should embrace.  I’ve spoke about it before and I will rave about it again here.  If you haven’t set it up, skip the download to your desktop and simply go to Azure Cloud Shell and connect to your Azure account.  Once there, ensure you’ve set the CLI to BASH and use this just as you would Putty or Xterminal.

ORA-28050 - Can I drop the SYSTEM User?

Two things most annoy me with the Oracle database in terms of securing it and this is the abundance of default users in most Oracle databases that I perform security audits on and also the massive amount of PUBLIC grants....[Read More]

Posted by Pete On 27/03/20 At 06:11 PM