AWS CloudWatch with Delphix AWS Trial

I love valuable metric data and I wanted to see what’s offered from different cloud providers.  Metrics are data and data ensures that when performance is impacted, we have the information we need to answer questions and resolve issues.

For my first adventure, we’ll start with a high level review of Amazon.  Cloudwatch is one of the main tools to inspect the workload on instances in (more...)

ORA-54002 when trying to create Virtual Column using REGEXP_REPLACE on Oracle 12cR2

I encountered an issue today trying to create a table in an Oracle 12cR2 database, the DDL for which, I extracted from an Oracle 11gR2 database. The error returned when trying to create the table was:

ORA-54002: only pure functions can be specified in a virtual column expression

The definition of the table included a Virtual Column which used a REGEXP_REPLACE call to derive a value from another column on the table.

Here is a simplified (more...)

Business rules, common sense and query performance

Very often, significant performance benefits can be obtained by using some very basic knowledge of the application, its data and business rules. Sometimes even less than that: even if you are not familiar with the application logic at all, you can still use common sense to make some reasonable guesses that would get you a long way in improving query’s performance. Here is an example (based on an actual query that I had to tune (more...)

VirtualBox 5.1.18

It’s barely a week since 5.1.16 dropped and here we have VirtualBox 5.1.18! 🙂

Downloads and changelog are in the usual places.

I’ve done the installation on my Windows 7 desktop at work. I’ll do the updates of the Mac and Oracle Linux 6 hosts over the weekend probably.



VirtualBox 5.1.18 was first posted on March 16, 2017 at 2:58 pm.
©2012 "The ORACLE-BASE Blog". Use (more...)

Problem with V$RECOVERY_AREA_USAGE view and FRA space not being reclaimed

We received the following alert from our alerting system
Flash Recovery Area for FOLPRD1A has 9.97 percent of usable space left.
This is a standby database:
HOST       INSTANCE   STATUS     VERSION      STARTED                   UPTIME
———- ———- ———- ———— ————————- ————————————————–
xxxxxxxx   INSTANCE   MOUNTED   18-JAN-2017 18:58:18     (more...)

Getting Started with GoldenGate

Not a blog post, but a link to my article in the UKOUG quarterly magazine OracleScene – great publication with some fab articles.


Filed under: Administration

Let’s Talk Database: New Dates Released (You Can’t Talk)

Good news for all you Oracle Database folk in ANZ. I’ll be running a new series of “Let’s Talk Database” sessions at a venue near you in the coming months. I’ll be discussing two interesting topics, “Introduction to the Oracle Cloud for DBAs” and “Introduction to Oracle Database 12c Release 2“. The dates for this series and […]

Let’s Encrypt : Free Certificates on Oracle Linux (CertBot)

My website has been using HTTPS for over 18 months now. A couple of months ago I came across Let’s Encrypt and thought, “Free Certificates? That’s interesting!”, so I gave it a shot for some other stuff I look after, just to see how I got on with it.

The certificates only last 3 months, but you can automate their renewal using CertBot. You set it up to check every day, and the certificates get renewed (more...)

Starting an instance with sqlplus and running into ORA-27302: failure occurred at: skgpwinit6

Recently I was applying the data dictionary part from an (exadata bundle) patch and ran into the following errors:

ORA-24324: service handle not initialized
ORA-24323: value not allowed
ORA-27140: attach to post/wait facility failed
ORA-27300: OS system dependent operation:invalid_egid failed with status: 1
ORA-27301: OS failure message: Operation not permitted
ORA-27302: failure occurred at: skgpwinit6
ORA-27303: additional information: startup egid = 1001 (oinstall), current egid = 1002 (dba)

This was very weird, I had just (more...)

Online Table Moves and Partitioning in Oracle Database 12c Release 2 (12.2)

A couple of articles have crept out over the last few days that relate to online operations on Oracle Database 12c Release 2 (12.2). Both of them are pretty small in terms of what you have to do, but are pretty awesome in terms of impact, so I’m giving them the official thumbs-up! 🙂

The first one is about moving tables online.

I (more...)

12.2 Moving Tables Online (Real Cool World)

One of the really cool new features introduced in Oracle Database 12c Release 2 is the capability to MOVE tables ONLINE, while maintaining all the associated index structures. This was possible for table partitions in Oracle Database 12c Release 1 but only for Indexed Organized Tables before then. Rather than show a demo that just moves a table, […]

12c Release 2, set feedback enhancement in SQL PLus

There’s a nice little touch to the “set feedback” command in SQL PLus in 12.2. There is a new “only” clause in the SET FEEDBACK command, so you can run queries but the resulting rows are not shown in the display. They are still queried, fetched and “returned”, but just rendered to the screen. Here’s an example

$ sqlplus hr/hr

SQL*Plus: Release Production on Tue Mar 14 22:59:15 2017


Pi Day, March 14

Geeks around the world will be celebrating Pi day, a shameless excuse to put the month before the day like the Americans do so we can talk Mathematics on “3.14” day Smile

So what better way to show how cool SQL can be with some expressions to approach Pi with continuous series

All we really need to know by way of background is the CONNECT BY LEVEL trick to generate arbirtary sequences of row, eg

Reducing fetch time

Database query tuning is mostly about getting better plans. Mostly, but not always. Sometimes, the problem has nothing to do with the plan, and you might need to get a bit creative to find a solution. In this recent case a query was showing a decent performance when running from SQL Developer, but it took about 5 times longer to complete when running from R. The plan was the same, so I knew that it (more...)

Israelis in the Wide World

I ran into this post on Linkedin talking about what non-Israeli people should expect when working with Israelis (and especially if they visit Israel for business). It’s a very nice read and it’s not long. After reading it (and laughing to myself, as it’s quite accurate), I decided to write this post. Most of the … Continue reading Israelis in the Wide World

12cR1 RMAN Restore/Duplicate from ASM to Non ASM takes a longer time waiting for the ASMB process

Yet another exciting journey with Oracle bugs and challenges. Here is the story for you.

One of our recent successful migrations was a single instance Oracle EBS 12cR1 database to Oracle Super Cluster M7 as a RAC database with 2 instances on the same DB version ( Subsequently, the customer wants to run through EBS cloning and set up an Oracle active data guard configuration.

The target systems are not Super Cluster. (more...)

Little things worth knowing: Executing RDA on RAC

Result! I have finally been able to gather a complete RDA (Oracle Remote Diagnostic Agent) output on my 2 node RAC system. After consulting the relevant documentation on MOS-which is spread over at least 42 Doc IDs-I found them not to be very helpful to the degree that some of what I read is actually wrong or contradicting. I put together a short note, primarily to myself, to remind me of the process. I hope you find it useful, (more...)

Remove OEM 13c Management Repository


Removing the SYSMAN schema and other OEM-related objects from a database consisted of disabling constraints and running a series of DDL scripts in earlier versions of OEM.  Always use RepManager to perform this cleanup for OEM 13c.

RepManager ‘-drop’ command drops the SYSMAN, SYSMAN_MDS, SYSMAN_OPSS, SYSMAN_RO, and SYSMAN_BIPLATFORM schemas and removes their artifacts, including tablespaces and datafiles.


Note:  The following run-time example has been simplified from actual stdout and uses a reference to $MW_HOME (more...)

It’s Private

“The only thing you can do easily is be wrong, and that's hardly worth the effort.” 
― Norton Juster, The Phantom Tollbooth

Oracle provides two parameters that affect the PGA that look very similar but operate very differently. One of these parameters is the well-known pga_max_size and the otheris a hidden parameter, _pga_max_size. Let’s look at both and see how one can be very effective while the other can create problems with respect to (more...)

Swingbench with the AWS Trial

Swingbench is a one of the best choices for easy loads on a database.  I wanted to use it against the SH sample schema I loaded into my Oracle Source database and I haven’t used Swingbench outside of the command line quite a while back, (my databases seem to always come with a load on them!)  so it was time to update my Swingbench skills and catch (more...)