Plan Shapes

There are a number of articles, webinars, and blogs online about how to read execution plans, but many of them seem to stop after the the minimum description of the simplest type of plan, so I thought I’d throw out a brief comment on a couple the slightly more complicated things that are likely to appear fairly commonly because you sometimes find plans with very similar shapes but extremely different interpretation.

First: select with scalar (more...)

Automatic Deployment of CDBs with non-default database options in 12.1.0.2

I have written about the importance of automation in previous posts, and this one is following the same line. This time I wanted to test and document my experience with “golden database templates”. Wy? Because most DBAs will appreciate that there are more interesting things to do than to run “create database” scripts all day, so why not automate the process? For quite some time DBCA, or the Database Creation Assistant offers you the option (more...)

Next Round Of ANZ “Let’s Talk Database” Events (July/August 2016)

I’ll be presenting the next round of “Let’s Talk Database” events around Australia and NZ this winter in July/August 2016. These are free events but due to limited places have often “sold out” in the past, so booking early is recommended to avoid disappointment. All events run between 9:00am – 12:30pm and are followed by a networking lunch. We always have […]

Real-time visualisation of Hadoop resources

At CERN we run multiple Hadoop clusters to satisfy demanding requirements from our experiments and accelerator communities. The usage and criticality of the clusters are increasing dramatically as more users are looking at Hadoop to process and archive the vast amounts of data coming out of LHC.

Streams rules! OK?



Continuing my love hate relationship with streams - today presented another interesting challenge when this email alert from cloud control appeared in my inbox



So ORA-4080- pretty unusual error (well not the normal kinds of failures anyway) - what is that?

 oerr ora 4080
04080, 00000, "trigger '%s' does not exist"
// *Cause:  The TRIGGER name is invalid.
// *Action: Check the trigger name.

OK sounds simple enough - so whats gone wrong?

Lets drill (more...)

Private Life – When the Pond Came Inside

It's not deep - but it's still unwanted!

It’s not deep – but it’s still unwanted!

This week my plans were thrown into chaos when our house flooded. Before I go any further I should state that everyone is fine, no structural damage was done and we were about as lightly flooded as you can be whilst still being, well, in the situation of having dirty, contaminated water in your home. Let’s just say our garden pond partially relocated into our house but (more...)

VirtualBox 5.0.22 Released

VirtualBox 5.0.22 has been released.

The downloads and changelog are in the usual places.

Judging by the progress of 5.1, now in beta 3, it won’t be long before we’ve got something new to play with. 🙂

Cheers

Tim…


VirtualBox 5.0.22 Released was first posted on June 17, 2016 at 2:02 pm.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. If (more...)

Cardinality trick

In the absence of a virtual column or function-based index, the optimizer uses a basic selectivity guess of 1% for a predicate of the form: “function(column) = constant”; but there is (at least) one special case where it gets clever; simple type conversion:


create table t1 nologging
as
select  cast(
                case
                        when mod(rownum,1000) = 0 then 0
                        when mod(rownum,100)  = 0 then 1
                                                  else 9
                end as varchar2(1)
        ) v1
from
        all_objects
where   rownum  (more...)

LOGGING and temporary space

We had an interesting question on AskTom this week.  The poster had been told by their DBA that the reason their large INSERT-AS_SELECT statement was consuming lots of temporary segment space, was because the database had been recently altered to enable FORCE LOGGING, presumably to ensure easier consistency in a physical standby node.

So … here’s a simple test case to demonstrate that this assertion is wrong.

First we build up table, and then (more...)

Graph frequently executed SQL by FORCE_MATCHING_SIGNATURE

I made a new graph in my PythonDBAGraphs program. Here is an example with real data but the database name blanked out:

sql_matching_group_of_signatures_blog

My graphs are all sized for 1920 x 1080 monitors so I can see all the detail in the lines using my entire screen. The idea for this graph is to show how the performance of the queries that matter to the users changes as we add more load and data to this (more...)

How To Avoid Exadata Cell Node Reboot While Modifying NTP Service

Recently, we had a hardware failure on our NTP server which caused its crash. Due to this, the ntpd daemon on compute nodes and cell nodes went offline. After fixing the hardware issue on NTP server, starting ntpd service using "service ntpd start" on compute nodes was successful but when I started the ntp service…

Intro to Database Security – Part 3

In the previous parts I talked about introduction to the security world and database security. In this post I will dive into the infrastructure aspect of the database. Links to the previous posts: Part 1 – general introduction to security Part 2 – introduction to database security As I wrote in the first post, we […]

Joining Delphix and Not Fearing Hot Coals

Back in 2012, when I started to build a reputation as a mentor, the goal was not just to create my own path and set it afire, but for others to desire to make their own path before my footsteps cooled.

hot-coals

Never Fear Hot Coals

This week I joined Delphix.  Many acted as if this was pre-ordained and simply part of my destiny.  Due to my technical knowledge, they assumed (more...)

KeePass 2.34

I’m a little late to the party, but I just noticed KeePass 2.34 was released a couple of days ago. You can download it here.

You can read about how I use KeePass and KeePassX2 on my Mac, Windows and Android devices here.

Cheers

Tim…


KeePass 2.34 was first posted on June 15, 2016 at 11:13 am.
©2012 "The ORACLE-BASE Blog". Use of this feed is for personal non-commercial use only. (more...)

Advertising

Someone approached me at a recent conference to ask if I was available for hire and, in the course of the conversation, pointed out that he hadn’t really been certain whether or not it was possible to hire me for consultancy work. This made me realise that I don’t advertise very much, I usually forget to remind people that I can be hired, and I hardly ever remember to hand out (or even have available) (more...)

“It Doesn’t Work”


“Since you got here by not thinking, it seems reasonable to expect that, in order to get out, you must start thinking.”
— Norton Juster, The Phantom Tollbooth

The Devil is in the details, however, in support forums and newsgroups, the Devil is just as present when the details are either sketchy or non-existent. Volunteers in such forums and newsgroups quite often hear the dreaded words “it doesn’t work”, followed by … nothing. No (more...)

SELinux blocked my .Xauthority

I was attempting to install an OEM management server on a new host in the lab using runInstaller.  Of course the installer is an X-windows app so I need to configure port forwarding to get the display back to MacBook.

I added the new host and its bastion to my ~/.ssh/config file to set up port forwarding:

Host 10.123.45.678
ConnectTimeout 60
StrictHostKeyChecking ask
ProxyCommand none
UserKnownHostsFile ~/.ssh/known_Hosts
User oracle

Host newlaboms. (more...)

clckwrk Design Blueprint: Peoplesoft Campus Solutions on AWS

Higher eduction establishments around the world use Peoplesoft Campus Solutions from Oracle to manage their key business processes. 

In this reference architecture we look at the key requirements for Campus Solutions and the technical solutions that can be deployed on the Amazon Web Services Cloud. 




Availability: Campus solutions needs a high availability infrastructure to ensure that both the administrative and student users can access data at all times. This solution uses multiple web and (more...)

Oracle Support Frustration

If you remember, after the last OOW I was very impressed by the Oracle Support people I met there. They were very knowledgeable and willing to help and solve problems. But now I remember why people are frustrated with Oracle Support… Over a month ago I tried to restore a database backup from S3 (I’m […]

Using OSWatcher for system diagnostics

OSWatcher is a superb tool that gathers information about your system in the background and stores it in an (optionally compressed) archive directory. As an Oracle DBA I like the analogy with statspack: you make the tool available on the host in a location with – very important – enough available disk space and then start it. Most users add it to the startup mechanism their O/S uses- SysV init, upstart, or systemd for example (more...)