NoCOUG Journal – Ask the Oracle ACEs – Why is my database slow?

Dave Abercrombie mailed me earlier that the May 2011 NoCOUG Journal is already out and can be viewed online at

I met Dave at Hotsos 2011 when he attended my presentation.. apparently we have the same interest about Statistics, Linear Regression, AWR, AAS and he’s got awesome blogs about it at Also being the Journal Editor at Northern California Oracle Users’s Group, he invited me to write a short article about the question:

Why is my database slow?

The NoCOUG Journal having a very wide readership with the last issue being downloaded around 6000 times from (more...)

Oracle by Example portal now shows 12g

A quick post… which is a bit interesting…

As I was searching for Exadata viewlets in Oracle By Example portal ( I clicked on the “Advanced Search”

and then filtered by Product Family (Database) and then by Product

to my surprise there was an option for “Database 12g”….

oh well.. I checked on the Lifetime Support Policy ( and looking at the release dates
it could be possible that they will release the new version anytime this year..

could be in Oracle Open World 2011? hmmm… ;)



Hotsos 2011 – Mining the AWR Repository for Capacity Planning, Visualization, and other Real World Stuff

For all that loves Oracle performance.. Hotsos is truly the best conference, all the speakers are performance geeks, all the attendees talks about performance. Everything is about performance! There are lot more stuff that I like about my first Hotsos experience, the following are some of them..

I like that presenters and attendees are curious about what each performance geek has to say..

I like that whenever their brains are already fried. They consume as much coffee/soda as they can.. and just lay their butts on this couch.. and still.. talk about performance.

I like that after all the sessions, (more...)

Migrating your VMs from VMware to VirtualBox (on a Netbook)

I recently bought a Toshiba nb305-n600 10.1″ netbook with Windows 7 Starter (32bit) on Atom n550, 250GB 5400 rpm disk, & 2GB of physical memory. 

Well this netbook has thrice the battery life (or more) and half the weight of my old laptop ;) so I must say it’s really good for everyday use!

But as a DBA, I would be happier if I can run my VMware VMs on this lightweight lappie!

So coming from a 15″ laptop on Fedora OS, I’ve already installed the tools and all the software I need to be productive on this new (more...)

Wheeew, I am now a RedHat Certified Engineer!

A couple of weeks ago, RedHat announced the general availability of RHEL6… also effective on this release is the change on their certification offering. RHCT will now be replaced by RHCSA (Red Hat Certified System Administrator), and if you would like to be RHCE on RHEL6 regardless of your certification on RHEL5 you still have to go through the RHCSA exam.. and then once you pass.. you are then allowed to take RHCE exam for RHEL6. More details here: RHCSA, RHCE

Since my self study modules/materials are on RHEL5, and it would take a while for the RHEL6 exam (more...)

I’ll be speaking at HOTSOS 2011!

Hotsos is an annual conference that is devoted on Oracle system performance and the people presenting there are really passionate about their research and highly specialized about their subject area. Kinda geeky, but hey, performance is never boring.. and for me there’s still a lot of things to learn on each of the areas of performance and these are as follows: 
  • Application Testing
  • Benchmark
  • Capacity Planning
  • Database Tuning
  • Hardware and OS
  • Performance Tools
  • SQL Tuning
  • Troubleshooting & Internals

Yesterday, I received an email that I have been accepted as a presenter for Hotsos 2011 ;) this is really cool .. !

My presentation (more...)

After OOW, my laptop broke down – data rescue scenario

I just got back in the office from a 2 week conference + vacation (SFO,WAS,NY). Then I was finally back in shape to work and do the usual geek stuff again but suddenly my Neo laptop suddenly stopped working! (the one I mentioned here, but it’s now on Fedora)

It can’t even boot to BIOS, certainly a case worse than BSOD.

So after fiddling with the laptop and systematically ruling out other component failures (power cable,monitor,memory,HD), Yes it’s much like troubleshooting an Oracle database! … we decided to bring it to the service center.

But wait! it may (more...)

Oracle Closed World and Unconference Presentations

There are so many things to blog about these past few days. That is mainly about the cool stuffs around OCW and OOW, sessions that I have attended (OCW, unconference, OOW), plus the interesting people that I’ve met on various areas of expertise.. So I’ll be posting some highlights (and a lot of photos) on the next posts.

Last Monday (Sept. 20) I was able to present at the Oracle Closed World @ Thirsty Bear. The full agenda is here

I did my presentation after Tanel’s live hacking session. There were 30 (+-5) attendees and (more...)

OOW 2010 – the highlights

I started my week with a blast by sky diving at Parachute Center – Sacramento, it was an awesome experience!

Then we went to Redwood Shores to check out the Oracle office

Then headed back to the Moscone area to register and attend the sessions

On the way to the 3rd floor to get the conference materials I saw a familiar face.. yeah it’s my friend Craig Shallahamer! finally we’ve met.. and we had a long talk & catching up about performance related stuff before his talk about troubleshooting “free buffer waits” at 3pm

On the “RAC customer panel” (more...)

OOW 2010 – my schedule

I was able to finalize my schedule a week before the OOW 2010 and most of the sessions that I’ll be attending are related to Performance & Exadata.

So that would be:

You can check my detailed schedule below … (I know it’s a jam-packed sched! I hope I can go to all of them..)

This (more...)

Statistically summarize Oracle Performance data

Here’s the draft of this post , expounded version coming up! :)


We do Guesstimations (calculated or not) once in a while… and this is an interesting read about it…

In the Oracle side… we also use this back-of-the-envelope-calculations for coming up with man-days, capacity planning, hardware recommendations, or just simply knowing what’s happening. And I like these phrases from the article…

“But how can we know the actual figure? We cannot. We can only get closer and closer approximations by measuring things more and more accurately (the volume, not just of the building, but of everything in it, which must be subtracted). It’s not like there’s an (more...)

Graphing the AAS with Perfsheet a la Enterprise Manager

On this previous blog post I was able to take advantage of the AWR repository particularly the DBA_HIST tables to have a far better workload information and nice correlation of the Database Server’s Capacity, Requirements, and Utilization on a single output… and yes… easily going through all the SNAP_IDs!

Having this info made it easier for me to notice trends (text or visualization) and play around with the data (some statistics out of it)… which I can say a big help on finding the root cause of the problem (here and here)

Before going any (more...)

Oracle datafile IO latency – Part 1

On my post about observing the Exadata V1 I had an interesting comment posted by Mark Seger (author of collectl and collectl utilities) about the correlation of activities across a system, the sample and snap time, and seeing the state of the subsystem before and after

The comment made me curious about the effect of snap intervals on the performance numbers of the datafiles and block devices.. especially on the latency numbers.. so I made a few test cases and created some scripts that would give me 5 seconds, 10 minutes, and 60 minutes output of (more...)

The “Not a Problem” Problem and other related stuff

It’s been a while since I visited the Sun Video RSS feed and I found some interesting videos related to performance that are worth sharing and something you could watch over a big cup of coffee..

First is titled Performance: The “Not a Problem” Problem which I could also relate when doing performance analysis for example…

  • When a client instantly jump into conclusion that the performance degradation is caused by the database link well in reality when everything is measured/profiled it turned out that it’s because of the slow IO subsystem..
  • Or when the Data Guard environment was being blamed (more...)

Oracle Mix – OOW 2010 Suggest-A-Session

I hope it’s not too late. I just finished my Suggest-A-Session on Oracle Mix titled “Mining the Oracle Database AWR repository for Capacity Planning“, this might be of interest to you… below is the abstract:

“New CPUs and storage arrays, they are getting faster but these resources are finite and come at a cost. Hence, capacity planning plays a very important role to ensure proper resources are available to handle expected and unexpected workloads. Another critical matter for the DBAs and IT managers is justifying the expense of adding resources on the system. With guesswork you’ll end up (more...)

Seeing Exadata in action

Last week I was able to attend a 3 day exadata workshop conducted by performance engineers from Singapore. It was supposed to be a 5 day workshop with hands on labs but everything was squeezed (unfortunately no hands on) and just the critical sections were tackled.. The workshop highlight was the demos and these are as follows:

- loading large amount of data from an external table
- cell offloading on a typical datawarehouse query
- creation of a 400gb tablespace
- linear scalability of storage cells

Although all of these demos were done on Exadata Version (more...)

My Personal Wiki –

Our brain does not work in a linear or list-like manner (yeah.. not like the guy on the right). From the textbooks and blogs that we read everyday we are all aware that print is laid out in a series of lines or rows…

but our brain is multidimensional…

the information as it is being absorbed could be travelling sequentially to our brain, but internally it is not being serviced in simple lists and lines. There is a complex process of sorting and selecting and the whole network of words and ideas are being juggled and interlinked in order to (more...)

“Ideas build off ideas”… making use of Social Networking sites


In this post (which has been looong overdue :p ) I’ll show you how you could make use of Social Networking Sites to make knowledge sharing and meeting people more fun. As you can see from the illustration above, I’ve made use of the following sites/services to build a dynamic and multidimensional means of communication:

  • Facebook
  • Twitter
  • FeedBurner RSS
  • FeedBurner Mail Subscription
  • Google Sites
  • LinkedIn

The story behind it…

I am a DBA for 4years+, and started with zero knowledge about Oracle. I joined SQL*Wizard, which has a great training program and exposed me to a lot of difficult (more...)

DEVCON Luzon 2010

I just recently I became a member of the PSIA Tech Council… The company I’m working for is a member of PSIA which makes up 90% of the country’s software sector promoting the growth and global competitiveness of the Philippine software industry, also an active partner of the government and academe in implementing programs that benefit the industry.

The PSIA, PSIA Tech Council, together with the Awesome and Cool sponsors will be having the Luzon leg of DEVCON here in Manila!

Below are the details of this awesome event:

09 February 2010, 4-9pm, SMX Convention Center Function (more...)