Kurt Van Meerbeeck

Expert Oracle Practices

kurtvm — Fri, 29 Jan 2010 11:08:07 +0100

I was just woken up by the mailman, ringing my doorbell several times.

I jumped out of bed and opened the door half naked and still sleep drunk - I was on call this week and although there weren't many calls I went to bed at 2AM, each day. If there's one thing I hate is going to bed and getting a call an hour later - so I go to bed late at night and hope I don't get a call until 8AM when a colleague takes over.

Anyway, I knew it was the postman delivering the new Oaktable book 'Expert Oracle Practices'.

Because I had bought it at Amazon in the US, I knew I had to pay import taxes (10euro) and thus needed personal delivery. Hey, I wanted to have it asap

This is one of those books you just need to have !

I've already mentioned here that I love going to the UKOUG - and one of the main reasons is because I love to hear how other DBA's/developers do their work. How do they backup their databases, how do they tune their databases, what problems are they having.

The new Oaktable book is very much like that - how do some of the most respected database consultants handle their environments. It's not a low, lower, loooower, Steve Adams low level book. But at first glance it looks more technical than the first Oaktable book (Oracle Insights - Tales of the Oaktable)

And that was also the aim - competing with the other new Oracle 11g books out there.

I'm ashamed to admit that I turned down an offer to write a chapter (even two chapters). I was offered a chapter on backup and recovery and one on NLS issues.

The first one is obvious as I have some experiences with recovery - and I could have written some funny anecdotes and picked out some cases that went bad and why.

But the aim wasn't to write funny stories but technical content.

I have a confession to make - I hate writing technical content/documentation - but I love programming.

If you want to punish me - get me to write technical docs. One of the reasons I quit my previous job was because at one point, they had me writing more technical docs to be ISO9000/1/2 compliant than actually programming stuff. I don't know why I agreed on 2 chapters but with the words of a famous entrepreneur 'screw it, let's do it', I set myself a goal :

try to write 10% of one chapter in one week

Mind you this was the beginning of the summer, the worst possible timing for me, as I had filled up most of the summer weekends with other things to do.

For the backup and recovery chapter, I already had some ideas on how to handle the chapter - I wanted to do a bottom up approach.

Most books do a top down approach - they explain the concept, the wider picture, go to the commands and then some examples, and maybe some internals.

I seem to always learn things bottom up - start with the internals and then work my way up to the commands. It's like a bottom up and top down parser . If you understand the internals, the mechanics, you know what you're doing and thus, don't need to memorize all the commands ... you just need to understand to know what's possible!

Anyway the idea was to first explain block internals, how data is stored and how redo logging works, using a chessboard.

Let's say 2 guys are playing 10 chess games on 10 boards at the same time in the outdoors. They each move pieces, the movement of the pieces get logged by a third person on a piece of paper and once in a while a 4th guy writes down the location of every chess piece on each board to another piece of paper.

The 2 guys playing the chess games are database processes changing rowpieces (chess pieces) in the datablocks (chess board) - the guy writing down the movement of the pieces (redo vectors) is the logwriter process. They guy writing down the complete chessboards to paper is the dbwr process. If it starts to rain, they just scrap the boards (shutdown abort). When they start playing again, they get the paper containing the complete chessboard layouts and the paper with the chess piece movements and redo the movements (instance recovery). It is basic journaling !

With this story in mind I could have explained backup and recovery in a very simple way so everybody understands, and then move my way up.

Anyways - after a week of writing in the evenings I had one page ! One page and I was so bored !!! I'm definitely not a technical writer … a blog now and then…ok. A presentation once a year … fine. But 2 chapters in a book … I don't think so.

So I got back to Jonathan Gennick after a week - I didn't make my goal - I could not see, with the deadlines in place, how I could find time (I have 2 jobs and need to sleep now and then) to write those two chapters and I thought it would be best to let him know before I signed a contract. And you know what, I have not regret it since !

Btw - about the second chapter, NLS issues - I live in Belgium. We have 3 official languages : Dutch, French and German. And we use English to keep everybody happy. So we know allllll about NLS issues

Now - go buy this book - it's awesome !

On a different note …. I do have more time in the winter season and I was able to qualify for the Flemish Poker championship or 'Pokerkampioen Van Vlaanderen'. It's a freeze-out tournament covered by TV. It will be aired on March on 2BE and JimTV. There were 674 entries for the regional finals. I made it through the semi finals and busted out on place 28. I wrote about it here. It's all non-technical content !

UKOUG2009 - I too can blog about it ...

kurtvm — Thu, 03 Dec 2009 15:24:27 +0100

I don't know how they do it !

When I go to a conference, I make an agenda and mostly follow it all the way through - I might make a few changes here or there, but I won’t easily skip a slot… unless an emergency comes up … which happened only twice in these 3 days

That brings me to my first observation of UKOUG2009 … wifi sucked !!!

When I go to a conference I still need to be available – I *need*wifi access to survive. I only was able to get the ICC wifi to work during the parties!

The mickey mouse portables available at the exibition hall and registration area didn’t do me any good either – I couldn’t ssh out of them !

Luckily I found some unprotected wifi signals in the exhibition area – my gratitude goes out to the people who had setup the NETGEAR wifi appliance – you delivered excellent internet services although I reckon this was unintentionally as it was protected the last day of the conference

Here ‘s a way to get people to come to your booth – if you have wifi – name the network to your company, and give people the password if they visit you – success guaranteed !

Anyway – I got deferred – I was wondering how people do it –blogging and twittering during a conference while there is so much to do, so much to see, so much to process. And I reckon, a lot of people were twitteringand blogging … that probably was the cause for the bad wifi !!!

So I decided to blog a bit about UKOUG2009 when I got home.

We arrived on Sunday at Jurys Inn – which is about the best hotel you can get without going to the Hyatt. Every year I seem to bring mor eand more people of the company with me – this year our company had sent 9 people ! The hotel looked a bit quiet so we decided to head to All-bar-one.Which again looked a bit deserted … it seems the credit crunch had taken it’s toll here !

So what about the sessions – I have a broad interest – the last couple of years I do more and more application server stuff, networking, identity management and programming than hardcore DBA work.

I had sessions on my agenda ranging from ‘Getting the best out of hardware loadbalancers’ to ‘Integrating forms with apex’ over ‘Authentication,SSO and authorization for WLS’ and Tanel’s ‘Latches and mutexes’ talk. And they say I am a database geek – I reckon I attend more talks on middleware thandatabases.

Now for those of you moaning about how bad some presentations were and how you could do so much better – go out there and do it. Write a apresentation and/or whitepaper and get your butt out there.

One of my colleagues attended a talk on ADF 11g by someonefrom Oracle – afterwards they had a chat and in between my colleague mentions how his team had created a kick ass app in ADF 11g. In which he got the reply ‘well– show it to me’ ! End result – if he writes a paper about it, he may present it at Oracle Openworld 2010!

So what about the sessions I attended – here are some highlights :

Alex Keh’s talk on Active Directory and Windows Security integration with Oracle databases – Alex presentation was great – excellent topic, good presentation style, working demos and I learned a couple of new things.

Joel Goodman from Oracle education had a strange presentation title – something about DB Links PART 2. I couldn’t find part 1 in the agenda. Apparently he had submitted 2 presentations but part 1 didn’t get accepted. Nonetheless – Joel Goodman knows his stuff – he also reminds me of Wolverine – deep voice, American accent … it’s almost as if he tries to hypnotize you while pumping valuable knowledge into your brain. (I wouldn’t mind having him around in a street fight ;-) ) This presentation was all about distributed transactions and how crashing databases, involved in distributed transaction,can lock complete tables until you force commit or force rollback the transactions. I had completely forgotten about that. The last time I had to do something like that was in the Oracle7 era. So 2 thumbs up ! Joel puts hispresentations free for downloading here: http://dbatrain.wordpress.com/articles-papers-and-presentations

Joel’s partner in crime Harald Van Breederode, and equally excellent presenter talked about 11g SQL Plan Management. This is something I get confronted with quite a lot – plan stability. Don’t you hate it when a new execution plan just hogs down a complete database. In my opinion, Oracle should have introduced SQL Plan Management when they introduced the CBO ! The one can’t live without the other and yet it has taken over a decade to get this feature –my guess is it was just too resource hungry for the hardware available back in the days. I love to quote Hannibal Smith on this : ‘I love it when a plan comes together!’ Harald hasn’t posted his presentation on his blog – but who knows, one day he might!

I’m a java guy but that doesn’t mean I can’t appreciate plsql – I like it better then say … perl – so I went to see Steven Feuerstein’s‘High Performance PL/SQL’ – very interesting stuff. He spent quite some time on ways to cache data in the pga/uga using all sorts of tricks, ending up with 11g’s result cache. Not too bad I thought – but Connor McDonald showed a little bit more skepticisms on the result cache. He proofed that if the result cache isbeing populated and concurrent sessions are running the same query which ispopulating the cache, extra locking occurs. As usual, Connor delivered one of the best, well probably most definitely *the* best presentation of UKOUG2009 inhis usual style, firing away *485* slides in 45 minutes !

I went to quite a lot of weblogic/ias presentations. It looks like people that are Oracle acquired from the acquisitions haven’t the slightest idea of what Oracle Portal/Forms/Reports are, and *how many* people are still using it. Every presentation was heavily (not heavenly) focused on java functionality, with Forms/reports dangling, almost falling of the slides ! One guy was quite hilarious – it was a talk about SSO and WLS … to be honest I was expecting something about how ‘legacy’ apps like Oracle Forms/reports/portal and Oracle SSO (OC4J_Security) would integrate with the new Weblogic App server. Instead it was a talk about Oracle’s Identity & Access Management suite build on top of WLS. No biggy – quite interesting especially from someone who co-wrote the SAML standards.

But what I suspected would happen, did happen … someone asked a question about how all this would integrate with Oracle Portal if they migrate from IAS 10.1.2.3 to Weblogic ……………….

This was going to be good as I was also interested in that. The answer was way off, it was quite clear he had no idea what Oracle Portal was or how it is deeply integrate with PLSQL (and the PLSQL SSO api) and OID. The person who asked the question tried to reframe the question but again … no serious answer –‘no, but in java … blah blah blah’ … you could see the disappointment as the person who asked the question politely nodded along and thanked the presenter for this very straightforward answer.

This confirms to me that Portal is *dead*. If you run a public website on Portal – get drupal. It’s cheap, it has way better SEO and thrives on a very large community. Oh – and I have created a drupal module that integrates drupal user management with Oracle SSO. Throw away Portal – it’s a real pain to migrate upwards (I’m stuck at Portal 10.1.2.3 as I’m unable to migrate to 10.1.4.2 even after a 2 week SR with Oracle). Throw it out… you’ll feel much better and people will like you for it

One other hilarious moment was Julian Dyke’s presentation on 11gR2 new features. Julian makes excellent presentation/slides/animations. So for that reason alone, if I can, I tend to go to any of his talks. However, at the beginning of his presentation, he mentioned he had forgotten a word in his title : ‘RAC’ – ‘11gR2 *RAC* new features’. This resulted in quite a lot of people leaving the room. I decided to stay purely based on Julian’s reputation.However, I had to leave afterwards when I got an important phone call …(damn wifi) and I was glad I had an excuse to leave the room. I took the 11g RAC course in February of this year. When Julian started to talk about all the new RAC stuff like SCAN, I felt depressed. It was like I could throw away half thet hings I had learned in the course – ‘this is new, that’s new, that’s changed,this is obsolete, this works like that now …’ … too depressing …

To end this post – here’s a picture of a collegue of mine at the Fire & Ice Party (disclaimer – the girl had already left – she’s not under the table)

I need to lay down now after another great UKOUG conference .... till next year !!!!

Cloud computing - my server is out there man !

kurtvm — Mon, 16 Nov 2009 10:16:27 +0100

Price is non-negotiable

This website is hosted on one of my servers co-located at a data centre near Brussels. It's a DELL Poweredge 850E with 340W powersupply.

I use my own dedicated server because I *sometimes* need large amount of storage. For example, if a customer has a crashed database and wants to upload his datafiles. We're speaking 100Gb or more.

So I need large amounts of storage - not all the time - and bandwidth. The server is hooked up to a 100Mbit internet backbone so I got that one covered too !

A couple of years ago, my only option was to buy a physical server, find a hosting company that offers co-location and hire 1U rackspace.

Cloud computing has changed this game - that and the price of electricity at datacenters.

Two months ago I was thinking of buying a server to replace the old DELL server - it was 3y old and I wanted bigger disks

Coincidentally, when I had configured a new 1U box on DELL's website, I got a call from my hosting company.

After hearing a whole story about how they got new racks (more current, better cooling, bla bla bla) and that I had to migrate my server, they dropped the bombshell on pricing.

Electricity prices had gone up and they had to re-negotiate prices with the datacenter.

Much to my surprise, the new price was three times the current price. Now I don't know about you - but if you have to pay 3x the price for getting the same service, something is wrong (did I mention that the year before they also upped their price with 20%)

Suddenly a power supply of 340W became extremely expensive. Did you ever had a look at those 200W servers … I'd rather run a business on a laptop than on one of those mickey-mouse servers… at least my old DELL has hardware raid and a decent cpu...

So - either they were lousy negotiators - or they wanted their customers to pay for their new - probably golden - racks.

It was a lousy sales-pitch too - the sales guy offered me to think about it and check out the competition … which were all cheaper than them ;-)

Anyway - prices were non-negotiable - so I first checked out several competitors in the same and other datacenters.

Now with co-location - all you get is rackspace, current and network. That's it.

One hosting provider's current is not better than another's - so the only criteria are price and maybe the datacenter's reputation. (well ok - there are minor differences regarding network limits, but co-location is basically easy money for providers).

So there I was - comparing prices of different providers at different datacenters. And as price and network was my only criteria I chose to move to a small provider at the Scarlet datacenter in Vilvoorde. It's a really small and young provider/company as they only have 2 racks there (and 2 racks at another datacenter).

Now, I didn't want any downtime - that meant renting computing power, temporarely migrating the website and all programs that allow for the generating DUDE licenses (which is a bit more complicated that running some 'make' or 'ant' scripts), switching DNS, while doing the physical transfer of the server.

The Anjo connection

I remembered one time I was at Anjo Kolk's place. I had bought 2 second hand Sun servers from him. He had bought 40 of them in the US and had shipped them to The Netherlands, so he could spare a server or two

Anyway - I told him I was going to use the servers for a new project of mine, where I needed a linux cluster for running my own DNS servers. At which point he started demonstrating Amazon EC2 and how I could use cloud computing to do what I wanted to do, without the hassles of hiring extra rackspace or getting a NAS for storage.

I must say I was intrigued … but it all looked a bit fragile and over-complicated.

I mean, I just wanted some cpu, some storage and network.

With Amazon I had to choose from an aws image in the EC2 cloud - then, if I wanted persistent storage, I had to rent Amazon S3 storage. Huh persistent storage ?

It looks like Amazon's VM's are snapshots from common images and if you shutdown your VM or your VM crashes, the VM reverts to the original image, losing all your changes… unless you backed it up to your persistent S3 storage … which couldn't be mounted as a file systems but had to accessed through HTTP protocols … huh???

I just want disk space … how hard is that ?

Anyway - because of migration and uptime issues I was facing, I took a new look at Amazon EC2 and it seems they finally have mountable persistent storage, which they call Amazon EBS (or elastic block device) or what I like to call - a disk.

Still, if your VM crashes, you lose your configuration unless you back it up to your EBS or somewhere else and reconfigure after the crash (someone correct me if I'm wrong).

That's OK as I only needed a VM for a day or 2, while my own server was physically being moved to the new datacenter. So I signed up for the Amazon EC2 service. And then I waited … and waited…. It took them 2 days to activate my account… too slow.

Amazon and goliath

While I was waiting for my account activation at Amazon, I decided to look at other cloud providers … there is only a handful and most of them are based on virtualization software like VMware, Xen and KVM. The downside is that they all offer fixed configurations like :

Small config : 1 cpu core, 1Gb mem, 20Gb disk
Medium config : 2 cpu cure, 2Gb mem, 40Gb disk
Large …. You get the idea

In my opinion - cloud computing should provide flexible configurations at flexible prices.

This was only cloud computing in the sense that you pay by the hour but it's not as flexible as Amazon that you can say - I want 1 cpu core, 1Gb of memory and 200Gb of disk.

Nooo, if you wanted 200Gb of disk space, you needed to take the *extra large config* with 16 cpu cores, 8Gb memory and that happened to come with 200Gb of disk space and will cost you as much as a half a rack and 4 DELLs if you keep running it for a whole year.

But wait - I've found the one exception, that absolutely lets you choose all 3 (cpu/mem/storage) independently - and they are called Elastichosts.com, a UK based cloud provider.

And what's more - they let you try it out for free for 5 days !

And … they give you a fixed IP address unlike Amazon's elastic IP address which will make you jump to 20 burning loops before you can receive/send mail to/from your server that is not marked as spam.

Elastichosts runs on Linux KVM and they have made sure that all interfaces are very simple - a disk is a disk - an static ip really is a static ip.

No fuzzy acronyms.

In fact, I was reminded of Larry Ellison's opinion of cloud computing … it's just a simple server that is 'out there' - it needs cpu, memory, network and electricity - and for me affordable flexible pricing - that's it !!!

Maybe I'm an idiot but Amazon just took it a step too far and made it too complex !

In case you've misted Larry's interview on cloud computing :

Epilogue

Anjo has been running an Amazon AWS for over a year without crashing.

I migrated the ORA600 server without downtime to the Scarlet datacenter which is located in the same building as the Belgian Oracle office (you've got to love the irony )

A friend of mine who was also co-locating a server at my original provider was offered negotiable prices a couple of weeks later (maybe tripling their prices wasn't the best of ideas). He too migrated to another datacenter.

If a hosting company ever pulls a trick on me again, I'm throwing away my hardware and move to elastichosts.com for good.

Have a look at elastichosts.com - it rocks !!!

ORA600 Aggregator mobile theme

kurtvm — Fri, 09 Oct 2009 09:47:20 +0200

I caved in ... I bought an iPhone.

I still think the price is a total rip-off here in Belgium - and there's a 6 week waiting list.

All because in Belgium force bundling sales are not allowed. This makes the iPhone simlock free but it comes at a price.

Anyway - when I looked at the news aggregator, I thought I could do better and so the aggregator now detects mobile browsers and switches to a mobile theme. The implementation uses an mobile theme, a browser detection (browscap), a themeswitcher and the iWebKit. The implementation was done in 15min all because of the drupal framework . I wonder how long this would take in Apex - or god forbid Portal !

When I started this site, and needed to pick a framework, I was favoring Apex because I knew it already. And I have some experience with Oracle Portal. However, the problem we were having at a customer site with Portal (or apex) and search engine optimisation (SEO), drove me into drupal which does a great job in SEO. It did involve learning php (but I already knew perl really well) and ofcourse the drupal hook api (which is really another way of thinking and programming). But the payoff comes with all free modules that you can find on the internet and build new functionality in a matter of minutes !!!

Oracle Performance Firefighting

kurtvm — Thu, 10 Sep 2009 21:23:58 +0200

I've been - and still am - very busy lately.

However, when I saw Coskan's review of Craig Shallahamer's book, Oracle Performance Firefighting, it reminded me of the fact that I had put this topic on my blog todo list.

But unlike the other topics on my list, I really wanted to get this one out first.

It's been a while since I've been so excited about a book.

Craig is the guy behind Orapub and also the author of Forecasting Oracle Performance.

I'm a bottom-up learner - like bottom-up parsers (as opposed to top-down parsers) I like to get my facts as detailed as possible and then work my way up to more general topics. For example, when I learned my backup & recovery skills, I learned about block internals first as opposed to diving in all sorts of high level commands.

This means I really appriciate books like Steve Adams' Oracle8i internals, James Morle's Scaling Oracle8i or Bach's all time classic Design of the Unix OS.

I think Craig's new book fits right in there.

I found out about the book a couple of months ago as Daniel Fink told me he was reviewing this book - I immediately ordered it on Craig's site before it was available on Amazon.

I must admit, I've only read chapters 6, 7 and 8 - covering buffer cache internals, redo internals and shared pool internals. These are 3 chapters every dba should read !!! Those 3 chapters are worth the price on their own !

So if you're buying only one Oracle book this year - buy this one !!!

And while you're buying books, get Christian Antognini's Troubleshooting Oracle Performance too !

PS - for the fans of Oracle Insights - tales of the Oaktable - TOTOT2 is on it's way !