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October 2011

The Social Development Database

I’ve always been fascinated by development databases — more so sometimes than huge, heavily utilized production ones. Mainly because I’ve seen how the beginnings of a performance problem, or the start of an elegant solution takes shape within a development database. It’s one of the reasons why I love high levels of visibility through full DDL-auditing within development. I love to SEE what database developers are thinking, and how they are implementing their ideas using specific shapes of data structures.

One of the concepts I’d love to see is a “river of news” panel within development tools to see what is going on within a development database. Some of the good distributed source code control systems do this now.

Here’s a good example of what I mean:

http://github-images.s3.amazonaws.com/blog/2011/mac-screenshots/commits-full.png

Happy Birthday Val…

It’s my mom’s 70th birthday today. Happy birthday Val.

I’m flying to China today, so I’ve set this post to publish automatically while I’m in transit. :)

Cheers

Tim…




Debugging PL/SQL and Java Stored Procedures with JPDA

In 2003 I published a paper entitled Debugging PL/SQL and Java Stored Procedures with JPDA. Its aim was to describe how to debug PL/SQL and Java code deployed into the database with JDeveloper 9i. Two weeks ago a reader of my blog, Pradip Kumar Pathy, contacted me because he tried, without success, to do something similar with JDeveloper 11g, WebLogic 11g and Oracle Database 11g. Unfortunately I was not able to help him. The reason is quite simple, since 2004 I’m an Eclipse user…

Few days later Pradip contacted me again to let me know that, at last, he succeeded. Here you find his notes…

  1. Grant the required privileges
  2. GRANT DEBUG CONNECT SESSION to &&schema_name;
    GRANT DEBUG ANY PROCEDURE TO &&schema_name;

Returning to the Day Job.

Having the Summer off. It’s something that quite a few IT contractors and some consultants say they intend to do…one year. It’s incredibly appealing of course, to take time off from your usual work to do some other things. Asking around, though, it is not something many of us self-employed types who theoretically could do, actually have done. I think it is because, although the theory is nice, the reality is a period not earning a living – and the background worry of “if I take a break, will I be able to step straight back into gainful employment afterwards”?

AIOUG Webcast: Methodical Performance Tuning

A big thank you to all those you attended my session today. I sincerely hope you got something out of it. Here are the scripts I used in the demo. And, here is the slide deck, if you are interested.

Remember, this was just the beginner's session. We will have intermediate and advanced ones in near future. Stay tuned through the AIOUG site.

Counting Triangles Faster

A few weeks back one of the Vertica developers put up a blog post on counting triangles in an undirected graph with reciprocal edges. The author was comparing the size of the data and the elapsed times to run this calculation on Hadoop and Vertica and put up the work on github and encouraged others: “do try this at home.” So I did.

Compression

Vertica draws attention to the fact that their compression brought the size of the 86,220,856 tuples down to 560MB in size, from a flat file size of 1,263,234,543 bytes resulting in around a 2.25X compression ratio. My first task was to load the data and see how Oracle’s Hybrid Columnar Compression would compare. Below is a graph of the sizes.

Volatile Data, Dynamic Sampling And Shared Cursors

For the next couple of weeks I'll be picking up various random notes I've made during the sessions that I've attended at OOW. This particular topic was also a problem discussed recently at one of my clients, so it's certainly worth to be published here.

In one of the optimizer related sessions it was mentioned that for highly volatile data - for example often found in Global Temporary Tables (GTT) - it's recommended to use Dynamic Sampling rather than attempting to gather statistics. In particular for GTTs gathering statistics is problematic because the statistics are used globally and shared across all sessions. But GTTs could have a completely different data volume and distribution per session so sharing the statistics doesn't make sense in such scenarios.

So using Dynamic Sampling sounds like a reasonable advice and it probably is in many such cases.

Move the EM12c repository database

I have made a little mistake creating a RAC database for the OEM 12c repository-I now need a little more lightweight solution, especially since I’m going to do some fancy failover testing with this cluster soon! An 11.2.0.3 single instance database without ASM, that’s what I’ll have!

Now how to move the repository database? I have to admit I haven’t done this before, so the plan I came up with is:

  1. Shut down the OMS
  2. Create a backup of the database
  3. Transfer the backup to the destination host
  4. Restore database
  5. Update OEM configuration
  6. Start OMS

Sounds simple enough, and it actually was! To add a little fun to it I decided to the use a NFS volume to backup to. My new database host is called oem12db, and it’s running Oracle 11.2.0.3 64bit on Oracle Linux 6.1 with UEK. I created the NFS export using the following entry in /etc/exports:

Real Steel…

If you remove the humans from Real Steel, you pretty much have Rocky.

As far as the humans are concerned, Hugh Jackman is ok. The kid who plays his son is a little annoying, but to be fair, so are most of the kids in films. There are quite a few cheesy moments, but they are spread out so they aren’t like fingernails down a chalkboard.

I think the biggest problem with the film is the robots have no personalities. It’s just a giant and very expensive version of Rock’em Sock’em Robots. It’s hard to engage with a chunk of metal when it has no outward signs of personality. They are nothing like Transformers, which are totally real. :)

Having said that, its an OK bit of mindless fun. I tried to listen to other people talking on the way out to gauge the general reaction. It seemed to vary from “Awesome!” to “What a complete pile of xxxx!”. I guess I stand somewhere in the middle.

Cheers

Tim…




OOW2011 A.P. (After Presentation)

Wednesday