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Lessons of the trade : Troubleshooting database perfromance

If you have ever worked in an IT shop, you will know that the one thing you cannot escape from is issues related to Database performance. Now, I am no DBA in any way or fashion, but thought I should record some of the common issues and ways they have been overcome in my career so far. More for self records than trying to teach someone :).

  • Network Related
    • Check if the NIC (network interface) on the DB server has any speed mis match with the network device (most probably a switch) that it is connected to.
    • Check the latency between the application and the DB (pertains to applications connecting to DB over WAN links)
  • System Related
    • Check if a rouge process is using all the system resources.
    • Check if the disk sub system is performing optimally
      • Recommend using RAID 10 for transactional systems.
      • Don’t forget to check those batteries on the RAID controllers 🙂
    • Check if the DB is just running out of gas.
      • Long term capacity trending records come in handy here.
  • Database Related
    • Views are evil.. if created the wrong way. Esp, on data that is accessed frequently. Remember that you are now making two calls to the database. One to read the data, One to create the view.
    • Ensure your logs are not being writted ot (thx Ray for pointing out the typo) written to the same disk subsystem as your data files.
    • Indexes are good.. But only to an extent. If the size of your indexes is twice the size of your data.. you have an issue.
    • Check for invalid objects. You will be surprised how many times, people overlook this.
    • Sometimes, it helps to flush the SGA (Oracle specific). Be aware that it will slow down the response time for a while (until the cache gets populated again).
    • Avoid excessive monitoring. Esp. with tools that query the system tables quite frequently. This has a negative impact on the database performance.

Did you run into any strange situations and figured out a solution? Please feel free to add your comments below…

March 11, 2009 by Databases Technology Uncategorized 4

Can you still write?

i.e. Can you still write with your hand? I ran across this article (http://news.bbc.co.uk/2/hi/uk_news/magazine/7907888.stm) on the BBC, which predicts that we will have forgotten the art of handwriting in another 100 years or so. Imagine, a specialist having to decipher handwritten notes, although I should confess that I think it takes a specialist to read my handwriting now :).

As with most people of my age, I actually went through a formal “handwriting” class. I remember, we used to have special assignments, where all you did was write 🙂 . I used to write a lot of handwritten letters during my childhood, but as I grew up and started to use computers, my need to hand write something became less and less. If I remember correctly, the last handwritten letter I wrote was ~6 years ago!! It is so easy to type up an e-mail and send it off, but writing a letter makes you think and reflect on what you are writing. I do miss it 🙂

Speaking of things that are going to be “things of past”, I also think that most of the regional languages in this world will fade away in another 200-300 years. Everyone will speak some form of English :)..

So when was the last time, you wrote something (meaningful) with a pen or pencil?

February 27, 2009 by Fun Rantings Uncategorized 0

New Toy : Kindle 2.0

I have been looking at getting an e-book reader for some time now (yes.. even though I don’t have time, I still like to think I can read 🙂 ).. My sister and brother in law surprised me by getting me the newly released Kindle 2.0 (Thx Guys!!).. I think I am one of the first few people to receive it!!. Here are some pictures of the unpacking and the device itself

The Kindle in it’s original packing.. Getting pretty close to being as cool as Apple packaging

The most amazing thing (for me).. the USB/Power Cable.. Look how small the power brick is!!

 

First Thoughts??

Since, I didn’t have a previous e-book or the Kindle 1.0, I don’t have anything to compare it to. I think the styling of the device is very sleek and sexy. I like the alumunium backend (Reminds you of the first gen iPhone). The interface is OK.. Was not very impressed with it. I love the fact that you can browse Wikipedia anytime/anywhere with the built-in wireless connection for free!!

My next task is to figure out a way to get some content onto this baby. There are several books in the public domain (like the ones on Gutenberg.org) that I would like to get onto the Kindle first. Once, I feel comfortable with the unit, I will try some e-books from the Kindle store.

February 25, 2009 by Technology Uncategorized 1

HOW TO : Simple perl script to replace lines in file

Nothing fancy.. but here is a simple perl script to open a file, search for specific content in the a line and replace it with some other content.

open (SOURCE, "< source.xml") or die "Could not open file source.xml: $!\n"; open (DESTINATION, ">modfile.xml")
or die "Could not open file modfile.xml: $!\n";

while (defined($line =)) {
if ($line =~ m/YYYYYYYY/i) {
$line = "XXXXXXXXXXXXXXXXXXX\n";
}
print DESTINATION "$line";
}

close (SOURCE);
close (DESTINATION);

You are opening a file named source.xml, reading every line and if there is some text that matches “YYYYYYYY”, you are replacing the whole line with “XXXXXXXXXXXXXXXXXXX”. I am sure there are more elegant ways to write this :).. but this will do the trick too..

February 19, 2009 by HOWTO Programming Technology Uncategorized 1

I am a Disco Dancer..

What am I listening to now a days on my runs? This classic from the 1982 movie “Disco Dancer“..

Love the bling bling shiny dress of Mithun and the side kick girls with their saxophones and shorts 🙂

Check out two crazy moves… One is at 4:35 and the other at 7:10

And yes.. I love Disco 🙂

February 6, 2009 by Fun Music Uncategorized 0

Never give up..

Ran across this story on the BBC (http://news.bbc.co.uk/2/hi/asia-pacific/7871989.stm) about a 68 year old women in South Korea, who has attempted to get a car driving learning permit for the last 3 years. She attempted the exam 771 times, but hasn’t been able to score the minimum required score. What did she say, after failing again? “I will continue trying!!”.

All of us run into difficult situations from time to time. It can be a simple thing as trying to give up on a favorite food to reduce weight or attempting to reach a certain position in your career. And many times than not, we just give up.

I printed this news story and posted it in my office to remind me every day.. “Never Give Up!!”

P.S : Yes.. I do get my news from the BBC 🙂

February 5, 2009 by Fun Rantings Uncategorized 3

RECIPE : Bokkala Pulusu

Recipe for Goat soup (AKA known as Bokkala Pulusu in Telugu). Credit goes to Banda and his mom. This dish is mainly prepared in the Telangana region of the state of Andhra Pradesh. It is a spicy soup made from Goat meat with bones. Hence the name Bokkala Pulusu. Bokkala means bones and Pulusu means soup in Telugu.

Ingredients :

  • Goat Meat (with bones)
  • Onions
  • Green Chilli
  • Cloves
  • Cinnamon
  • Cardamoms
  • Garam Masala
  • Oil
  • Turmeric
  • Salt
  • Chilli powder
  • Tamarind Paste

Preperation :

  • Cut the meat into medium chunks. Don’t skin the meat from the bones. Let the meat cling onto the bones.
  • Heat some oil in a skillet and gently roast the cloves, cinnamon and cardamoms after crushing them.
  • After a minute, add the sliced onions and half cut green chilli.
  • When the onions turn golden, add the meat and gently turn it around until it becomes light pink.
  • Sprinkle some turmeric and add salt, chilli powder (according to your taste).
  • Let the meat cook for another 3-4 minutes and add garam masala.
  • Add plenty of water (should be at least 2 inches about the level of the meat) and the tamarind paste.
  • Let the meat cook for at least 1 hour on medium flame.
  • Serve hot with white rice..

Visuals :

The meat..

 

Cinnamon, Cloves &  Cardamoms

Onions & Chilli

All mixed together..

Served with a bunch of other dishes 🙂

February 3, 2009 by Food Uncategorized 0